United States Corvallis Environmental Environmental Protection Research Laboratory Agency Corvallis, Oregon 97330 PRODUCTION IN COASTAL SALT MARSHES OF SOUTHERN CALIFORNIA H. Peter Eilers* Department of Geography California State University Fullerton, California 92634 ------- PRODUCTION IN COASTAL SALT MARSHES OF SOUTHERN CALIFORNIA H. Peter Eilers* Department of Geography California State University Fullerton, California 92634 ~Current address: U.S. Environmental Protection Agency '200 SW 35th Street Corvallis, Oregon 97330 ------- PRODUCTION IN COASTAL SALT MARSHES OF SOUTHERN CALIFORNIA by H. Peter £ilers Department of Geography California State University Fullerton, California 92634 Grant No. R805438-01-1 Project Officer Harold V. Kibby Environmental Research Laboratory U.S., Environmental Protection Agency Corvallis, Oregon 97330 ENVIRONMENTAL RESEARCH LABORATORY OFFICE OF RESEARCH AND DEVELOPMENT U.S ENVIRONMENTAL PROTECTION AGENCY CORVALLIS, OREGON 97330 ------- DISCLAIMER This report has been reviewed by the Corvallis Environmental Research Laboratory, U.S. Environmental Protection Agency, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the U.S. Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. ii ------- ABSTRACT Production ecology in southern California coastal salt marshes was investigated by harvesting macrophytes and monitoring environmental factors (substrate salinity, pH, nitrogen, redox, water content, temperature, and tide level) at four locations—Sweetwater River Estuary, Los Penasquitos Lagoon, Upper Newport Bay, and Bolsa Bay—over an annual cycle beginning fall 1977. Net aerial primary production estimates computed by summing production in individual species and adjusting for interval death and shedding and disappearance of dead material averaged 3196, 3787, 2150, and 2494 g m-2yr_1 for study sites, and were 1.3 to 1.7 times greater than estimates computed by the method of Smalley (1959). Instantaneous rates of dis- appearance for dead material based on litter bag sets ranged from 2.2 to 2.7 mg g-1 day-1 and were lowest at Los Penasquitos Lagoon. Production levels were highest on creek levees and transition to upland and lowest in back levee depressions, fore levee slopes, and pans—suggesting that habitat, especially drainage and salinity, exerts greater control over macrophyte production in the marsh than does tide level alone. High levels of production in Salicornia virqinica and Frankenia qrandiflora at Los Penasquitos Lagoon suggests that production in some plant species may be increased by reduced tidal contact. i i i ------- TABLE OF CONTENTS Abstract iii Figures viii Tables ....... x Acknowledgements xii INTRODUCTION 1 Purpose and Scope 1 Salt Marshes and Production 1 Salt Marshes of Southern California . 2 CONCLUSIONS 4 METHODS 5 Study Areas ...... 5 Sweetwater River Estuary . 5 Los Penasquitos Lagoon 7 Upper Newport Bay . . . 9 Bolsa Bay 9 Sampling Procedures—Vegetation . . 12 Transect location and sample macroplots . . 12 Vegetation sampling and treatment of samples 13 Disappearance of dead material 14 Calculation of above-ground net primary production ...... 14 Sampling Procedures--Substrate 15 Salinity ..... 15 Reaction, redox, ammonia 15 Water content 15 Temperature 16 Elevation . . . . . 16 Tidal Inundation 16 Habitat Types 16 Data Analysis 17 v ------- RESULTS .. . 18 Vegetation . .. 18 Plant species . . 18 Biomass 18 Disappearance of dead material .; 20 Net Production of Stands . 20 Net Production of Species ........ 24 Substrate 26 Salinity 26 Reaction .......... 26 Ammonia 29 Redox 29 Water content 29 Temperature 33 Elevation 33 Habi tat Type 33 Fore: Levee Slope ..... . 36 Levee Crest . 36 Back Levee Slope ............ .... 36 Back Levee Depression 36 Slope Below Upland . . . 39 Upland Transition 39 Pan . . ; 39 Net Production and Environment . 39 Stand net producti on and el evati on 39 Species net production, elevation and plant communities .... 39 Stand net production and habitat type 42 Species net production and habitat type . 44 Explanatory models: net production and environment 44 DISCUSSION ........ 50 Disappearance of Dead Material 50 Net Production . 50 Role of tidal fluctuation 50 Elevation versus habitat . . . 52 Comparision with other salt marshes and latitudinal trends . . 53 The Spartina Question 55 Effects of Long Term Removal of Tidal Access--Bolsa Bay ...... 56 vi ------- LITERATURE CITED 58 APPENDICES 64 A. Macroplot, living and dead standing crop biomass 64 8. Net production for plant species by macroplot ......... 67 C. Substrate measurements ........ . 70 1. Salinity of substrate at 0 to 5 cm 2. Salinity of substrate at 45 to 50 cm 3. Salinity of substrate free-water 4. Reaction (pH) of substrate free-water 5. Ammonia in substrate free-water 6. Redox potential of substrate free-water 7. Water content of substrate at 0 to 5 cm 8. Water content of substrate at 45-50 cm 9. Temperature of substrate at 0 to 5 cm 10. Temperature of substrate at 45 to 50 cm D. Macroplot elevation and habitat type ..... 88 vi i ------- FIGURES Figure Page 1. Southern California salt marshes. Asterisk denotes seasonally closed ocean inlet. North is toward top of the figure 3 2. Sweetwater River Estuary. Square pattern denotes salt marsh; dashed lines represent diked and degraded marsh. Paradise marsh at left drains to Sweetwater marsh through a recently excavated channel. E Street-Vener pond marsh is at right center, G Street marsh at right. Arrows from top show position of transects B, A, and C 6 3. Los Penasquitos Lagoon. Square pattern denotes general extent of salt marsh. Marsh above and to the right of Atecheson, Topeka and Santa Fe tracks is partially degraded with low vegetation density and contains some brackish marsh. Arrows clockwise from top show position of transects D, C, B, and A. . . . 8 4. Upper Newport Bay. Square pattern represents salt marsh, and arrows from left show- location of transects B and A on Shell- maker Island, and C on Middle Island. PCH is Pacific Coast Highway. Incised area above "Upper" is housing development on former marsh investigated by Stevenson (1954) 10 5. Bolsa- Bay. North-south dike separates Inner from Outer Bolsa. Dashed lines denote degraded salt marsh contained largely within land owned by Signal Oil Company. Square pattern is salt marsh within Bolsa Chica Ecological Reserve. PCH is Pacific Coast Highway 11 6. Living and dead standing crop biomass means ± S.E. (g nr2) through the sample period for study areas. Solid line denotes living biomass, dashed line is dead biomass 21 7. Mean interstitial salinity (ppt) of substrate at 0-5 cm depth (solid, line) and 45-50 cm (dashed line) ± S.E. for study areas through the sample period 27 8. Mean pH of substrate soil free-water ± S.E. for study areas through the sample period 28 9. Mean ammonia (10-SM) of substrate free-water ± S.E. for study areas through the sample period 30 viii ------- 10. Mean redox potential (Eh-mV) of substrate free-water ± S.E. for study areas through the-sample period . 31 11. Mean water content (%-<- of moist weight) of substrate at 0-5 cm (solid: line) and 45-50 cm (dashed line) ± S.E. for study areas through the sample period 32 12. Mean temperature (°C) of substrate at 0-5 cm (solid line) and 45-50 cm (dashed Tine) ± S.E. for study areas through the sample period- 34 13. Vertical range of salt marsh in four southern California locations. SRE is Sweetwater River Estuary, L£L is Los Penasquitos Lagoon, UNB is Upper Newport Bay, BB is Inner Solsa Bay, BB is Outer Bosla Bay. Elevation in meters referenced to local mean higher water 35 14. Location of habitat types along a hypothetical marsh profile. Habitats- from left are Fore Levee Slope, Levee Crest, Back Levee Slope, Back Levee Depression, Slope Below Upland, Upland Transition, and Pan . 37 15. Macroplot net production and elevation. Production is SSTC in g m-^yr-1; elevation (m) referenced to local mean high water. ... 40 16. Elevational range of plant species in macroplot samples. Peak corresponds to elevation of maximum^ production. Elevation (m) referenced to local mean high water 41 17. Mean net production (g. n^yr-1, SSTC) by habitat type 43 ix ------- TABLES Table Page 1. Transect length and number of sample macroplots 13 2. Harvest dates 1977-1978 .... 13 3. Species frequency in quadrant samples 19 4. Species diversity of macroplot samples 20 5. Disappearance rates for dead material computed from dry weight of litter bag contents. Litter bag sets placed as follows: SRE, 10/22/77, LPL, 10/28/77; UN8, 11/11/77; BB, 11/11/77 22 6. Annual net production estimates based on three methods of com- putationi ST is method of Smalley (1959); SST is sum of individual species production based on Smalley (1959); SSTC is SST corrected for disappearance of dead material 23 7. Ratios of production estimates derived by the Smalley method (ST) to the sum of individual species production (SST) and sum of individual species production corrected for interval decom- position (SSTC) 24 8. Summary of net production for plant species 25 9. Mean elevation, number of species, and substrate conditions for habitat types 38 10. Mean species net production for habitat types .. 45 11. Pearson correlation coefficients for net production with eleva- tion, number of species and substrate variables 46 12. Summary of stepwise multiple regression—net production with elevation; number of species.; root zone salinity, water content, and temperature; and soil free water ammonia, redox and pH. ...... 47 13. Summary of stepwise multiple regression—net production (SSTC) with elevation; root zone salinity and water content and soil ammonia redox and pH.- " 49 x ------- 14. Disappearance rate- of dead material in salt marshes along the Atlantic and. Gulf Coasts of North America compared to those in southern California (mg g-1day-1). The range of values contains, means, for plant species sampled. . . . 15. Net production for salt marshes along the Pacific Coast of North America (g m-2yr-1) xi ------- ACKNOWLEDGEMENTS I thank Kathleen Kunz, Michael Sweesy, and Inda Taylor for field and laboratory assistance; their persistence and dedication is appreciated. I also thank Jim Lamprecht for assistance in computer programming and stat- istical analysis; Christopher Lee for help with tide level recording; Preston Johns, Ron Hein, and Dan Frazer of the California Department of Fish and Game for facilitating the study of Upper Newport Bay and Bolsa Bay by providing aerial photographs and advice; and Russ Belmer and Russ Iketa of the Los Angeles District Corps of Engineers for aerial photographs, reports, and elevational data. Most of all, I am grateful to Harold Kibby and the Environ- mental Protection Agency for making this study possible—and to Kay, Brandt, and Anna Eilers for support, encouragement,, and time to complete the work. xi i ------- INTRODUCTION Purpose and Scope This study was designed to answer four questions about macrophyte production in coastal salt marshes of southern California: a) what levels of production are achieved by plant species and plant communities; b) to what extent does production vary within and between marshes especially those with and without regular tidal inundation; c) what physical factors control or best explain variations in production; and d) how does production in southern California salt marshes compare with that at other latitudes on the Pacific Coast and at similar latitudes on the Atlantic Coast? Salt Marshes and Production A growing, literature suggests that coastal salt marshes are among the most productive of natural systems (Teal 1962, Cooper 1974, Clark 1974, Chapman 1976, Turner 1976). Salt marshes occupy a fortunate position between the limits of tidal inundation. Essential nutrients entrained by terrestrial runoff are transported, along with nutrients from coastal waters to marsh soils by tidal flux (Steever et aL 1976). While primary production in the marsh is high, marked variations in yield occur. Explanations for intramarsh variations in production, and species distribution as well, have involved factors related to tides; such as, frequency and duration of tidal inudation (Mahall 1974, Eilers 1975, Mahal! and Park 1976c), tidal range (Steever et al. 1976), waterlogging (Brereton 1971), drainage density and proximity to creek channels (Smalley 1959, Eilers 1975), and soil salinity (Adams 1963, Good 1972, Mahall and Park 1976b). Several authors (Tyler 1967, Valiela and Teal 1974, Patrick and Delaune 1976) have demonstrated the importance of soil nitrogen (especially ammonia) to the level of production, and others (Adams 1963, Tyler 1971) have shown that species occurrence as well as yield may be related to the abundance of soil iron. Production by salt marsh autotrophs is onlypartially consumed by i_n situ herbivory (Smalley 1959, Teal 1962). Much of the remaining dead leaves andi stems of marsh macrophytes are acted upon by bacteria and. transported from the marsh by tides as energy and nutrient-rich organic detritus (Odum and de la Cruz 1967). This material becomes an important food source for estuarine consumers, expecially filter feeders, and thereby aids in the maintenance of the high level of secondary production characteristic of coastal ecosystems. Export of particulate detritus is greatest for intertidal elevations in the marsh and decreases with declining inundation frequency (de la Cruz 1973, Eilers 1975, Heinle and Flemer 1976). In situ decomposition in the high marsh is likely to be more complete due to the rarity of tidal inundation and, 1 ------- therefore, export materials from more elevated positions take the form of soluble organics and nutrient ions which are carried seaward by rainfall and extreme high tides. Knowledge of marsh production in North American and its influence on general coastal productivity rests almost totally on investigations conducted along the Atlantic and Gulf Coasts. While much of the value placed on Eastern marshes has been applied to those of the West Coast by such agencies as the California Coastal Zone Conservation Commission (CCZCC 1975) and the San Francisco Bay Conservation and Development Commission (SFBCDC 1969), the productivity of Pacific marshes, especially those along the California coast, has yet to be fully demonstrated. Turner (1976) compared production values for salt marshes along the- Atlantic Coast and found a marked increase in yield with decreasing latitude. If this trend is present on the Pacific Coast,, high yields, and perhaps high detrital export, may be expected to characterize southern California coastal marshes. Salt Marshes of Southern California Of the 229 km2 of coastal salt marsh in California, approximately 10 percent occurs in the southern coastal counties of Santa Barbara, Ventura, Los Angeles, and San Diego (Speth 1970). Marshes occur in bays and lagoons (Figure 1) and may generally be considered in two groups—those in continuous contact with the ocean and those with seasonal or occasional contact (Purer 1942, Macdonald 1977). The former are subjected to regular tidal inundation; the latter are closed off by down-coast movement of beach sand except during periods of abnormally high tide or high terrestrial runoff—both of which are most common in the winter. Diked marsh, formerly open to tidal inundation but now removed from tidal influence., comprises a third group. Southern California coastal marshes have been recognized as important nesting and feeding areas for migratory birds (Frey et, al. 1970, U.S. Depart- ment on Interior 1972, Speth et aL 1976), and it lT likely that energy export, expecially from open marshes/ is important to coastal .fisheries resources. However, most southern California marshes are threatened by urban development. Indeed, many marshes have been reduced in area or completely destroyed by encroaching urbanism. For example, Los Angeles County once contained 2720 ha of salt marsh located mostly at Ballona Creek. At present, only 32 ha of degraded marsh remain at Ballona Creek as a result of marina construction and creek channelization (Darby 1964, Speth 1970). Mission Bay in San Diego County has suffered a similar loss of marsh; 8.4 ha remain of the nearly 960 ha once found there. 2 ------- PT. CONCEPTION SANTA BAR8ARA .Goleta Slough Carpenterla Marsh Ventura River* LOS ANGELES Mugu Lagoon Malibu Lagoon* Ballona Creek Anaheim Bay Solsa Bay Upper Newport Bay'"' San Mateo Creek* PACIFIC OCEAN Santa Margarita Riv.*—\ San Luis Rey River* —) 8uena Vista Lagoon*' Aqua Hedionda Lagoon- 8atiquitos Lagoon* San Oieguito Lagoon- Los Penasquitos Lag.- Mission 8ay' OCEANS IOE SAN 01 EGO San D iego. Bay ' Tiajuana River — MEXICO Figure 1. Southern California salt marshes. Asterisk denotes seasonally closed ocean inlet. North is toward top of the figure. 3 ------- CONCLUSIONS The following conclusions may be drawn from this investigation. 1. Estimates of net aerial primary production computed as the sum of individual species production with accounting for interval death and shedding and disappearance of dead material are higher than those computed by the traditional approach of Smalley (1959), are better suited to polyspecific stands than those of Smalley (1959) and Wiegert and Evans (1964), and are felt to be close to true net aerial primary production after herbivory. 2. Macrophyte production varies within and between southern California salt marshes. 3. Macrophyte production, especially in Salicornia virginica and Frankenia grandiflora, may be increased by reduced tidal contact. 4. Habitat, especially drainage and salinity, exerts greater control over macrophyte production in the marsh than does tide level alone. 5. Production estimates from this study, together with those of Eilers (1979), support an increase in salt marsh production with-decreasing latitude. 6. Production levels in southern California salt marshes are equal to or greater than those of salt marshes at the same latitude on the Atlantic Coast. 7. Future investigations of salt marsh production should be coordinated by a similar method to facilitate comparison of results and recognition of trends. 4 ------- METHODS Study Areas Four study areas were, selected to represent the variety and latitudinal extent of coastal salt marshes in southern California. Sweetwater River Estuary (SRE) The Sweetwater River drains 570 km2 of the Peninsular Range of San Diego County. From its. headwater area near Stonewall Peak (el. 1747 m) the river flows westward through Loveland and Sweetwater Reservoirs to the eastern edge of San Diego Bay, 10 km north of the Mexican border, between the cities of Chula Vista and National City. Salt marsh occupies estuarine deltaic deposits at the mouth of the river (Figure 2), and is floristically diverse with a predominance of mixed stands but Spartina foliosa occurs in pure stands along the Sweetwater River channel and locally Frankenia grandiflora, Batis martima and Salicornia virginica form monospecific, stands. The present marsh is much reduced from its former extent. Prior to the initiation of dredge spoil deposition on the marsh (the D Street fill) in 1947, 232 ha of salt and brackish marsh were present. By 1977, total marshland had declined to 83 ha and fragmented.into three units: Sweetwater marsh (42 ha), Paradise marsh (23 ha), and E Street-Vener Pond marsh (18 ha). The Paradise marsh, in addition to being partially filled, has been degraded by off-road vehicle use; diking has reduced tidal access in the E Street-Vener Pond marsh. Even though the dredge deposits exacted heavy toll on viable marsh and forced realignment of the main channel of the Sweetwater River, the surviving Sweetwater marsh is otherwise intact. Mudie (1970a) considered it to be the highest quality marsh area remaining within San Diego Bay. For this reason, and because of its estuarine setting with perennial tidal contact, the Sweetwater marsh was selected as a primary study site. Previous work concerning the Sweetwater marsh is limited primarily to several ecological inventories compiled by or for government agencies (Earth Sciences Associates 1971, Mudie 1970a, Mudie 1970b, Ford et aL 1971, San Diego Unified Port District 1972, Browning and Speth 1973) and to the assess- ment of environmental impact by proposed flood control of the Sweetwater River (U.S. Army Corps of Engineers 1976). In a classic study of San Diego County marshes, Purer (1942) referred briefly to floristic composition at Sweetwater and' included this marsh in a group with marsh at the south end of the Bay and at the mouth of Otay River for the presentation of monthly soil and water 5 ------- NATIONAL CITY CHULA VISTA SOME RR INTERSTATE 5 AT&SF RR STREET FILL lkm SAN DIEGO BAY Fig. 2. Sweetwater River Estuary. Square pattern denotes salt marsh; dashed lines represent diked and degraded marsh. Paradise marsh at left drains, to Sweetwater marsh through a recently excavated channel. E Street-Vener pond marsh is at right center, G Street marsh at right. Arrows from top show position of transects B,, A, and C. ------- salinity measurements. However, Purer (1942) does not specify the Sweetwater Marsh as her sampling site within the group. Ownership of the Sweetwater marsh is divided between the California Department of Transporation and Santa Fe Land Improvement Co. Vener Farms, Inc. cultivate tomatoes directly to the south. The D Street fill to the north is held by the San Diego Unified. Port. District. Los Penasquitos Lagoon (LPL) Located on the northern city limits of San Diego and 42 km north of Sweetwater, Los Penasquitos Lagoon is the seaward terminus of SoleildU diui Carmel Valleys (Figure 3). The lagoon name is after a creek in the upper drainage basin, although reference to the wetland as Torrey Pines Lagoon after its proximity to Torrey Pines State Reserve is also seen. The outstanding characteristics of Los- Penasquitos Lagoon are a depauperate flora and limited tidal access. Vigorous Salicornia virginica dominates the marsh in extensive pure stands. Frankenia- -gyandif^ora and Distich!is spicata occur locally. Even though the lagoon contains 156 ha of wetland (95- ha of salt marsh) and numerous well-defined tidal channels, some with depth to 9 m, sufficient tidal prism to maintain a perennial breech in the coastal strand is lacking. Only in the winter months when heavy-Wefter'STrecT runoff combines.with seasonal beach erosion does the tide penetrate the marsh. Summer runoff, when it occurs, may be simply impounded and gradually lost by seepage and7evaporation. Mudie et al. (1974) presented evidence of continuous ocean contact at least until 1888. A combination of railroad and highway construction after this date helped create present conditions by disruption of the drainage, system and constriction of the seaward channel. From 1965 to 1970 two sewage treatment facilities discharged secondary overflow into the lagoon. While this added flow helped to maintain more or less permanent ocean access during the period, nutrient enrichment led to the production of thick algae mats and high biological oxygen demand. With the loss, of this added, flow in 1970, and despite efforts to maintain ocean access (Inman and Nordstrom 1978), contact with the ocean continues to be seasonal. Los Penasquitos Lagoon was selected as a primary study site because, even with these human modifications, it remains the least altered of lagoons in southern California and is an excellent representative of a wetland with limited tidal control. Previous study of Los Penasquitos Lagoon includes detailed ecological descriptions (Bradshaw 1968, B.radshaw and Mudie 1972, Mudieet aH. 1974) and investigation of physical characteristics (Carpelan 1969). Purer (1942) included Los Penasquitos Lagoon (Soledad Station) among her 12 study sites. Zedler and Mauriello (1979) have made preliminary comparison of salt marsh production at Los Penasquitos Lagoon, Mission Bay and Tijuana River Estuary. 7 ------- TORREY PINES STATE RESERVE DEL MAR lkm PACIFIC OCEAN Fig. 3. Los Penasqultos Lagoon. Square pattern denotes general extent of salt marsh. Marsh above and to the right of Atcheson Topeka and Santa Fe tracks is partially degraded with low vegetation density and contains some brackish marsh. Arrows clockwise from top show position of transects D, C, B, and A. ------- Title to Los. Penasquitos Lagoon, including the salt marshes, is held by the State of California. Most of the marsh area is classified as a preserve and is under the jurisdiction of the State Department of Parks and Recreation. Upper Newport Bay (UNB) Newport Bay, 110 km north of Los Penasquitos Lagoon, is continuously open to the Pacific Ocean. Two strikingly different subdivisions separated by the Pacific Coast Highway (U.S. 101 Alt.) comprise the bay (Figure 4). Lower Newport Bay" is.a busy small craft harbor with high density urban development on the surrounding shore. Former salt marsh there has been^totally replaced by slips and "structures. Upper Newport Bay, by contrast, is 44-ttle developed, surroundedzby cliffs 10 to 30 m high (Newport Mesa), and, whi-le-some marsh has been converted to dwellings, about 58 ha still remains. The"fiarsh vegetation is floristica-lly diverse, but generally low in stature. Spartina foliosa is important along, creek and pure stands of monanthocloe 1ittoralis occur at highest levels. Upper Newport Bay is an important avian nesting and feeding area. Seventy species of birds are common to the bay and 89 others are occasional visitors (Frey et al. 1970). Although the Santa Ana River discharged into Lower Newport Bay for a t3me- around 1900, and may have occupied the upper bay in the geological past (Stevenson 1954), fresh water input to the upper bay is now from three low volume sources—San Diego Creek, Delhi Channel, and Big Canyon Creek. Aside from high nutrient loads, these sources transport great volumes of suspended sediment during the winter from the rapidly urbanizing watershed. High turbidity and rapid siltation of channels is of increasing concern (Stevenson 1978). Dredging of the main channel has been deemed necessary in the past and some spoils have been deposited on salt marsh (primarily near the distal end of Shellmaker Island). Upper Newport. Bay was selected as a primary study site to represent salt marsh in a bay setting with unrestricted tidal fluctuation. Its status as ecological reserve, latitudinal position, and presence of large areas of largely undisturbed salt marsh were also considerations. Studies of salt marsh plant ecology in Upper Newport Bay are limited to the work of Stevenson (1954), Stevenson and Emery (1958), and Vogl (1966). Descriptive treatment.of the upper bay in general is provided by Frey et al/ (1970) and Stevenson (1978). Bolsa Bay (BB) Bolsa Bay, 16 km north of Newport Bay and about 800 ha in area, occupies the seaward end of an alluvial-filied valley originally excavated at lower sea level in the Bolsa Chica-Huntington Mesa of western Orange County (Figure 5). Two subdivisions comprise the present bay. Outer Bolsa, directly to the west of the Bolsa Chica Mesa, is tidally controlled through a narrow channel 9 ------- NEWPORT BEACH BAY NEWPORT MESA (NEWPORT LOWER NEWPOR BAY JAMBOREE ROAD 1 km Fig. 4. Upper Newport Bay. Square pattern represents salt marsh, arid arrows from left show location of transects B and A on Shellmaker Island, and C on Middle Island. PCH is Pacific Coast Highway. Incised area above "Upper" is housing development on former marsh investigated by Stevenson (1954). ------- HUNTINGTON HARBOR D inner bolsa." pch PACIFIC OCEAN lkm Fig. 5. Bolsa Bay. North-south dike separates Inner from Outer Bolsa. Dashed lines denote degraded salt marsh contained largely within land owned tyy Signal Oil Company. Square pattern is salt marsh within Bolsa Chica Ecological Reserve. PCH is Pacific Coast Highway. ------- leading to adjacent Sunset Bay. A dike emplaced in 1899 by a private hunting club,, and containing, culverts with flap valves to prevent incursion of flood tides, extends from the southern edge of the mesa to the beach and separates •Outer from Inner Bolsa. Salt marsh in Inner Bolsa is Spartina foliosa grows with low vigor on creek margins and Frankenia grandiflora, Distich!is spicata, and Salicornia virginica occur with greater vigor at higher elevations. Oil Was discovered in Inner Bolsa. in 1926. Oil and gas exploitation began in 1943" after extensive diking and well pad construction. The State1 of California gained title to 140 ha of wetland (all of Outer Bolsa and part of the area outsvde the drilling area in Inner Bolsa) in 1973 and established the Bolsa Chica. Ecological Reserve under the jurisdiction of the Department of Fish and Game. After 1973 plans were made to return tidal fluctuation to State-held lands in Inner Bolsa (after dike construction around this port-ion of the reserve, limited tidal fluctuation was returned after nearly 89 years to Inner Bolsa in November 1978). Inner Bolsa was included as a primary study site for several reasons: Study of this.marsh before the return of the tides would provide some insight into, the ecological effects^ of long-term tidal removal, follow-up studies could be initiated to assess the impact of tidal restoration, and, most important, Inner Bolsa is representative of highly disturbed salt marshes in southern California (others are La Ballona Creek and Santa Ana River). Several authors, provided description of Bolsa Bay natural resources (Moffat and NichoT 1971, Speth et ah 1976, Henrickson 1976). Macdonald et al., (19710 assessed plant succesTfon since removal of tidal fluctuation. The most detailed treatment of the bay including, marsh ecology, however, is that completed by Dillingham Environmental Co. (1971) for Signal Properties, the major landowner. More recently, EDAW (1978) reviewed the work of Dillingham (1971) and considered various development alternatives. Sampling Procedures—Vegetation Transect location and sample macroplots With the aid of aerial photography, a system of transects was located in each study marsh. Each transect was so located as to include as much variety in vegetation pattern and habitat as possible. Semi-permanent wood stakes- were driven into the marsh at intervals along transects to ,serve as recovery points for sampling macroplots. Distance between macroplots was adjusted to maximize representation of pattern and habitat, and, in some cases, avoid creek channels. The position of the 11 transects containing 82 sample macroplots is shown in Figures 2 through 5. Transect length and number of macroplots along transects varied within and between study marshes (Table 1). 12 ------- Table 1. Transect Length and Number of Sample-Macroplots. No. of Marsh Marsh Transect Length (m) Macroplots Total SRE A 132 14 B 56 4 C 200 13 31 LPL A 116 8 B 13 3 C 123' 7 D. 60 3 21 UNB A 45. 6 B 70 7 C 266 12 35 BB A 30 5 5 Total 11 — -- 82 Vegetation sampling and treatment of samples Sample macrop lots were rectangular, 2.0 x 2.5 m, with the center of the short Teg adjacent to the wood stake and the long axis perpendicular to the right side of the transect (when looking seaward). Vegetation samples were taken at intervals of six to eight weeks for one year beginning October 1977 (Table 2). All above-ground, vascular plant material (living and dead) was harvested from within a 20 x 50 cm wire frame systematically located in the macroplot. Each sample was collected from a different position in the maicro- plot, and care was taken not to disturb future samples by progressively sampling deeper into the plot and by allowing a buffer of at least 50 cm between harvests. Table 2. Harvest Date 1977-1978 Session SRE LPL UNB BB 1 Oct. 14-22 Oct. 22-28 Oct. 29-Nov. 11 Nov. 11 2 Dec. 9-10 Dec. 16-17 Jan. 3-7 Jan. 7 3 Feb. 11 Feb. 17-18 Feb. 24-25 Feb. 25 4 Apri 1 14-15 Apri 1 21 April 21-22 Apri 1 28 5 June 7-8 June 12 June 14 June 15 6 July 17 July 18 July 19 July 19 7 Aug. 23 Aug. 23 Aug. 23 Aug. 23 13 ------- Plant material constituting each sample was placed in an opaque plastic bag, sealed with a short length of twisted wire, and refrigerated as soon as possible- to minimize fermentation (Milner and Hughes 1968). In the labora- tory, samples were sorted into green, attached dead, and dead of each species with a separate miscellaneous litter component of unsortable dead material. Each fraction was dried, in a gravity convection oven (Thelco model 17) at 85°C to constant weight and then weighed on a?balance sensitive to .01 g. Disappearance of dead material The rate at which dead material disappears from the marsh was estimated by using, a variation of the standard litter bag technique (Wiegert and Evans 1964). At the time of the first harvest, a number of macroplots in each study marsh wais selected to represent overall diversity of sites, and a mix of plant material approximating the species composition from each selected plot was divided into four plastic screen bags of 1 mm mesh. Litter bags were secured along the edges with staples and cloth tape after the contents of each had been weighed and an aluminum identification tag placed within. A sub-sample of plant material from each set was retained to establish proportionate dry weight at the initiation of the experiment. The bags, containing. 50 to 200 g of plant material and measuring 12 x 24 cm, were placed on bare soil in the respective macroplots and kept, in place by stout monofilament line fastened to pegs driven into the soil. At intervals of approximately three months, one bag from each original group of fbur was removed and its contents, freed from soil and new growth, dried to constant weight. If it appeared that inorganic accumulations were present (as was common for bags from macroplots near mudflats) the contents were combusted in a muffle furnace, and the ash-free dry weight was substituted for the-dry weight obtained above. Disappearance rate of dead material was calculated as r = [(dwt - dwt.) t dwt ] r (t.-t ) o i o i o where r = disappearance rate in g-g'day, dwt is dry weight at time zero, dwt. is dry weight at the end of the interval, ana (t.-tQ) is the interval in days. Calculation of above-ground net primary production Estimates of net aerial primary production (NAPP) were computed by three methods. Initially, the procedure of Smalley (1959) was followed whereby net production for intervals between harvests Was computed with reference to changes in live and dead biomass, then interval net production was summed over the annual cycle (ST). Because this application of the Smalley (1959) method does not account for variations in biomass of individual species which may be out of phase with total site biomass (Eilers 1975), a second estimate of annual production was computed (SST). In this case changes in individual species living and dead 14 ------- biomass were used with the Smalley (1959) approach to yield species annual production. Annual production for component species was then summed and adjusted for changes in miscellaneous litter (positive changes in miscel- laneous litter were added according to changes in total live biomass after Smalley 1959). The final approach (SSTC) to NAPP was a combination of the method of Smalley (1959) and Wiegert and Evans (1964). Here the summation of individual species net annual production (with accounting for miscellaneous litter) was computed as above (SST), then the average disappearance rate for the marsh in question was applied to interval changes in individual species and miscel- laneous dead biomass and appropriate losses added. Sampling Procedures—Substrate At the time of each vegetation sample harvest, a suite of substrate measurements was taken from each macroplot; Sali nfty Three aspects of substrate salinity were determined after a core sample 50. cm deep and 4 cm in diameter was extracted with a suction device. The upper and lower 5 cm sections were cut from the core, and sub-samples of each were individually wrapped in filter paper (Whatman No. 1), placed in a separate plastic syringe, and squeezed to force out drops of interstitial soil water for which salt content was determined with a Goldberg refractometer (Behrens 1965). As soil free-water percolated into the hole from which the core had been removed, samples were withdrawn by pipette and tested for salinity with the same instrument. Reaction, redox, ammonia Soil free-water, as obtained above, was further subdivided and subjected to three additional tests using a specific ion meter (Orion model 407a). Reaction (pH) was determined directly with a combination electrode. Oxidation-reduction potential (Redox) was measured directly with a combination platinum electrode and converted to Eh (Orion 1978). Analysis for NH3-N by an ammonia electrode followed the adjustment of sample pH to 11 by addition of sodium hydroxide (Banwart et al. 1972). Water content After sub-samples of the upper and lower 5 cm of the extracted soil core were taken for measurement of interstitial salinity, the remainder of. each was sealed in a plastic bag. In the laboratory, after initial weighing, samples were oven dried to constant weight, re-weighed, and percent water content (c) computed, as, c = [(w-d) -r w] • 100, where w is sample weight wet and d is sample weight dry. 15 ------- Temperature Substrate temperature was measured at 5 cm and 50 cm depths with a long-stem dial head thermometer (Reotemp) placed near harvested quadrats. Elevati on Elevation at each of 82 macroplots was determined with transit and stadia (Pugh 1975). At Sweetwater and Bolsa, levels were double run to nearby tidal bench marks (National City, R. 57 1926 and Los. Patos, 3; respectively). No tidal bench marks were found near Los Penasquitos, but numerous positions in the marsh had been surveyed: to National Geodetic Vertical Datum (NGVD) and monumented by the U.S. Army Corps of Engineers. Levels at Los Penasquitos were double run to several of these monuments and then converted to tide level by applying, a conversion factor midway between those published by the National Ocean Survey (NOS) for Scripps Institution, La Jolla, and Newport Bay Entrance (Corona Del Mar). Leveling at Newport was facilitated by recent work of the NOS for the Environmental Protection Agency (NOAA 1978). Here tide level monuments left by this survey served in the-double run procedure. Maximum acceptable closing error for all leveling was. set at 3 cm-. Tidal Inundation In-marsh tide level recordings were obtained for periods of six and four weeks at Sweetwater and Newport, respectively, with a recording gauge (Leupold Stevens Model 031). Inundation periods for increments of elevation were to be computed for the two marshes, but because the required simultaneous and long term recordings for nearby primary gauges could not be obtained from the NOS, this aspect of the study cannot be reported. Water levels at Los Penasquitos were recorded at each sampling period from a stake driven into the mud of a marsh creek, but continuous recordings there were not included in this study. After the return of tidal fluctuation to Inner Bolsa Bay in 1978, tide levels there were monitored with a staff gauge over one 48-hour period. Habitat Types In order to test the importance of location within marshes to NAPP, all macroplots were placed in one of seven topographically determined habitat types: 1) Fore Levee Slope, 2) Levee Crest, 3) Back Levee Slope, 4) Back Levee Depression, 5) Slope Below Upland,. 6) Upland Transition, and 7) Pan. 16 ------- Data Analysis Data analysis followed Snedecor and Cochran (1967). Descriptive stat- istics were produced for all vegetation and environmental data, analysis of variance provided a means to explore variation of NAPP within and between study areas, and relations between variables were investigated through cor- relation and-multiple regression analyses. 17 ------- RESULTS Vegetation Plant species Fifteen vastular plant species were recorded in sample quadrats (Table 3). Salicornia virginica was most frequent followed by Frankenia grandiflora and Batis maritima. Rare species included Cressa truxillensis found only at Los Penasquitos, and Lotus scoparius and Cordylanthus martimus found only at Newport. Species diversity (variety) was: greatest for Newport nearly as great for Sweetwater, but low for both Los Penasquitos and Bolsa. Monospecific stands comprised 28, percent of the macroplot samples (Table 4), and the mean number of species .for the 82 macroplots was 4.4. Biomass Macroplot living and dead standing crop biomass for harvest sessions is found in Appendix A. Macroplot LPL-15 recorded the living biomass high of 3915 g m-2 (session 1) but, while two macroplots located near creek channels (LPL-13, BB-5) showed no living material for two or more sessions, all others had living material all year. With the exception of UNB-17 and SRE-26, all macroplots contained dead biomass throughout the year. Maximum dead biomass for all sites was 4749 g m-? (SRE-8, session 6), and the annual mean for living and dead material over all macroplots was 751 and. 797 g m-2, respect- ively. Twenty-eight percent of the macroplots recorded a single living biomass peak, but most macroplots recorded two peaks (72%). Single peaks occurred most often in the summer, while dual peaks were most common winter-summer and summer-fall. No clear relationship between the number of different species, site elevation and the presence of single or dual peaks was detected, but the common occurrence of dual peaks suggested that the vegetation responds to summer warmth and fall, winter, and spring precipitation. For dead biomass in macroplots dual peaks were likewise most common (78% of macroplots) with winter-summer most frequent. Dual peaks in dead biomass tended to occur concomitant with dual peaks in live biomass. Mean living and dead biomass (Figure 6) reflected the persistence of dual peaks in dead biomass but tended to mask dual living biomass peaks. Mean living biomass minima occurred in March samples and greatest mean living biomass was found in June samples for all marshes with the exception of Los Penasquitos were the maximum was present in November 1977 (an August peak was 18 ------- Table 3. Species Frequency in Quadrat Samples. Marsh Total Species Batis maritima L. Cressa~truxi1lensis HBK. var. val1icola (Heller) Munz Cuscuta salinia Engelm. Djstichlis spicata (L.) Greene var. spicata Frankenia grandiflora Cham. & Schlect. Jaumea carnosa (Less.) Gray Limonium californicum (Boiss.) Heller Lotus scoparius (Nutt.) Ottley spp. scoparius Monanthocloe 1ittoralis Englem. Cordylanthus maritimus Nutt. Salicornia bigelovii Torr. Salicornia virginica L. Spartina folipsa Trin. Suaeda californica Wats. Triglochin maritimum L. • Number of Species Abbr. SRE(31)a LPL(21) UNB(25) BB(5) Freq(82) Bama 23 19 42 Crtr 1 1 Cusa 4 2 2 8 Oi sp 11 1 13 3 28 Frgr 21 6 13 2 42 Jaca 11 13 24 Lica 16 11 27 Lose 1 1 Moli 8 6 14 Orpu 1 1 Sabi 14 10 24 Savi 28 20 19 3 70 Spfo 9 16 3 28 Suca 16 4 20 Trma 17 13 30 12 5 14 4 15 ^ Total number of sample macroplots Nomenclature after Munz (1974) ------- Table 4. Species Diversity of Macroplot samples. No. of No. of %. No. of No. of % Species Macroplots Species Macroplots 1 23 28 6 6 1 2 10 12 7 11 14 3 4 5 8 5 6 4 6 7 9 6 7 5 7 9 10 3- 4 apparent in 1978). Relatively large standard errors for living and dead biomass means, especially for Los Penasquitos and Bolsa, emphasized the heterogeneity of vegetation along transects. Disappearance of dead material Dead plant material in most litter bag sets decomposed rapidly in the first interval after placement in the marsh, then the rate of disappearance declined (Table 5). This was expected because bags contained some recently living plant parts, and leaching of organic matter is most rapid in the first few days after death occurs (Odum et aL 1972). Site mean rates-ranged from .67 to 3.74 mg g-1 day-1; a single bag recovered from BB-4 after 106 days recorded the highest rate (9.43 mg g-1day-1), and the grand mean for LPL was well below that for the other study marshes. The lower rate at LPL was probably related to the woody Salicornia virginica placed in bags and dryness resulting from infrequent tidal submergence. Net Production of Stands NAPP varied with the method of computation (Tables 6 and 7). The Smalley (1959) method applied to changes in living and dead biomass without accounting for growth in individual species (ST) provided estimates that were an average of 1.44 times less than Smalley method applied to component species (SST) and 1.46 times less than SST corrected for decomposition of dead material between sample intervals (SSTC). Thus the Smalley method as orignally applied (Smalley 1959) appears to have severely underestimated NAPP, especially for multispecies stands, and much better estimates were provided for all stands when species growth patterns and litter decomposition were included. Yet, while SSTC was considered the best estimate of the three computed for each macroplot, values could be improved by accounting for losses to herbivory; Production estimates (SSTC) ranged from 164 g nHyr-1 at BB-5 to 6369 g m-2yr-i at LPL-9 with an overall mean for the four study marshes of 2986 g m-2yr-i. Los Penasquitos Lagoon was clearly the most productive marsh; Upper Newport Bay the least. Analysis of variance between marsh means showed that differences in production were significant (P<.001). 20 ------- B oO ¦w £ O 1800 - 1600 - 1400 - SRE 1200 - 1000 - 800 - 600 - T • i. | 0' 1 400 - 200 - 0 - 1800 £ 1600 1400 1200 1000 800 600 400 200 0 LPL A V i/'K —I [— N D 19 7 7 I H I 1— A M 1978 ~~r A 1800 - 1600 " 1400 - 1200 - 1000 - 800 600- 400- 200- 0- 1800-1 e 00 S o H S £ 1600- o 1400 1200- 1000- 800 600 400- 200- 0- UNB BB r 0 -1 r~ N D 1977 ~1 J ~r~ M ~T~- 1— A M 1978 i A Figure 6. Living and dead standing crop biomass means ± S.E. (g in-2) through the sample period for study areas. Solid line denotes living biomass, dashed line is dead biomass. ------- Table5. Disappearance Rates for Dead Material Computed from Dry Weight of Litter Bag contents. Litter Bag Sets Placed as Follows: SRE, 10/22/77; LPL,. 10/28/77; UNB, .11/11/77; BB, 11/11/77. Days in Rate Site x Days Marsh Marsh nig •g* day mq-g-dav Marsh Marsh SRE 1 113 3.45 UNB 1 106 306 .98 215 357 1.23 1.89 288 9 113 5.92 337 229 1.97 3 106 306 1.90 215 357 1.62 2.85 288 13 113 5.66 337 229 2.71 7 106 306: 2.25 2.5 357 2.10a 3.18 288 14 113 1.59 J 337 229 4.06 306 2.94* 357 2.27 2.27 15 113 .71 BB 2 106. 229 .26 145 357 1.04 .67 216 16 113 4.51 292 229 1.83 4 106 306 1.76 357 2.21 _ 2.57 Grand x 2.38 LPL 4 113 2.57 301 .36 351 .26 1.06 13 113 2.83 228 1.62 301 1.83 351 2.02 2.08 15 228 2.37 301 2.17 351 1.47 2.00 20 113 1. 50 228 3.08* 301 1.58 351 1.89 _ 2.18 Grand x 1.83 Rate Site x mg»g»day mg«g«day 2.26 1.40 1.15 1.07 6.42 3.07 2.67 2.79 4. 31 2.27! 2.26 2.14 Grand x .4_43 3.50 1.06 1.58 9.43 _ Grand x 1.47 3.74 2.75 2.65 2.64 9.43. 2.64 (9.43) * Computed from ash free dry weight Two values were used at BB. 22 ------- Table 6. Annual Net Production Estimates (g m-Syr-1) Based on Three Methods of Computation. ST is Method of Smalley (1959); SST is Sum of Individual Species Production based on Smalley (1959); SSTC is SST Corrected for Disappearance of Dead Material. Marsh ST SST SSTC Marsh ST SST SSTC SRE 1 3256 3284' 3576 LPL 6 4990 5438 5710 2 993 1703 1769 7 2131 2131 2289 3 3517 5708 5824 8 3006 4396 4616 4 2361 3163 3321 9 2784 5778 6369 5 1918 3019 3135 10 2909 2909 3056 6 2447 3554 3723 11 5073 5073 5303 7 3484 4100 4220 12 2390 4615 5416 8 3800 5459 5573 13 1464 1464 1767 9 2280 3133 3243 14 2531 2531 2690 10 1410 2143 2232 15 5649 5649 5848 11 1750 2857 3048 16 2896 2896 3224 12 1633 2346 2412 17 1737 1737 2047 13 1869 3692 3789 18 4968 4968 5219 14 1614 1614 1824 19 2563 4431 4737 15 620 620 665 20 2264 2264 2417 16 491 1414 1430 21 1501 1501 1582 17 3691 5184 5402 18 2457 2457 2659 X 3084 3539 3787 19 5734 5734 6231 S.D. 1259 1448 1528 20 1318 3100 3192 21 1047 3016 3096 22 1376 4674 4768 UNB 1 1356 1556 1708 23 1531 2643 2718 2 1265 1648 1790 24 1702 3264 3355 3 1609 2461 2574 25 2355 3388 3429 4 1287 2154 2234 26 885 1770 1782 5 1040 2057 2292 27 1364 2993 3102 6 1215 1215 1339 28 1848 2979 3208 7 1187 1572 1687 29 1284 1289 1318 8 2540 4007 4104 30 2121 2479 2532 9 918 1819 1849 31 1349 2469 2492 10 1646 2390 2552 11 1331 1931 1847 X 2049 2943 3196 12 1371 2142 2263 S.D. 1117 1203 1330 13 2389 2389 2621 14 1214 2607 2691 LPL 1 4777 4777 5011 16 780 1125 1161 2 1924 1924 2088 17 1005 1354 1380 3 3137 3137 3155 18 1322 2289 , 2331 4 2972 2972 3067 19 592 954 , 976 5 3113 3736 3922 20 1168 1224 1376 conti nued 23 ------- Table 6. (cont.) Marsh ST SST SSTC Marsh ST SST SSTC UNB 21 1133 2321 2414 BB 1 4282 4380 4638 2 Z 895 1380 1393 2 T152 2214" 2372" 23 2906 2906 3217 3 205S 3522 3622 24 3432 3933 4055 4 1158 1561 1676 25 1722 1722 1969 5 164 164 164 X 1469 2035 2150 X 1762 2368 2494 S.D. 673 770 795 S.D. 1559 1652 1731 ALL x 2120 2833 2986 S.D. 1220 1339 1408 Table 7. Ratios of Production Estimates Derived by the Smalley Method (ST) to Sum of Individual Species (SST) and Sum of Individual Species Corrected for interval Decomposition (SSTC). ST SST SSTC SRE T. 00 1.65 1.71 LPL 1.00 1.17 1.26 UNB 1.00 1.45 1.53 BB 1.00 1.49 1.35 ALL 1.00 1.44 1.46 Net Production of Species Species net production estimates based on the Smalley (1959) method corrected for interval decomposition (SSTC) are presented by macroplot in Appendix B and summarized by marsh in Table 8. It may be found that summing of component species production in macroplots yields a value less than total SSTC for the site as presented above. The reason for this discrepency is that harvested dead standing crop biomass often graded from parts recognizable as to species to amorphous duff with no recognizable species affinity. Accounting for this miscellaneous plant material, therefore, could not be included in species estimates (this material was included in macroplot estimates). Overall, the most productive plant species were Frankenia grandiflora, Salicornia virginica and Spartina foliosa. Qn an individual marsh basis, these species were most important at Sweetwater but at Newport Frankenia was conspicuously subdued, especially on transects A and B where it was all but replaced by Monanthocloe littoral is. Sparti na was not present at Los 24 ------- Table 8. Summary of Net Production for Plant Species (g m-2yr-x) Marsh Species X Min. Max. Freq. Marsh Species X Min. Max. Freq. SRE Bamaa 264 6 980 23 UNB Savi 634 10 3160 19 Cusa 72 2 238 4 Spfo 819 9 3217 16 (31 sites) Disp 240 4 1426 11 Suca 120 10 142 4 Frgr 880 4 6231 21 Trma 204 20 511 13 Juca 442 1 2395 11 Lica 200 1 862 16 BB Disp 901 74 1452 3 Mol i 232 43 562 8 Frgr 2318 72 4564 2 Sabi 231 1 713 14 (5 sites) Savi 1035 459 1525 3 Savi 1176 22 3732 28 Spfo 486 164 1032 3 Spfo 611 3 2659 9 Suca 161 1 882 16 Trma 159 7 792 17 LPL Crtr 127 2 All Bama 221 5 980 42 Cusa 1 1 MARSHES Coma 8 1 (21 sites) Oisp 1184 1 TOGETHER Crtr 127 2 Frgr 3274 1871 4864 6 Cusa 42 1 238 7 Savi 2789 1176 5848 20 (82 sites) Disp 362 4 1561 28 Frgr 1046 4 6231 42 Juca 338 1 2395 24 UNB Bama 168 5 620 19 Lica 203 1 862 27 Coma 8 10 Lose 5 1 Cusa 3 1 5 2 Moli 509 6 1351 14 (25) sites) Oisp 278 8 1561 13 Coma 8 1 Frgr 90 4 491 13 Sabi 173 1 713 24 Jaca 249 21 554 13 Savi 1483 10 5848 70 Lica 209 3 816 11 Spfo 716 3 3217 28 Lose 5 1 Suca 153 1 882 20 Mol i 877 6 1351 6 Trma 178 7 792 30 Sabi 93 1 466 10 a Species abbreviations from Table 3. ------- Penasquitoes. Distich!is spicata was more productive than Spartina at Bolsa. Indeed, Spartina at Bolsa appeared to partially die back in early 1978 with only poor aerial growth evident" the following summer, expecially at BB-5. Low production species—Cuscuta sal ina, Lotus scoparius, Cordylanthus maritimus— were of limited occurrence. Substrate Salinity Substrate interstitial salinity at the upper root zone (0 to 5 cm) and sub'-root zone depth (45 to 50 cm) by harvest session is found in Appendices C.l and C.2. Appendix C.3 contains salinity values for substrate free water. The peak, root zone1 salinity recorded was 125 ppt (LPL-17, session 2); the minimum root zone value was 5 ppt (UNB-7, session 2; UNB-7 and UNB-8, session 3). The sub-root zone salinity maximum1 of 105 ppt occurred at SRE-15 (session 7); the minimum of 3 ppt occurred at UNB-1 (session 3). Free-water salinity minimum and maximum were, respectively, 103 ppt (SRE-15, session 3) and 3 ppt (UNB-1, session 2 and; 3). In general, root zone, salinity for most macroplots was low in spring (sessions 3 and. 4) and high in summer (sessions 5, 6, 7). Sub-root zone salinity followed somewhat similar patterns, and free water salinity tended to be intermediate between root and sub-root zones. Comparison of mean harvest session salinities by depth and marsh (Figure 7) showed a summer peak for Sweetwater, Newport and Bolsa, a winter peak for Los Penasquitos. Comparison of salinities over the year in the root zone and sub-root zone revealed that winter precipitation reduced surface concentration and increased salinity at depth, while: summer drought tended toward greater concentration of salts at the surface. Los Penasquitos and, to a degree Bolsa, were somewhat out of phase with Sweetwater and Newport with higher surface salinities persisting through fall and winter and lower suface salinities in the summer. Perhaps the lack of tidal inundation during the summer at Los Penasquitos and Bolsa was responsible, but the reason for this is obscure. Annual mean salinities for the two depths were remarkably close, suggesting that overall variation for the substrate profile was slight. Overall "saltiness" as revealed by annual means was greatest at Sweetwater, least at Bolsa, and intermediate at Newport and. Los Penasquitos, although the former recorded greater mean surface salinity than the latter. Reacti on Substrate pH (Appendix C. 4) ranged from 5.2 (UNB-17, session 7) to 8.8 (UNB-1, session 2). Marsh harvest session means (Figure 8) for Sweetwater, and Newport peaked in the neutral range in the spring and revealed a shift to slightly acid conditions in the summer; means for Los Penasquitos peaked at slightly basic in the fall and reached a minimum of slightly acid in the early summer; means for Bolsa remained neutral to slightly basic throughout the year. 26 ------- Figure 7. Mean interstitial salinity (ppt) of substrate at 0-5 cm depth (solid line) and 45-50 cm (dashed line) ± S.E. for study areas through the sample period. ------- Ammonia Ammonia in substrate free-water varied greatly (Appendix C.5). The lowest value "of 1 x 10-5M occurred in. numerous macroplots in spring; the high value was 120 x TO-5 M (UNB-25, session 1). Occasionally an.insufficient quantity of soil free-water to test with the specific ion electrode was recovered, but it was felt that the data available did adequately represent trends in NH3. Mean NH3 values were generally highest in summer and lowest in spring (Figure 9). Sweetwater and Newport showed an increase in soil ammonia from spring to early summer, then a decrease in middle and late summer fol- lowed by a second increase in fall. Ammonia at Bolsa did not follow this dual maxima pattern, and the lack of data; for session 1 at Los Penasquitos leaves a question of where this marsh fits. With reference to annual means, Bolsa was clearly the best supplied with NH3, followed by Newport. Redox Redox potential (Eh) of substrate free-water (Appendix C.6) was lowest at BB-4 (-126 mV^, session 3) and highest at UNB-12 (542 mV, session 2). Low (<200 mV) and- negative potentials were most persistent at Bolsa;. Sweetwater displayed most consistantly high potentials. Gaps in the redox record (e.g., LPL, session 1; SRE, Session 2) were caused by a malfunction of the platinum electrode and, after the defective electrode was replaced, by insufficient sail free water to obtain a measurement. Even thougfr-data-for-aW-HnaeropTotj over all sessions was lacking, mean redox values (Figure 10) did reveal that low potentials, and hence prolonged anaerobic conditions—values <200 mV suggest the presence of reduced iron and manganese (Hesse 1972, Stolzy and Fluhler 1978)—were characteristic only of Bolsa and that the other study marsh substrates were- predominately aerobic. This was not surprising, through, because only at Bolsa were sample sites waterlogged at each visit, and only there was H2S frequently sensible. Water content Appendices C.7 and C.8 present root zone and sub-root zone percent water content of substrate samples. Minimum and maximum for each depth were 0 (UNB-7, session 5) and 89 (BB-3, session 3; BB-5, session 4), and 16 (LPL-8, session 1) and 70 (UNB-5, session 4), respectively. Means for harvest sessions (Figure 11) revealed that root zone water content was very frequently above water content at depth. This is explained by the nearly universal nature of substrate profiles—superficial fine-grained silts and clays, often with high organic content, over sand and silty sand with low organic content. Thus, even when both depths were saturated, the root zone carried the greater water proportion. A curious variation on this theme was discovered on transects UNB-A and UNB-B. Here the upper ends of both transects extended onto old dredge spoil deposits of high sand and shell content. Because spoil overlayed the old marsh surface, water content was often greater in deeper samples. However, lower extensions of both transects support the more common pattern. 28 ------- *UNB OBB i 1 1 1 1 1 1 1 1 1 1 1 OND JF HAM J J A S 1977 1978 Figure 8. Mean pH of substrate soil free-water ± S.E. for study areas through the sample period. ------- ^0 n 30 - X. in z. o o cn 20 - 10 0 J * UNB O BB * SRE $ LPL i 1 1 1 1 ——i 1— 1 r ONDJFMAMJ 1977 1978 ~i A Figure 9. Mean ammonia (10-^m) of substrate free-water ± S.E. for study, (areas through the sample period. ------- > e x w < O ro- 0 O 1 o O c- ^ ; - O 0- 3 ^ c CO £ ¦*0 OJ u o c 5 in 3 3 m > ^ 3J 1 Mj o 3 X o a S3 o Si S-^a X (D STS tr ^3 500 -i 400- 300- £ 200 H z w H O (X, 100- -100 J * SRE <* LPL #UNB OBB -T- r N D 1977 T" F ~T" M —r A 0 r~ M 1978 1 1 r J J A Figure 10. (lean redox potential (Eh-mV) of substrate free-water ± S.E. for study areas through the sample period. ------- SRE LPL % 5 1 I ~l 1- O N D 1977 ~r F M ~I r~ A M 1978 ~r J ~T~ A S 80 70 60 50 40 30 20 10 0 2 l- w T. 80 o in 70 60 50 AO 30 20 10 0 UNB BB i O T . • 1 i- £--- —s-' ~i r~ N D 1977 r~ F P M ~r A ~r *1 1978 ~~r J "T" A Figure 11. Mean water content (% of moist weight) of substrate at 0-5 cm (solid line) and 45-50 cm (dashed line) ± S.E. for study areas through the sample period. ------- Seasonal fluctuations in substrate- water content, while not of great magnitude, were nevertheless apparent. Most macroplots and, indeed, most marsh harvest session means, showed minimums. in the root zone during the summer and maximums between October and April. Subr-root zone water percentages foljowed the general pattern of root zone water content, but were less, seasonally variable. Annual water content means suggested that Bolsa was wettest at the surface and driest below, and that Los Penasquitos was driest overall. Soil dryness at Los Penasquitos was revealed by surface cracks and, on many occasions, tremendous pressures were required to force the coring device-into the soil substrate. Temperature Substrate temperature' varied with time of year and depth (Appendices C.9 and C.10). The highest temperature recorded for the root zone was 27.8°C (UNB-7, session 7), for the sub-root zone 23.3°C (SRE-15, session 5). Mini- mums were 8.3°C (LPL-18, session 3) and 11.7°C (several macroplots at LPL, session 3) for root zone and sub-root zone, respectively. In general, the substrate was warmer in the summer than it was in the winter. Root zone temperatures exhibited a greater annual range than those"atr sub-root levels and, in most macroplots, annual means for the root zone were higher by about 1°C. However, with reference to harvest session means (Figure 12), it was clear that an annual pattern of temperature contrasts between the two levels was present. In December and January temperature increased with depth; little change of temperature with depth was present February to April, although the root zone tended to be somewhat cooler in the early part of this period then somewhat warmer than the sub-root zone in the latter part; June to July temp- eratures in the root zone were higher than those below; by October a shift to cooler root zone temperatures then those below was apparent. Certainly variations in solar radiation through the year exert control on substrate temperatures, but temperature is also likely to be influenced by soil mositure from precipitation and tidal inundation and by foliar density of marsh plants. Elevation Sample macroplot elevations referenced to mean high water (MHW) ranged from -1.12 to 1.17 m (Appendix D). Most macroplots were located above MHW but,, conspicuously, all macroplots at Bolsa were below this tide level (Figure 13). Because macroplots were positioned to represent the variety of vegetation patterns in study marshes, macroplot elevations provided a good approximation of the vertical range of salt marsh. Habitat Type Each macroplot was assigned to one of seven habitat types during the final field session (Appendix 0). This classification represented a priori judgement and was not based on later knowledge of site_producti.on and analysis 33 ------- 1978 Figure 12. Mean temperature (°C) of substrate at 0-5 cm (solid line) at 45-50 cm (dashed line) ± S.E. for study areas through the sample period. ------- 1.5 -r 1.0 - 0.5 - o S MHW H -0.5 - UNB SRE LPL BBC BBa -1.0 - -1.5 -»¦ Figure 13. Vertical range of salt marsh in four southern California locations (m). SRE is Sweetwater River Estuary, LPL is Los Penasqu.itos Lagoon, UNB is Upper NewB.ort._BayBB. i_s Inner Bolsa Bay, BB is Outer Bolsa Bay. Elevation in meters referenced to local mean higher water. 35 ------- of seasonal trends in environmental variables. The distribution of habitat types along a hypothetical marsh profile is shown in Figure 14. Fore Levee Slope (FLS) Located adjacent to creeks and river channels and bounded on the upland side by a levee, the Fore Levee Slope habitat had the most intimate contact with tide waters and occurred at the lowest elevations (Table 9). Species diversity was low—usually only Spartina foliosa and, less "frequently, Salicornia virginica and Salicornia bigelovii were present. At marshes with and Without tidal fluctuation (Sweetwater and Newport versus Los Penasquitos and Bolsa), substrate salinity in this habitat fluctuated very little; most readings were near that of sea water. Redox potentials were generally low and, especially at Newport, often negative. The soil surface tended to heat rapidly by exposure to the sun at low tide. Levee Crest (LC) Levees along water courses were conspicuous in the field although they were often only 10 cm or less above adjacent marsh. This was often the site of vigorous growth in Salicornia virginica but, even at Los Penasquitos with its general low species diversity, multispecies stands were more common. Salinity extremes were greater here than in Fore Levee Slope, yet less extreme than other habitats. At Los Penasquitos mean salinity was lowest on levees. This habitat type was among the best drained; redox was high, soil water fow, and ammonia low. Back Levee Slope (BLS) On the opposite side of the levee from Fore Levee Slope, and at higher elevations, Back Levee Slope extended away from water courses. This habitat was fairly well drained, generally high in species diversity, and the most widespread habitat at Sweetwater and Los Penasquitos. At Sweetwater mean root zone salinity was highest in Back Levee Slope. * This habitat was universally low in ammonia. Back Levee Depression (BLD) Where water courses were well developed—Sweetwater, Los Penasquitos, Newport but not Bolsa—Back Levee Slope often ended in poorly drained shallow depression in which water remained on the surface for long periods after tidal inundation. Subsequent evaporation of impounded water in this habitat created high substrate salinity, especially at Los Penasquitos and Newport. Low redox values and high soil water content suggested persistent anaerobiosis. Ammonia levels were often high in this habitat, although not as high as those of Fore Levee Slope. 36 ------- SBU BLS BLO FLS r~ — ;—; DISTANCE Figure 14. Location of habitat types along a hypothetical marsh profile. Habitats from left are Fore Levee Slope, Levee Crest, Back Levee Slope, Back Levee Depression, Slope Below Upland, Upland Transition, and Pan. ------- Table 9. Mean Elevation, Number of Species, and Substrate Conditions for Habitat Types Annual Mean Elevation No. Salinity NH^ Redox Soi1 Sdi1 Marsh Habitat (m) Species (ppt) pH (10-s) (Eh) Water (%) Temp. (PC) n M mV FLS -.25 2.0 40 6.5 2.6 340 44 18 3 LC .31 5.8 48 6.5 1.5 417 46 17 6 BLS .28 7.6 58 6.3 1.0 405 48 17 8 BLD . 18 7.1 48 6.5 1.8 335 60 18 8 SBU .34 5.7 47 6.9 1.2 380 54 17 3 UT .48 2.0 44 7.0 1.7 384 39 17 2 P .52 1.0 90 6.9 .7 427 30 19 1 FLS .21 1.0 39 6.9 2.2 342 48 16 1 LC .28 1.2 33 6.5 2.5 324 53 15 5 BLS .21 1.2 39 6.8 2.1 333 48 15 9 BLO . 16 1.0 44 6.9 1.9 293 43 15 2 UT .49 2.3 39 6.5 2.5 366 34 16 4 FLS .30 2.9 35 6.6 12.6 190 65 17 7 LC .54 6.0 38 6.7 1.7 321 52 16 2 BLS .50 8.0 38 6.3 1.0 333 69 16 4 BLD .65 6.6 58 6. 1 3.5 300 71 17 7 SBU .77 9.0 39 7.2 1.0 344 23 16 3 UT 1.11 2.5 33 8.3 1.0 352 9 18 2 FLS -1.10 1.5 41 7.3 24.0 -3 78 17 2 SBU -.91 3.0 29 7.3 6.3 102 80 15 2 UT -.57 2.0 20 7.0 3.3 208 53 15 1 ------- Slope Below Upland (SBU) Below* the landward border, a sloping habitat—here labeled Slope Below Upland—often extended toward a water course or Back Levee Depression. Well drained and high in species diversity, this habitat type was generally low in ammonia and moderate in salt concentration. Upland Transition (UT) At the ecotone between marsh and upland, the most elevated habitat type- Upland Transition—was, identified. High redox potentials and Tow root zone water content denoted good drainage: Relatively low salinity and moderate- to low ammonia: were characteristic. Species, diversity at Los Penasquitos was highest in this habitat, but elsewhere the number of species was lower than might be expected. At Sweetwater and Bolsa, Frankenia grandiflora dominated this habitat; at Newport Monanthocloe 1ittorlis and an occasional upland plant species (e.g., Lotus scoparius) were important; at Los Pensquitos upland transition was taken by a combination of Frankenia grandi flora, Distichli:s spicata and Cressa truxillensis. Abnormally high pH in this habitat at Newport was most likely due to disintegration of shell in the substrate. Pan (P) Slight depressions at high marsh elevations collected water only from the highest tides. Through evaporation, expecially in the summer, salts were then concentrated and left at the surface. The Pan habitats were present in all four study marshes, but generally they contained little vascular plant life. At Sweetwater, however, a pan containing stunted growth of Salicornia v-irginica was sampled (SRE-15). Mean root zone salinity for this site was the highest recorded for all macroplots. Redox potential and root zone tempera- tures were high; ammonia and soil water were low. This habitat represents perhaps the most extreme marsh environment. Net Production and Environment Stand net production and elevation Strength of the relationship between macrpplot NAPP and elevation varied between study marshes (Figure 15). At Bolsa production increased dramatically with elevation (R = .85); relationships were positive but less dramatic at Los Penasquitos (R = .55) and Sweetwater (R = .43). No correlation between net production and elevation was detected at Upper Newport (R = -.08). Species net production, elevation and plant communities Plant species occupied marsh with certain elevational limits in study areas, and elevations of peak species production were generally unique (Figure 16). Moreover, vertical distribution of species and production peaks sug- 39 ------- 7000 6000 z 5000 o £ 4000 g 3000 £ 2000 1000 0 SRE / —i 1 1 1 1 -.2 0.0 .2 1 1 1 1 .4 .6 7000 6000 - 5000- z o H H 4000 - o n o o 3000 - at Ou H 2000 - w z 1000 - 0 - LPL ( 1 1 1 1 1 1——i 1 t- 1— 2 0 0 2 .4 .6 .8 ELEVATION (m) Figure 15. Macroplot net production and elevation, referenced to local mean high water. 7000 6000 - 5000 - 4000 - 3000 2000 - 1000- 0 UNB i r~ .2 —i 1 1 1 1 1 1 1 1 .4.6 .8 1.0 1.2 7000 t 6000- 5000- 4000" 3000- 2000" 1000- 0- BB i r -1.2 —i 1 1 1 1 t ' »~ •1.0 -.8 -.6 -.4 ELEVATION (ra) - . 2 Production is SSTC in g m-^r-1; elevation (m) ------- lose jk igure 16. Elevational range of plant speqjes in macroplot samples. Peak corresponds to elevation maximum production. Elevation (m) referenced to local mean high water. ------- gested several plant communities along, the elevation gradient in each marsh. At Sweetwater pure stands of Spartina foliosa extended to mudflat, but at elevations between -.1 and .1 m MHW, Spartina foliosa joined Salicornia virginica,. Salicornia bigelovii and Bat is mantima to form a multispecific commumty—Low Marsh. The High Marsh community at Sweetwater occurred between .1 and .5 m and was highly diverse; the Upland Transition community consisted of pure stands of Frankenia grandiflora above .5 m. Communities similar to those present at Sweetwater occurred at Newport but with some notable exceptions. Spartina foliosa dominated the entire Low Marsh and"; Frankenia grandi flora did not constitute the Upland Transition. Instead Monanthocloe 1ittoralis, Distichlis spicata and occasionally Limonium californicum occupied the highest levels. Only High Marsh and Upland Transition communities were discernible at Los Penasquitos. Salicornia virginica and Frankenia grandiflora dominated the former; the latter was dominated by Frankenia grandiflora, Distichlis spicata and Cressa. tfuxillensis. Low Marsh, High Marsh and Upland Transition were present at Bolsa. Pure stands of Spartina foliosa comprised Low Marsh; Salicornia virginica and Oistichlis spicata, with Some Sparti na foliosa and Frankenia grandiflora, inhabited High Marsh; Frankenia grandiflora and limited Distichlis spicata occurred in Upland Transition. Plant communities recognized in this study were essentially synonomous with the "low," "middle," and "high littoral" of other authors (Purer 1942, Vogl 1966). That peak production for each species usually occurred at an elevation unique to the species supported the principle of competitive exclusion (Gause 1934) that I observed in an investigation of species-elevation relationships in Oregon salt marshes (Eilers 1976). But it should be noted that in both investigations arrayment of plant species along an abstract elevation gradient suggested "abstract communities and, that in the field, the vegetation appeared more' as a complex mosaic. Stand net production and habitat type Variation in production between habitats was significant (pc.QOl). Clearly two habitat types, Levee Crest and Upland Transition accounted for the greatest macroplot production (Figure 17). This suggested that good drainage and associated aerobic soils., moderate salinities, and moderate to low soil ammonia provided conditions associated with optimal plant growth. In contrast, Fore Levee Slope and Back Levee Depression showed the lowest mean production (with the exception of Pan habitat) and thus anaerobic substrate, high root zone water content,, high soil salinity, and high ammonia were less supportive of high yield. Back Levee Slope and Slope Below Upland habitats recorded moderate yield which was perhaps a reflection of moderate environmental conditions comprising these types. Of the two, however, Slope Below Upland tended to be the more productive; the difference was likely attributable to slightly higher eleva- 42 ------- 5000 4000- 3000- 2000 1000- 0- 5000 4000- 3000- _T 2000- I ^ L000 I E 30 z o a O a: a. fr- bJ Z 0 ™ 5000 -j 4000 - 3000 - T 2000- ¦ O ' X 1000 - 0 - 5000 i 4000 - 3000- 2000- T 1000- f 0 1 0 - 1 BB FLS —r- LC BLS BLD HABITAT SBU UT Figure 17. Mean net production (g . nryr-1, SSTC) by habitat type (±S.E.). ------- tion in this habitat. Inhibitory effects of high salinity appeared to out- weigh benefits of high elevation and good soil aeration in the Pan habitat type. Species net production and habitat type Even though most plant species occurred in more than one habitat type, each displayed maximum production and therefore maximum affinity to a par- ticular type in each marsh (Table 10). Fore Levee Slope was favored by Spartina foljosa, and Salicornia bigelovii grew best in this habitat only at Sweetwater. Sal icornia virginTca achieved maximum production in Levee Crest where this habitat was available. Jaumea carnosa, Triglochin maritimum and Cuscuta salinia did best in Back Levee Slope and Back Levee Depression; Batis maritima produced at maximum in Back Levee Depression at Newport and Slope Below Upland at Sweetwater. Peak production of Limonium californicum and Suaeda californica occurred in Slope Below Upland. Habitat affinities of several species varied from one marsh to the next. Most curious in this regard was Frankenia grandiflora. Upland transition was its most productive habitat at Sweetwater and Bolsa; at Los Penasquitos, while more productive in Back Levee Slope, it produced high yield_s in Upland Transition. However, at Newport, its maximum growth (a low 134 g m-2yr-1) occurred in poorly drained Back Levee Depression habitat. Two explanations were possible. Competition with Monanthocloe littoral is may have excluded Frankenia grandiflora from Upland Transition at Newport, or perhaps, coarse grained substrate there favored Monanthocloe littoral is but did not retain enough moisture- for establishment of Frankenia grandiflora. At any rate,.the low production of Frankenia grandiflora at Newport merits further investiga- tion. Distich!is spicata" displayed the greatest variation in habitat affinity; it achieved maximum production in a different habitat in each study marsh. From the foregoing it was clear that, while for some species maximum production always occurred in the same habitat or closely related habitats (e.g., Sparti na foliosa, Jaumea carnosa), peak production for other species (e.g., Distich!is spicata) was prone to intermarsh variability. Explanatory models: net production and environment Pearson correlation coefficients which indicate the degree to which two variables covary were computed for NAPP (as SSTC) with macroplot elevation, number of species, and annual values (mean, minimum, maximum and range) for substrate variables (Table 11). On the strength of coefficients, eight independent variables were selected for stepwise multiple regression analysis as noted in the table. Table 12 resulted from the initial analysis. For Sweetwater, root zone temperature entered the regression equation on the first step with a significant R2 of .54. The addition of root zone water content, root zone salinity, elevation, and free water ammonia on successive steps created a regression model that explained 72 percent of the observed variation in._macr.op lot production. Subsequent steps did not add to the model. Salinity 44 ------- Table 10. Mean Species Net Production for Habitat Types (g m-Syr-1) SRE LPL UNB BB Habitat Species FLS LC BLS BLD SBU UT Bama 96 151 215 919 Cusa 2 238 74 28 Disp 238 443 78 Frgr 773 488 137 698 4838 Juca 104 465 981 Li ca 288 68 157 476 Moli 303 241 49 Sabi 458 182 330 3 Savi 1122 2196 1048 810 1020 131 Spfo 2034 3 166 175 Suca 149 83 97 363 Trma 43 166 178 197 Crtr 127 Disp 1184 Frgr 2574 3347 3459 Savi 1767 4006 2499 2636 1585 Bama 155 198 .81 509 45 Coma 8- Cusa 1 5 Disp 780 444 70 152 401 Frgr 27 14 134 101 Juca 284 96 392 184 88 Lica 3 67 57 522 357 Lose 5 Mol i 6 969 1175 Sabi 1 1 223 67 1 Savi 324 1980 175 764 357 Spfo 1661 50 52 194. Suca 16 155 Trma: 63 261 352 187 53 Disp 891 74 Frgr 72 4564 Savi 459 1323 Spfo 598 665 45 ------- Table11. Pearson Correlation Coefficients for NAPP with Elevation, Number of Species and Substrate Variables. Variables Selected for Regression Analysis are Indicated. Variable SRE LPL UNB BB AL-t Elevation a .43 .55 -.08 00 en .07 Number of Species a .13 .51 .02 .60 .09 Salinity x3''3 -.30 -.53 -.39 -.79 .27 min. -.17 -.24 -.32 -.76 -.19 max. -.27 -.19 -.18 -.41 .06 range -.20 -.15 -.02 .62 .13 pH xa .10 -.45 .07 -.70 -.06 min. .01 -.28 .02 -.79 -.08 max. .01 -.31 .24 -.37 -.04 range -.12 -. 07 .34 .09 .01 NHS- x -.10 -.38 -.03 -.57 -.26 min. .17 -. 32 -.19 .19 -.19 max. -.18 -.38 .09 -.86 -.25 range -.18 -.38 .09 -.86 -.25 Redox x .45 .05 .04 .70 .30 min.a .45 .32 .26 .74 .37 max. .23 -.03 .21 .37 .18 range -.27 -.38 -.16 -.86 .39 Soil Water x3'*3 -.19 -.14 -.19 1 cn -.32 min. -.29 -.12 -.25 -.48 -.38 max. -.03 -.20 -.17 -.51 -.19 range .38 .03 .34 .40 .31 Temperature xa'^ -.74 -.08 -.66 -.73 -.42 min. -.46 .31 .01 -.68 -.38 max. -.13 -.38 -.45 -.85 -.24 range .18 -.49 -.37 -.93 -.11 ^Selected as independent variables for regression analysis. Root zone 46 ------- Table 12. Summary of Stepwise Multiple Regression—NAPP with Elevation; Number of Species; Root Zone Salinity, Water Content, and Temp- erature; and Soil Free-Water Ammonia, Redox and pH. Step Variable Enteri ng. Multiple R R2 Simple R SRE 1. Temp .74 .54 -.74 2. Water .76 .58 -.19 3. Salt .79 .62 -.30 4. Elev .83 .68 .43 5. nh3 .85 .72 .17 6. Sped es .85 .72 .14 7. Redox .85 .72 .45 LPL 1. Salt .53 .28 -.53 2. Spp .73 .54 .51 3. Elev .78 .61 .55 4. Temp .79 .63 -.08 5. Water .79 .63 -.14 6. Redox .79 .63 .32 7. pH .79 .63 -.45 8. nh3 .79 .63 -.32 UNB 1. Temp .70 .49 -.70 2. Water .74 .54 -.23 3. Salt .75 .56 -.39 4. Species .77 .60 .00 5. Redox .78 .61 .26 6. nh3 .79 .62 -.20 7. pH .79 .63 .15 8. Elev .79 .63 -.01 BB 1. Elev .85 .73 .85 2. Species .99 .98 .60 3. Water .99 .99 -.53 entered the equation first for Los Penasquitos (R2 = .28) followed by species and elevation. The three variables together accounted for 61 percent of the variation in production; continuation of the stepwise process.added little. Temperature was again the first independent variable to enter for Newport (R2 = .49) and, on the next step, it was joined by root zone water content to explain 54 percent of NAPP variation. Addition of the remaining variables increased the explanation by small increments to 63 percent. Elevation and number of species provided a strong combined R2 of .99 for Bolsa, but soil water content was the only additional variable to enter and it added little. 47 ------- Analysis to this point suggested that high root zone temperature was an important constraint on NAPP in tidally controlled marshes. It might be expected that more frequent inundation at lower elevation moderates temp- eratures, yet the correlation between mean root zone temperature and elevation at .Sweetwater was strongly negative (R = -.67). At Newport, however, this correlation was moderately positive (R = .23) and supportive of a tide- temperature relationship. A check of mean temperatures recordied for Newport macroplots revealed that those contributing most to the-positive- correlation were located on old dredge spoil and thus this apparent positive relationship should be approached cautiously. Furthermore, the question of temperature modification by marsh plants needed to be considered. It was reasoned that high production should correlate well with low root zone temperature because of shading by high foliar density and, therefore, high production itself could be partially responsible for lower soil temperature. Inclusion of number of species was also questionied because, as a vegetation characteristic, its presence in the analysis would not help to explain variation in NAPP in terms of environmental factors. With these considerations in mind, temperature and number of species were excluded from the independent variables and regression models recomputed (Table 13). Redox, elevation, and root zone salinity combined in a new model for Sweetwater to explain 56 percent of NAPP variation; addition of NH3 and water content of the root zone increased the R2 to .66. The combination of salinity, elevation, NH3, salinity, and pH produced R2 = .56 at Los Penasquitos. Salinity and redox were most important (combined R2 = .26) at Newport, but the expansion of the regression equation to include elevation, soil water, and pH increased the R2 by .11. Elevation, soil water and soil salinity entered the equation for Bolsa (R2 = .99). Treatment of all marshes together produced a combined R2 for redox and salinity of .29, but further addition of variables did not improve the multiple R2. A combination of variables provided at least a partial explanation of NAPP variation in each study marsh, but variables related to soil aeration and waterlogging (redox, soil water content, and, in some ways, elevation) and soil salinity were consistently important constraints on production. The models suggested that high production was most likely to occur at well- drained, aerated, low-salinity locations (such as Levee Crest and Upland Transition habitats) and that low production could be expected in sites where water collects on the marsh and remains for long periods (Back Levee Depression and Fore Levee Slope habitats). Low production could also be expected where elevated soil salinity results from evaporation of surface water (Back Levee Depression at Los Penasquitos and Newport and Pan at Sweetwater). Production was apparently not limited by nitrogen (NH3) as suggested by Valiela and Teal (1974). Only in the regression model for Sweetwater did a positive relationship with ammonia occur. Strength of regression models varied between marshes, but the general levels of explanation for differences in macroplot production were high and significant (all < .14). A search for the source of unexplained variation in production (1 - R2) through computation and graphic presentation of residuals to each model produced no consistent patterns. Perhaps the inherent vari- ability of marsh vegetation and limitations imposed by sampling each time at a 48 ------- Table 13. Summary of Stepwise Multiple Regressiorr-NAPP with Elevation; Number of Species; Root Zone Salinity, Water Content, and Temp- erature; and Soil-Free Water Ammonia, Redox and pH. Step Variable Enteri ng Multiple R Multiple R2 SimpleR SRE 1. Redox .45 .21 .45 2. Elev .59 .36 .43 3. Salt .75 .56 -.30 4. nh3 .78 .62 .17 5. Water .81 .66 -.19 6. PH .81 .66 . 10 LPL 1. Salt .53 .28 -.53 2. Elev .69 .47 .55 3. nh3 .71 .50 -.31 4. Water .72 .52 .32 5. Redox .75 .56 .32 6. PH .75 .57 -.45 UNB 1. Salt .39 .15 -.39 2. Redox .51 .26 .26 3. Elev .53 .28 -.01 4. Water .56 .31 -.28 5. PH .61 .37 .14 BB 1. Elev .85 .73 .85 2. Water .93 .87 -.54 3. Salt .99 .99 -.79 All 1. Redox .37 .14 .37 2. Salt .54 .29 27 3. nh3 .54 .29 -.19 4. PH .54 .29 -.06 5. Water .55 .30 -.32 6. Elev .55 .30 .07 different position within macroplots were factors. Other variables not included in this investigation (such as soil texture, soil nutrients other than ammonia-N, water table depth, and animal trampling and herbivory) could have provided additional explanation. 49 ------- DISCUSSION Disappearance of Dead Material The rate at which dead material disappears from the marsh is closely related to several factors including temperature, precipitation, tides, and the organic nature of marsh plants (Kirby and Gosselink 1976). Rates could be expected to vary with seasons and with the mix in species composition as was observed in this study. Wiegert and Evans (1964) suggested two methods- litter bags and' paired plots—by which to estimate the disappearance of dead material and applied each in a study of old field vegetation in Michigan. Subsequently, several authors applied one or the other of these techniques to investigations of salt marshes along, the Atlantic and Gulf Coasts of North America, The range of their estimates,, those of Wiegert and Evans (1964), and estimates generated by this study are presented in Table 14. Disappearance rates for southern California marshes compare closely to those obtained by the litter bag technique elsewhere, but litter bag estimates are, in general, lower than values obtained by utilization of paired plots. Litter bags exclude larger detritivores and retard water movement that might otherwise remove dead material (Hopkinson et aK 1978). The paired plot technique is more sensitive to tidal deposition and removal of dead material and to consumer activity. Therefore, paired plots are likely to approximate decom- position under natural conditions better than the Titter bag methods. Thus, even though disappearance rates determined by the litter bag technique provide insight into the decomposition process and allow adjustments to dead biomass for computation of NAPP, resultant production is probably somewhat under- estimated by this method. Net Production Role of tidal fluctuation The importance of tidal action to nutrient cycling and production in salt marshes is well recognized (Odum 1961, Teal 1962, Steever et ah 1976) and most, if not all, previous investigations have been confined to salt marshes with unrestricted tidal access. The inclusion of Los Penasquitos and Bolsa in this study allows comparison of production with and without regular tidal control. It appears that in southern California, salt marsh macrophyte pro- duction may be helped by restricted tidal contact. Mean production at Los Penasquitos was 1.3 to 1.6 times greater than that at Sweetwater and 1.9 to 2.2 tiroes greater than Newport (based on ST and SSTC values). Waterlogging reduced production at Bolsa and the anomalously low. level of the marsh there prevents direct comparison with Los Penasquitos or other sites, but it may be noted that production of macroplot BB-1:was above that of all Newport sites 50 ------- Table 14. Disappearance Rate of Dead Material in Michigan and Salt Marshes along the Atlantic and Gulf Coasts of North America Compared to Salt Marshes in Southern California (mg g-1day-1). The Range of Values Contain Means for Plant Species Sampled. Method Source Locale Litter Bags Pai red Plots Wiegert and Evans (1964) Michigan .3 - 4.6 1.3-13.6 Linthurst and Reimold (1978) Mai ne to Georgia .1 - 34.8 Odum and de la Cruz (196?) Georgia 1.2. - 3. la Kirby and Gosselink (1976) Louisiana 4.9 - 6.3a White et a1_. (1978) Louisiana CM CO i Hopkinson et ah (1978) Louisiana 4.0 - 18.9 This Study California .7 - 3.7 aSpartina alterniflora only. and above the mean for Los Penasquitos. Conditions in the lagoon are perhaps near ideal for growth of Salicornia virginica and Frankenia grandiflora; elsewhere both exhibit greatest vigor in well-drained levee and high marsh sites with infrequent inundation. Tidal access to Los Penasquitos is restricted to winter and spring months when the marsh is less photo- synthetically active. Lack of tidal fluctuation may further support high production in Salicornia virginica and Frankenia grandiflora by reduction of species diversity. Nearly all plants recorded in all sample macroplots occurred at Sweetwater and Newport, and polyspecific stands were very common in both. Monospecific stands characterized Los Penasquitos and Bolsa, and the total flora recorded from these sites was limited to five and four species, respectively. Furthermore, the mean disappearance rate of dead material at Los Penasquitos was 1.3 times Tower than that for Sweetwater and 1.5 times lower than that for Newport. This implies that nutrient cycling at Los Penasquitos is retarded in comparison to tidally controlled sites; but higher production, larger litter accumulation, and infrequent inundation at Los Penasquitos suggests that nutrients tend to remain on site and benefit marsh plants rather than estuarine organisms as is likely to be the case with regular tidal flushing. 51 ------- Elevation versus habitat In an earlier investigation of an Oregon coastal salt marsh (Eilers 1979), I observed an increase in macrophyte production with elevation, but production in certain sites such as creek levees ancLback.._lev.ee depressions did rrart conform to the general gradient pattern. Little reference to production ecology appears in the literature, but numerous authors who have studied Atlantic and Gulf Coast marshes report higher production of Spartina alterniflora on creek banks than in inland areas (for example, Smalley 1959, Kirby and Gosselink 1976). Brereton (1971) found that Salicornia grew with greatest vigor in aerated, soils; Puccinellia maritima performed best in water logged soils. This^ leads- to the question of the relative importance of elevation and habitat in terms of production levels. The current investiga- tion of southern California marshes sheds some light on this question. It. appears that the strength of the relationship between production and tide levels depends on the marsh under consideration. A very strong positive relationship occurred at Bolsa-, no relationship was detected at. Newport, and a moderately positive relationship was observed at Los Penasquitos and Newport. Winfield and Zedler (1976) found a parabolic relationship between net pro- duction and elevation classes in salt marshes of the Tijuana River Estuary (southern California) with-the dip at mid-elevations. Mahal 1 and Park (19.76a) recorded minimum production at the Spartina-Salicornia ecotone in San Francisco Bay. To. relate production to elevation alone may, therefore, produce conflicting results. As this investigation suggests, production in salt marsh vegetation is more tuned to a combination of environmental factors—soil water content, redox potential, salinity, inundation period, and. elevation—than to an abstract elevation gradient alone. Indeed, elevation controls inundation period, but microtopography and soil texture control drainage. The degree of drainage in turn influences soil aeration, salinity, redox potential, pH and nutrient levels. At any given elevation, several different habitats—each composing a different combination of environmental variables—may occur. Back levee depressions may be found at the same absolute elevation as levee segments, and intramarsh Pan may occur at the same elevation as Upland Transition. Furthermore, microtopography may be influenced by tide level to create- strongly contrasting habitats. Poorly drained areas at low elevation—Back Levee Depressions—are perpetually water- logged, but frequent tidal inundation prevents extreme salt concentrations. Infrequent tidal flooding of elevated depressions—Pan habitat—leads to very high salt concentrations in the soil root zone through prolonged evaporation, but soils are generally not waterlogged and redox potentials are high. It appears, then, that habitat exerts greater control over production of salt marsh vegetation than does elevation (and tidal inundation) alone. This suggests that if a strong relationship between production and elevation is observed, as at Bolsa, the various, habitats are not fully represented and/or the spatial arrangement of habitats supports the production-elevation relationship. Creek levees and Back Levee Depressions are hot present at Bolsa and, because soil salinity and waterlogging decrease sharply with increased elevation, the strong positive relationship is not surprising. The weak production-elievation relationship at Newport attests to the occurrence of contrasting habitats (and hence different levels of production) at similar elevations. 52 ------- Comparison with other salt marshes and latitudinal trends- Reported studies of production in salt marshes along the Pacific Coast of North America are scarce, and thus a comparative treatment is difficult. The task if further complicated by the lack, as Kirby and Gosselink (1976) found when they sought comparisons for their work in Louisiana, of uniformity in methodology among studies. Table 15 brings these reported studies together and comparisons, at least among estimates dierived by similar methods, are possible. Production in the four southern California marshes studied is from 1.5 to 2.8 times greater than that of Nehalem Bay. This is not unexpected because production in Oregon is confined to the warm months, and aerial portions die back to ground level each fall. That all four marsh estimates (SST) from1 this study are well above values computed for Tijuana River Estuary by Zedler and Maurillo (1979) is curious. Sweetwater is located closest to Tijuana; they are similar in species com- position and. setting (estuaries with some fresh water inflow), but production in monospecific stands of Spartina foliosa is 2.5 times greater at Sweetwater (2033 versus 832 g m-Syr-1). Steever et al. (1976) found that production of Spartina alterniflora in Connecticut marshes increases with tidal range. Sparti na foliosa is the ecological equivalent of Sparti na alterni flora in California marshes. Tide range (MLLW to MHHW) at Sweetwater is 1.8 m; tide range at Tijuana has not been published. However, the National Ocean Survey has operated a tide recording station on the municipal pier at Imperial Beach since 1971. The pier extends into the Pacific Ocean 2.5 km northwest of the entrance to Tijuana Estuary, and tide range there is 1.6 m—very close to that at Sweetwater. Warme (1971) reported poor establishment of Spartina foliosa at Mugu Lagoon where tidal range is reduced to .4 m by a sill of accumulated sand at the lagoon entrance. The disparity in production levels for Spartina (and perhaps other species) between Sweetwater and Tijuana suggests that a reduced tidal range similar to that at Mugu Lagoon is present at Tijuana. There could also be differences in method between the two studies that are not apparent. Obviously, more research into this matter is needed. Zedler and Mauriello's (1979) production estimate of 2792 g m-2yr-1 for pure stands of Salicornia virgi ni ca at Los Penasquitos in 1978 is close to pure stand mean of 3062 g m-^yr-1 (SST) produced by this study. This level of production Los Penasquitos may not, however, be achieved every year for Zedler and Mauriello (1979) reported Salicornia virginica growth in July-August 1978 to be 2.4 times that of 1977 for the same period. They contend that greater rainfall and partial impoundment of runoff due to late spring entrance closure in 1978 are responsible for the disparity. This interpretation is open to question. I observed water levels in June 1977 to be-.4 m higher than in June 1978 (entrance closed at both times) and, while 1978 was indeed the wetter year, August 1977 was one of the wettest on record (NOAA 1977, 1978). This suggests that prolonged inundation of the marsh in late spring and summer 1977 held July-August production to an abnormally low level and that high production returned with the more favorable inundation-moisture balance of 1978. Because production estimates of Eilers (1979), Hoffnagle et a]_. (1976) and those of this study are based on nearly identical methodology, some 53 ------- Table 15. Net Production for Salt Marshes Along the Pacific Coast of North America (g m-2yr-1) Source Locale Production Method Burg et aK (1975) Puget Sound 750a, 90-1400b Max.-min. live standing Washington a h Eilers (1979) Nehalem Bay 1400 , 227-2800° SST9 Oregon Hoffnagle et al_. (1976) Coos Bay 380-1100° SST Oregon r r Cameron (1972) San Francisco Bay 1200-1700 Peak live standing crop California Mahal 1 and Park (1976a) San Francisco Bay 960C, 690C Peak live standing crop California k This Study Bolsa Bay 2494 (2368)a SSTC (SST) California Upper Newport Bay 2150 (2034)a California Los Penasquitos Lagoon 3787 (3539)a Cali fornia Sweetwater River Estuary 3196 (2943)a California Zedler and Mauriello (1979) Los Penasquitos Lagoon 2792C Increase in live + increase California in dead standing crop Mission Bay 544C Cali fornia H a f Tijuana River Estuary 832°, 971 , 944 SST k Marsh mean Community means ^ Salicornia virqinica mean Spartina~~fol losa mean e f 9 Middle marsh mean High marsh mean Method of Smalley (1959) applied to species with summation of species production. SST corrected for losses due to disappearance of dead material. ------- observations on latitudinal trends in production along the Pacific Coast are- possible. I suggested earlier (EiTier's 1979) that salt marsh production might be expected1 to decrease with decreasing latitude as summer aridity increases soil salinity. While maximum soil salinity, in Oregon marshes (Eilers 1975) is 3 to 10 times less than that observed in this study, net production based on marsh means is 1.5 to 3.0 times greater in southern California. It appears that summer drought and increased soil salinity at lower latitudes are more than compensated for by the warm temperatures and high _light levels that promote a year-long growing season. But these observations are" tentative at best. Clearly, more work and a convergent methodology are needed before latitudinal trends in production along this coast can be firmly-established. Turner (1976) reviewed: and', in some cases, recalculated estimates, of macrophyte production in salt marshes of the Atlantic and Gulf Coasts and observed an increase in production with decreasing latitude. Comparsion of estimates recalculated by the Smalley (1959) method with those of this study suggest that marsh production in southern California is close to, if not greater than, that of similar latitudes. For example,, net production of tall Spartina alterniflora in Mississippi is 1964 g m-2yr-x (de la Cruz 1974 in Turner_ 1976); the ST mean for all pure^ stands of Spartina foliosa sampled at Sweetwater and Newport is 2051 g m-2yr-1. Kirby and Gosselink (1976) estimated net production of Sparti na alterni f1ora on creek banks and inland sites in Louisiana coastal marsh at 2645 and 1323 g: m-2yr-1, respectively, using the method of Wiegert and Evans (1964). The comparable SSTC mean for pure stands of Sparti na foliosa (2272 g m-2yr-1) is near the creek bank value, but mean production for this study based on SSTC for all macroplots (3135 g m-2yr-i) is greater than both figures. Hopkinson et ah (1978) studied pro- duction in seven marsh: macrophytes in Louisiana by the Wiegert and Evans method. Mean production in pure stands of Salicornia virginica at Los Penasquitos (SSTC = 2789 g m-^r-1) is- nearly equal to that of Distich!is spicata; greater than Phragmites communi s, Sagittaria falcata, Spartina al term flora and Sparti na cynosuroides; but less than half that of Spartrna patens. That the high level of salt marsh production reported for low latitudes on the Atlantic Gulf Coasts is duplicated in southern California marshes, supports the universality of a latitude-production gradient. The Spartina Question Sparti na fol iosa dominates . low marsh environments from northern California (Humboldt Bay) to the southern most extent of salt marsh at Laguna Ojo de Liebre, Baja California (Phleger 1965, Macdonald 1967). A tall (1 m) rhizomatous grass with prominent aerenchyma tissue, Spartina foliosa is capable of withstanding long submergence (Purer 1942). Macdonald 0~977) recognizes two distinct groups of estuaries and coastal lagoons in southern California based in part on the presence of this grass. The first of these is characterized by having deep channels, large tidal prism, perennial ocean contact and well-developed, pure stands of Spartina foliosa directly above mudflat. The second group includes those with insufficient tidal prism to prevent seasonal or long-term closure of their ocean inlets. Invariably, according to Macdonald (1977), Spartina foliosa is absent from the second group. The results of this investigation do, for the most part, support 55 ------- Macdonald's observation; vigorous stands of Spartina foliosa were present at Newport and Sweetwater; Sparti na foliosa was absent at Los Penasquitos. But, presumably, the tidal prism at Los Penasquitos was once greater for Purer (1942) reported not only the' presence of Sparti na foliosa there, but that it was. more luxuriant than elsewhere, twice as tall, greener and stiffer and less subject to being matted, and becoming blown down. The restricted distribution of Spartina foliosa at Mugu Lagoon where tidal fluctuation is reduced (Warme 1971), and its absence from diked marsh at La Ballona Creek (Clark 1979), lends further support, to the Macdonald (1977) model. The occurrence of Spartina foliosa at Bolsa where tidal fluctuation has not been permitted since 1899 is, therefore, difficult to explain. Perhaps the unique environment created by artifical removal of tides is a factor. Yet, because the salinity regime and soil alkalinity at BB-3, 4, 5, where: this grass was sampled were characteristic of sea water, and because elevations there were well below MHW, it is likely that some sea water inflow through the permeable beach sands occurred and thus permitted Spartina, which was probably present in the bay before 1899, to persist. The answer to this question, however, may never be known, for with the return of partial tidal fluctuation to Bolsa in November 1978, Spartina foliosa sites were drowned and the most plants deceased. Effects of Longterm Removal of Tidal Access—Bolsa Bay Vegetation and environmental measurements together suggest that the absence of tidal fluctuation for 80 years strongly influenced but did not totally alter the salt marsh system of Inner Bolsa Bay. Net production of vascular plants, except for Spartina at.macroplot 5 which appeared to be dying out as the study progressed, is comparable to that observed elsewhere. Negative redox potentials and attendant anaerobisis were among the more significant effects of diking and removal of the tides. Peat accumulations 15 to 20 cm thick in each macroplot indicated poor nutrient turnover and restricted nutrient contribution to the adjacent mudflat and channel. Yet, nitrogen, which has been shown to be a limiting factor in other salt marshes (Valiela et aL 1975) did not appear to be limiting during the sampling period at Bolsa or at the other three study sites. Comparison of the vertical range of salt marsh vegetation at Inner Bolsa with that of Outer Bolsa and the other southern California salt marshes included in this study (Figure 13) identified what appears to be the major alteration resulting from the removal of tidal flucutation. Apparently, in the 80 year absence of periodic inundation, salt marsh plants abandoned positions at or above MHW and re-established at anomalously low elevations. Frankenia grandif1ora, for example, was located over 1.0 m below its normal elevation and .25 m below the lowest Spartina foliosa or Salicornia virqinica found elsewhere. Yet, this anomalous condition may not be due to the removal of tidal fluctuation alone but a combination of tidal removal and subsidence (resulting from oil or ground water withdrawls or both). Moffatt and Nichol (1971) studied bench mark levels for the time period 1933 to 1964 and estimated subsidence at between 23 and 46 cm. Orange County bench marks along the west side of Inner Bolsa have been repeatedly surveyed and show continued 56 ------- loss of elevation. For example, bench mark IJ-29-68 near the sampling transect descended by 8.4 cm between 1968. and 1976. From the available data, a mean subsidence rate for Inner Bolsa may be estimated at about 1 cm per year. Subsidence, then, could account for a marshland shift downward of approx- imately 80 cm since the removal of tidal fluctuation and, together with some re-establishment or vegetation extension of marsh plants to lower levels, may be responsible for the anomaly. Whatever the cause, however, it is obvious that restoration of unrestricted tidal access to Inner Bolsa (as with a new channel to the Pacific Ocean which is under consideration) will lead to pro- longed inundation and destruction of some existing salt marsh.1 1 Following the construction of a parking lot for visitors and a new dike to prevent inundation of land owned by Signal (Figure 5), partial tidal contact as mentioned above was returned to 52 ha of Inner Bolsa by removing flap valves on culverts through the old dike. The marsh is now (August 1979) in an advanced state of decay and, due to the restricted nature of the culverts, water fluctuation is limited to about .5 m above -.75 MHW. 57 ------- LITERATURE CITED Adams, D.A. 1963. Factors influencing vascular plant zonation in North Carolina salt marshes. Ecology 44:445-456. Banwart, W.L., Ml A. Tabatabai, and^ J.M. Bremner. 1972. Determination of ammonium in soil extracts and water samples by an ammonia electode. Com- munications in Soil Science and Plant Analysis 3:449. Behrens, E.W. 1965. Use of the Goldburg refractometer as a salinometer for biological and geological field work. Journal of Marine Research 23:165-171. Bradshaw, J.S. 1968. Report on the biological and.ecological relationships in the Los Penasquitos Lagoon and salt marsh area of the Torrey Pines State Reserve. State Department of Parks and Recreation Contract 4-059-033. Bradshaw, J.S., and P.J. Mudie. 1972. Ecology of Los Penasquitos Lagoon. "In C.L. Hubbs ant T.W. Whitaker, editors. Torrey Pines State Reserve. Torrey Pines Association, La Jolla. Brereton, A.J. 1971. The structure of the species populations in the initial stages of salt-marsh succession. Journal of Ecology 59:321-338. Browning, B.M., and J.W. Speth. 1973. The natural resources of San Diego Bay: Their status and future. State of California Department of Fish and Game, Coastal Wetland Series No. 5. California Coastal Zone Conservation Commission. 1975. California coastal plan. Sacramento, Califonia. Carpelan, L.H. 1969. Physical characteristics, of southern Califonia coastal lagoons. Pages 319-334 i_n A.A. Castanares and F.B. Phleger, editors. Coastal lagoons, a symposium (UNAM-UNESCO), Instituto de Biologia, Universidad Nacional Autonoma de Mexico, Mexico City. Chapman, V.J. 1976. Wet coastal formations. Elsevier Publishing Company, Amsterdam, The Netherlands. Clark, J. 1974. Coastal ecosystems. Conservation Foundation, Washington, D.C. . 1979. BalTona wetlands study. Part I. Report to School of Architecture and Urban Planning. University of Califonia, Los Angeles. 58 ------- Cooper, A.W; 1974. Salt marshes. Pages 55-98 m H.T. Odum et aK , editors. Coastal ecological systems of the United States, II. Conservation Foundation, Washington, D.C. Darby, R. 1964-. The last chance lagoon. Westways 56:30-31. de la Cruz, A. A. 1973. The role of tidal marshes in teh productivity of coastal waters. Bulletin Association of Southwest Biologists 20:147-156. Dillingham Environmental Company. 1971. An environmental evaluation of Bolsa Chica area. Vol. I-III. Dillingham Corporation, La Jolla, California; Earth Science Associates. 1971. Chula Vista bayfront study, geotechnical planning investigation. Palo Alto, California. EDAW Inc. (Environmental Planners). 1978. Draft report to the Bolsa Chica study group. Eilers, H.P. 1975. Plants, plant communities, net production and tide levels: The ecological biogeography of the Nehalem salt marshes, Tillamook County, Oregon. Doctoral thesis. Oregon State University, . 1976. The ecological biogeography of an Oregon coastal salt marsh. Yearbook Association of Pacific Coast Geographers 38:19-32. 1979. Production ecology in an Oregon coastal salt marsh. Estuarine and Coastal Marine Science 8:399-410. Ford, R.F., A. Bradon, and M.V. Needham. 1971. Marine algae, grasses, invertebrates, and fishes of the Sweetwater River and Paradise Creek marshes and the potential ecological effects of the Sweetwater flood control channel. Sea Science Services Technical Report No. 3. Frey, W.W., R.F. Hein, and J.L. Spruill. 1970. The natural resources of Upper Newport Bay and recommendations concerning the bay's development. California Department of Fish and Game, Coastal Wetland Series No. 1 Gause, G.F. 1934. The struggle for existence. Williams and Wilkins, Baltimore. Good, R.E. 1972. Salt marsh production and salinity. Bulletin Ecological Society of America 53:22 (abstract). Heinle, D.R., and D.A. FTemer. 1976. Flows of materials between poorly flooded tidal marshes, and an estuary. Marine Biology 35:359-373. Henrickson, J. 1976. Ecology of southern California coastal salt marshes. Pages 49-64 i_n J. Latting, editor. Plant communities of southern California. California Native Plant Society, Special Publication No. 2. 59 ------- Hesse, P.R. 1972. A textbook of soil chemical analysis. Chemical Publishing Co., New York. Hoffangle, J.,, et aK 1976. A comparative study of salt marshes in the Coos Bay estuary. National Science Foundation Student Originated Study. Hopkinson, C.S., J.G. Gosselink, and R.T. Parrondo. 1978. Above-ground production of seven marsh plant species in coastal Louisiana. Ecology 59:760-769. Inman, D.L., and C.E. Nordstrom. 1978. Opening of coastal lagoons by sand fluidization. University of California Sea Grant College Program Annual Report 1976-1977. Kirby, C.J., and J.G. Gosselink. 1976. Primary production in a Louisiana Gulf Coast Spartina alternif1ora marsh. Ecology 57:1052-1059. Macdonald, K.B. 1967. Quantitative studies of salt marsh mollusc faunas from the North American Pacific Coast. Doctoral thesis. University of Calfiornia, San Diego. . 1977. Coastal salt marsh. Pages 263-294 ijvM.G. Barbour and J. Major, editors. Terrestrial vegetation of California. Wiley, New York. Macdonald, K.B., et al_. 1971. Changes in the ecology of a southern California wetland removed from tidal action. Second Coastal and Shallow Water Research Conference (abstract). University of Southern California, Los Angeles. Mahall, B.E. 1974. Ecological and physiological factors influencing the ecotone between Sparti na foliosa Trin. and Salicornia virginica L. in salt marshes of northern San Francisco Bay. Doctoral thesis. University of California, Berkeley. Mahall, B.E., and R.B. Park. 1976a. The ecotone between Sparti na foliosa Trin. and Salicornia virginica L. in salt marshes of northern San Francisco Bay: I. Biomass and production. Journal of Ecology 64:421-433. . 1976b. The ecotone between Sparti na foliosa Trin. and Salicornia virginica L. in salt marshes of northern San Francisco Bay: II. Soil water and salinity. Journal of Ecology 64:793-809. . 1976c. The ecotone between Spartina foliosa Trin. and Salicornia virginica" L. in salt marhses of northern San Francisco Bay: III. Soil aeration and tidal immersion. Journal of Ecology 64:811-819. Milner, C., and R.E. Hughes. 1968. Methods for the measurement of the primary production of grassland. IBP Handbook no. 6. Blackwell Scientific Publications, Oxford. 60 ------- Moffatt and Nichol, Engineers. 1971. Historic tideland investigation of Bolsa Chica and Anaheim Bays. Orange County, California. Mudie, P.J. 1970a. Ecology of the Sweetwater River tidal wetlands. Pre- liminary report for the Cliula Vista Planning Department. . 1970b. A survey of the- coastal wetland vegetation of San Diego Bay. Parts I and II. Report for the California Department of Fish and Game. Mudie, P.J., B. Browning, and J. Speth. 1974. The natural resources of Los Penasquitos Lagoon and recommendations for use and development. State of California Department of Fish and Game, Coastal Wetland Series No. 7. Munz, P.A. 1974. A flora of southern California. University of California Press, Berkeley, California. Odum, E.P., and A.A. de la Cruz. 1967. Particulate organic detritus in a Georgia salt marsh-estuarine ecosystem. Pages 383-388 iji G.H. Lauff, editor. Estuaries. American Association for the Advancement of Science Publication 53. Odum, W.E., J.C. Zieman, and E.J. Helad. 1972. The importance of vascular plant detritus to estuaries. Pages 91-114 iji R. Chabreck, editor. Coastal marsh and estuary management symposium. Louisiana State University, Baton Rouge. Orion Research Incorporated. 1978. Instruction manual platimum redox electrode model 96-78. Patrick, W.H. Jr., and R.D. Delaune. 1976. Nitrogen and phosphorus utilization by Spartina alterniflora in a salt marsh in Barataria Bay, Louisiana. Estuarine and Costal Marine Science 4:59-64. Phleger, F.B. 1965. Sedimentology of Guerrero Negro Lagoon, Baja Califonria, Mexico. Papers Colston and Research Society 17:205-237. Pugh, J.C. 1975. Surveying for field scientists. University of Pittsburgh Press, Pittsburgh, Pennsylvania. Purer, E.A. 1942. Plant ecology of the coastal salt marshes of San Diego County, California. Ecological Monographs 12:81-11. San Diego Unified Port District Planning Department. 1972. Natural physical factors of the San Diego Bay tidelands. San Francisco Bay Conservation and Development Commission. 1969. San Francisco Bay plan. Sacramento, California. Smalley, A.E. 1959. The role of two invertebrate populations, Littorina irrorata and Orchelimum fidicinium- in the energy flow of a salt marsh ecosystem. Doctoral thesTT! University of Georgia, Athens. 61 ------- Snedecor, G.W. and: W.6. Cochran. 1967. Statistical methods. Iowa State University Press, Ames,. Iowa. Speth, J. 1970. California coastal wetlands inventory, 1969-70. Preliminary report to the California. State Department of Fish and Game. Steever, E.Z. , R.S. Warren, and W.A. Niering. 1976. Tidal energy subsidy and standing crop production of Spartina alterniflora. Estuarine and Coastal Marine Science 4:473-478. Stevenson, M. 1978. Draft working paper Upper Newport Bay. Los Angeles/ Orange County Regional Coastal Wetland Workshop, California Coastal Commission. Stevenson, R.E. 1954. The marshlands at Newport Bay (California). Doctoral thesis. University of Southern California, Los Angeles. Stevenson, R.E. and K.O. Emery. 1958. Marshlands at Newport Bay, California. Allen Hancock Foundation Publication, Occasional Papers 20:1-109. Stock, M.W. 1972. Biological studies on Saldula palustris (Douglas) with emphasis on factors influencing wing pigmentation (Heteroptera: Saldidae). Doctoral thesis. Oregon State University, Corvallis, Oregon. Stolzy, L.H. and H. Fluhler. 1978. Measurement and prediction of anaero- biosis in soils. Pages 363-425 J_n D.R. Nielsen and J.G. Macdonald, editors. Nitrogen in the environment. Vol. 1. Nitrogen behavior in field soil. Academic Press, New York. Teal, J.M. 1962. Energy flow in the salt marsh ecosystem of Georgia. Ecology 43:614-624. Turner, R.E. 1976. Geographic variation in salt marsh macrophyte production: A review. Marine Science 20:47-68. Tyler, G. 1967. On the effect of phosphorus and nitrogen supplied to Baltic shore meadow-vegetation. Bot. Notiser 120:433-447. 1971. Distribution and turnover of organic matter and minerals in a shore meadow ecosystem. Oikos. 22:265-291. U.S. Army Corps of Engineers. 1976. Sweetwater River flood control channel, State Highway Route 54, Interstate Route 5, ceqreation facilities, and conservation of wetlands. U.S. Army Engineer District, Los Angeles, California. U.S. Department of Interior. 1972. Southern California estuaries and coastal wetlands, endangered environments. Bureau of Sport Fisheries and Wildlife, Portland, Oregon. 62 ------- Valiela, I., and J.M. Teal. 1974. Nutrient limitation in salt marsh vegetation. Pages 547-563 ia R.J. Reimold and W.H. Queen, editors. Ecology of halophytes. Academic Press, New York. Valiela, I., J.M. Teal, and W.J. Sass. 1975. Production and dynamics of salt marsh vegetation and the effects of experimental treatment with sewage sludge. Journal of Applied Ecology 12:973-982. Warme, J.E. 1971. Paleocological aspects of a modern coastal lagoon. University of California Publications in the Geological Sciences No. 87. Wiegert,, R.G., and F.C. Evans. 1964. Primary production and the disap- pearance of dead vegetation on an old field in southeastern Michigan. Ecology 45:49-63. Winfield, T.P. and J.B. Zedler. 1976. Comparative productivity of salt marsh vegetation and in the Tijuana Estuary (southern California). Paper presented at 57th annual meeting, of the Western Society of Naturalists. Fullerton, California. Zedler, J.B., and D.A. Mauriello. 1979. Coastal wetland management. Effects of disturbance on estuarine function. University of California Sea Grant College Program Annual Report 1977-78. 63 ------- Appendix A. Macroplot living and dead standing crop biomass (g m-2). Marsh Macroplot Living Biomass Dead Biomass Harvest Session Harvest Session 1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 1955 1377 680 1327 2093 1725 1379 829 971 789 2056 1752 1248 1374 2 678 390 269 438 771 762 369 123 107 113 68 250 234 186 3 682 1185 650 1189 1512 1565 1534 967 1945 1616 1250 2371 1558 1230 4 555 1059 239 544 476 1136 754 114 574 297 622 593 700 641 5 462 1023 215 337 486 968 867 860 643 386 712 990 904 525 6 999 476 759 735 1313 1238 1211 700 1516 822 967 1518 780 1428 7 365 619 236 344 739 529 1461 154 510 247 563 1190 655 1148 a 489 566 181 705 1385 1095 1545 193 895 71 507 1458 987 895 9 1737 525 446 709 777 688 526 505 438 406 300 807 636 446 10 227 534 503 510 729 738 280 159 358 510 238 280 786 397 11 702 980 599 619 1158 1150 980 690 845 544 669 1018 652 1106 12 250 575 316 606 678 826 789 376 449 250 356 811 961 697 13 1008 456 857 962 1153 1391 921 667 915 771 757 1604 1496 1507 14 995 401 149 318 470 496 831 88 969 1309 213 606 453 385 15 188 85 47 195 204 293 376 157 297 167 72 164 326 232 16 660 539 426 431 322 443 387 33 92 102 194 263 167 55 17 845 1385 674 647 1186 173 1705 2097 1381 743 616 1301 1040 1435 18 845 687 254 180 896 455 807 466 1230 701 706 1360 603 664 19 715 973 894 1150 2840 2364 3430 2696 1548 2095 1269 1728 1159 2204 20 527 778 865 1511 1193 914 910 545 297 631 461 678 562 401 21 832 552 383 673 590 590 999 778 233 230 275 375 379 661 22 1072 586 564 743 1169 963 1097 743 697 486 1039 941 1095 1183 23 374 146 347 523 1419 1362 887 85 196 134 197 388 449 397 24 736 297 608 579 1012 797 724 709 326 450 138 699 375 599 25 218 900 333 1300 1902 1190 845 211 225 407 497 266 381 649 26 185 78 174 810 629 723 322 0 147 181 206 285 267 246 27 462 438 420 745 1094 1042 654 302 460 333 803 364 502 364 SRE continued ------- Appendix A. cont. Marsh Macroplot Living Biomass Dead Biomass 1 2 Harvest Session 3 4 5 6 7 1 2 Harvest 3 4 Session 5 6 7 SRE 28 861 349 417 602 824 563 631 261 472 383 1319 796 409 552 29 45 455 99 553 474 233 120 198 300 111 378 186 478 153 30 552 589 259 1033 579 515 831 221 363 102 643 439 137 448 31 790 417 225 439 427 1023 1043 72 173 159 269 150 559 296 LPL 1 2564 960 1325 583 1623 2258 1180 1247 834 1481 466 514 532 607 2 1164 1567 1127 722 1624 1744 1203 760 892 534 447 580 814 952 3 989 2983 1459 1059 1471 1734 1738 858 830 634 176 68 185 523 4 2509 1912 1421 514 1252 1467 1665 839 1017 560 243 1123 1110 743 5 1390 1213 1317 1556 1578 1435 2838 — 2469 1156 1942 2780 1669 6 831 2607 813 1991 2119 2308 2637 2786 2111 2566 2057 2634 3447 2079 7 2880 1767 1269 1488 1158 1584 2434 839 1498 1557 1229 1091 1149 1281 8 502 274 202 213 583 663 598 4183 4552 2696 2345 4543 4749 2872 9 1181 853 467 654 1038 1625 1556 1940 2864 2133 1687 2049 2904 2556 10 2323 1228 425 1041 1040 1082 2050 1091 1677 419 475 762 1012 646 11 3303 1993 1548 2597 2965 2031 1858 806 836 1280 575 887 3713 2421 12 1269 58 802 1067 920 574 484 2197 3336 2008 2507 2159 2010 2177 13 45 10 0 24 0 1 21 1036 1508 845 1409 715 642 762 14 1164 746 945 882 393 1199 538 1688 1137 1017 964 855 1329 1262 15 3915 1931 1206 1898 1949 1787 946 1523 1901 856 1800 1458 1802 988 16 1003 625 476 411 1750 1390 1292 1501 1620 487 917 484 1402 2134 17 457 1306 1050 1180 353 808 599 1647 1603 1963 989 1367 1374 1675 18 3238 3241 703 1242 1605 2225 1916 1272 1774 830 1965 770 1535 1445 19 1308 718 780 1091 1061 1783 1684 1613 2860 1832 2142 1500 1383 2033 20 1009 1256 1003 657 729 2391 1143 1303 1029 1353 1483 657 868 1416 21 551 938 731 960 1018 1276 1214 1073 1043 824 597 798 1066 840 continued ------- Appendix A. cont. Marsh Macroplot Living Biomass Dead Biomass 1 2 Harvest Session 3 4 5 6 7 1 2 Harvest 3 4 Session 5 i 6 7 1 908 1023 414 569 1178 487 573 365 401 352 316 222 345 346 2 636 418 325 762 922 587 552 486 412 304 331 656 219 313 3 597 922 556 954 1231 1004 1056 236 491 254 403 533 329 352 4 623 382 358 620 711 667 556 349 341 325 228 1075 561 574 5 464 395 464 425 315 789 665 357 539 504 814 790 898 638 6 854 221 139 288 503 294 756 502 966 834 1125 1049 895 683 7 263 356 172 585 360 670 426 750 573 393 314 595 890 557 8 553 538 297 919 1554 795 1070 162 586 171 770 762 656 469 9 211 349 341 714 858 717 425 216 45 83 183 129 403 223 10 878 355 315 629 769 948 467 554 364 342 405 944 929 737 11 243 206 411 692 1177 814 420 147 96 106 114 456 243 271 12 493 833 718 863 662 511 377 301 491 253 327 634 713 470 13 1679 181 139 301 398 687 561 267 637 495 1134 1218 922 807 14 292 546 318 624 973 808 889 454 389 227 239 230 48 260 15 225 436 234 590 656 559 739 416 511 138 127 534 183 263 16 15 50 82 385 524 347 421 334 207 116 204 98 36 145 17 591 429 186 279 666 784 724 345 293 119 0 388 236 434 18 645 423 327 1156 1035 860 1140 321 136 141 253 457 493 435 19 257 175 94 310 520 425 212 72 196 92 171 92 142 243 20 685 221 71 379 241 377 547 326 845 738 696 1195 856 784 21 1075 449 481 447 369 683 593 473 354 331 501' 558 367 304 22 115 156 152 528 855 789 866 208 151 137 130 48 97 171 23 728 604 210 544 191 813 339 1137 1184 625 1072 598 1440 865 24 870 734 209 719 245 736 1294 570 417 145 917 355 985 1456 25 614 266 104 457 338 295 349 610 958 322 694 1491 1194 998 UNB continued ------- Appendix A. cont. Marsh Macroplot Living Biomass Dead Biomass Harvest Session Harvest Session 1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 149 1633 642 956 2059 1563 1270 927 732 143 1088 1233 873 1467 2 628 622 274 969 709 662 630 784 495 411 505 445 608 887 3 598 349 135 817 639 474 519 1046 411 320 380 1083 938 1602 4 423 28 4 61 37 203 0 1231 770 208 702 295 1096 578 5 16 50 2 0 0 0 0 62 51 2 72 16 34 62 BB ------- Appendix B. Net Production for Plant Species in Macroplots (g m-^y-1) Bama Crtr Cusa Oisp Frgr Juca Lica Lose Moli Coma Sabi Savi Spfo Suca Trma 1 3445 131 2 137 342 88 998 121 103 3 6 1357 1 3138 391 4 107 404 2 1 2167 130 5 175 504 1435 6 1147 43 1811 33 18 7 68 47 422 10 49 2814 3 47 8 209 238 4 1349 136 204 1 2218 15 82 80 9 70 549 127 246 1804 7 99 10 40 80 206 65 122 554 33 409 11 221 504 550 1249 12 176 718 12 82 942 1 29 13 2 315 542 10 575 562 892 43 67 14 1824 15 620 16 81 12 284 366 517 5 57 17 160 415 3 3732 3 18 2659 19 6231 20 955 320 4 1319 33 21 841 862 1 482 179 197 22 980 28 698 245 1258 882 23 779 114 713 869 26 24 420 18 99 34 263 208 55 926 168 7 25 129 114 2395 272 153 345 26 3 15 5 1 632 156 792 27 375 263 845 60 355 22 98 383 25 28 28 1426 68 169 7 25 663 93 29 20 4 476 273 45 376 30 95 24 381 458 1122 545 continued ------- Appendix B. cont. Site Bama Crtr Cusa Disp Frgr Juca Lica Lose Moli Coma Sabi Savi Spfo Suca Trma LPL UNB 1 5011 2 2088 3 3155 4 3067 5 1831 1905 6 4864 574 7 2287 8 250 1184 2962 9 3175 1994 10 3056 U 5303 12 4 4240 1176 13 1767 14 2690 15 5848 16 3224 17 2047 18 5219 19 2574 1370 20 2417 21 1582 1 357 1351 2 5 12 348 892 8 295 3 72 64 112 154 403 833 333 4 222 1 414 1 216 5 231 407 747 6 7 401 5 999 8 58 239 175 21 816 1182 1 443 9 26 43 16 470 123 466 125 10 205 1561 94 44 10 312 20 790 31 663 95 1339 142 85 511 52 235 continued ------- Appendix B. cont. Site Bama Crtr Cusa Disp Frgr Juca Lica Lose Moli Coma Sabi Savi Spfo Suca Trma 11 36 162 18 554 6 103 323 9 388 12 75 780 27 96 3 1 799 261 13 2621 14 620 33 491 149 1077 15 75 184 6 4 1048 16 185 27 40 13 579 98 25 17 509 34 340 387 18 437 202 203 74 1203 55 65 19 7 13 51 151 61 40 179 49 334 20 14 32 10 1320 21 43 5 77 4 198 97 923 382 325 22 58 8 7 499 72 101 206 95 274 23 3217 24 320 3160 50 16 25 320 1969 1 74 4564 2 1178 1120 3 1452 72 1525 262 4 459 1032 5 164 ------- Appendix C.l. Salinity of Substrate at 0 to 5 cm (ppt). Marsh Harvest Session Marsh Harvest Session 1 2 3 4 5 6 7 1 2 3 4 5 6 7 SRE 1 41 42 48 47 48 LPL 1 80 16 15 11 36 2 48 50 35 52 64 52 2 104 27 22 11 25 3 38 41 20 48 58 45 3 66 16 12 10 4 52 41 33 53 65 61 4 92 22 10 27 5 53 51 36 50 60 60 5 64 108 14 11 6 41 42 22 30 52 55 52 6 93 8 12 11 32 7 55 50 37 42 56 58 7 48 44 21 20 15 30 8 61 51 56 58 60 8 18 9 61 42 64 72 75 9 20 10 67 60 36 105 72 70 10 102 20 7 28 11 59 58 96 72 75 11 85 15 10 15 12 55 54 72 75 12 13 13 45 44 26 50 64 13 62 40 31 46 15 38 14 43 40 34 38 40 44 44 14 101 30 16 15 106 121 42 78 96 96 15 79 22 16 11 23 16 44 48 33 54 62 60 16 97 26 15 8 17 52 50 34 49 68 62 17 125 15 10 18 47 43 28 32 40 44 40 18 42 67 20 14 10 27 28 19 48 38 25 62 19 102 14 12 20 41 44 28 48 54 62 53 20 94 16 13 21 48 50 27 38 62 68 60 21 115 29 10 22 43 40 24 42 60 57 49 23 47 44 35 50 46 58 55 UNB 1 44 15 41 24 42 45 26 40 53 55 56 2 49 10 11 90 25 54 43 28 44 48 58 55 3 59 9 28 40 58 42 50 26 60 45 28 45 46 60 60 4 39 26 23 37 46 46 43 27 42 45 28 42 45 58 54 5 41 27 25 33 43 35 43 28 41 45 31 42 56 60 56 6 35 20 24 30 37 40 41 29 41 45 31 42 56 64 56 7 55 30 44 44 31 40 45 64 55 8 45 5 5 34 64 44 64 31 44 41 30 40 42 52 48 9 42 22 28 35 54 50 52 continued ------- Appendix C.1. cont. Marsh Harvest,Session Marsh Harvest Session 1 2 3 4 5 6 7 UNB 10 40 18 24 32 41 44 44 11 47 22 24 37 48 50 41 12 40 22 22 34 60 50 47 13 38 29 37 36 42 38 37 14 60 44 34 64 77 76 70 15 55 44 34 55 82 85 81 15 55 44 34 55 82 85 81 16 55 43 35 56 83 91 83 17 61 57 35 48 56 68 61 18 45 41 31 42 61 51 48 19 42 25 29 40 60 63 52 20 37 37 31 35 40 40 38 21 40 28 27 41 45 38 22 41 26 24 40 52 51 47 23 36 25 22 34 37 36 36 24 40 27 30 34 40 49 42 25 37 27 30 35 40 38 35 1 2 3 4 5 6 7 1 22 7 10 7 20 28 45 2 30 10 13 13 30 34 36 3 37 29 16 27 35 48 38 4 38 33 34 35 48 45 44 5 39 33 27 47 54 44 BB ------- Appendix C.2. Salinity of Substrate at 45 to 50 cm (ppt). Marsh Harvest Session Marsh Harvest Session 1 2 3 4 5 6 7 1 2 3 4 5 6 7 SRE 1 43 42 40 47 48 LPL 1 26 50 47 25 20 2 52 53 45 44 49 60 2 60 25 25 3 49 53 42 50 51 3 40 50 21 25 12 4 55 50 50 47 55 55 4 51 44 20 20 5 55 50 49 48 47 48 5 39 70 21 25 6 63 44 42 50 54 6 71 32 17 7 57 53 44 36 43 61 7 26 81 41 22 25 10 8 70 59 44 36 51 56 8 64 9 77 62 54 42 54 60 66 9 10 71 72 61 61 10 64 11 93 70 55 61 62 11 75 41 12 67 68 70 60 64 12 13 60 50 36 49 62 13 55 51 36 44 54 60 14 54 42 42 35 38 40 40 14 56 55 15 95 102 102 98 82 104 105 15 24 55 14 28 22 16 50 61 49 44 49 58 60 16 58 52 68 17 53 40 47 39 60 55 17 66 55 62 18 44 40 35 36 40 40 18 28 37 55 19 50 38 30 27 44 42 48 19 58 20 40 50 42 49 45 46 49 20 63 55 21 42 54 46 44 45 58 52 21 69 54 64 22 50 50 35 45 42 48 52 23 58 48 53 36 49 51 61 UNB 1 52 37 3 48 24 55 51 42 38 38 50 55 2 48 41 22 30 40 48 25 45 48 41 40 42 62 55 3 44 36 21 25 32 36 45 26 45 50 45 48 48 58 62 4 44 37 42 32 35 40 46 27 46 53 37 42 40 53 56 5 43 36 32 30 32 39 40 28 48 39 44 44 42 48 48 6 36 32 33 42 36 36 48 29 60 48 39 42 43 57 58 7 49 32 4 50 30 48 46 36 42 38 62 54 8 54 39 18 27 22 43 34 31 42 42 37 40 32 41 42 9 49 37 34 32 48 59 55 continued ------- Appendix C.2. cont. ^arSli Harvest Session Marsh Harvest Session 1 2 3 4 5 6 7 UNB 10 40 37 34 32 33 42 44 11 45 37 33 44 55 52 12 40 33 25 36 45 50 48 13 38 37 34 37 40 35 14 67 65 69 64 68 15 72 67 70 78 60 65 16 63 65 63 62 66 60 17 53 68 56 64 62 18 51 52 46 45 44 48 44 19 60 51 42 54 58 62 20 38 38 39 40 34 30 21 43 34 26 50 45 22 44 41 40 32 40 43 46 23 35 35 28 32 35 34 37 24 38 35 36 32 36 40 48 25 36 35 29 30 38 34 1 2 3 4 5 6 7 1 22 22 19 22 20 25 2 20 27 29 31 35 36 3 34 31 35 35 41 35 29 4 41 34 39 35 45 32 42 5 36 36 40 36 48 47 38 BB ------- Appendix C.3. Salinity of Substrate Free-water (ppt), Harvest Session Harvest Session 1 2 3 4 5 6 7 1 2 3 4 5 6 7 SRE 1 40 47 20 48 46 50 LPL 1 32 50 33 9 2 55 50 34 47 44 55 60 2 54 40 12 15 3 48 40 28 47 48 50 3 56 26 6 19 26 4 52 43 38 40 50 50 4 51 33 16 10 27 5 46 45 30 34 42 48 50 5 56 20 10 10 20 6 43 40 24 49 50 6 61 28 16 6 7 52 44 29 40 47 47 7 35 32 16 15 26 20 8 54 50 36 45 58 60 8 24 9 62 45 42 54 65 66 9 29 25 10 57 61 26 60 68 62 10 54 16 15 65 11 58 52 26 72 65 11 65 20 10 16 20 46 12 61 54 37 70 54 12 31 13 35 40 22 47 52 13 51 35 5 10 55 62 14 37 40 33 36 40 40 14 51 24 22 18 48 15 94 72 103 102 15 32 45 33 8 13 16 34 16 48 48 44 47 54 58 16 54 41 28 16 60 70 17 40 43 37 17 62 57 34 15 18 55 62 18 38 37 31 40 40 18 25 35 23 3 25 16 19 45 37 27 42 19 55 28 25 20 25 20 55 44 27 38 51 54 52 20 54 26 12 17 52 21 55 45 31 38 50 58 60 21 61 32 8 22 60 22 50 39 28 42 40 48 50 23 50 44 30 35 45 57 60 UNB 1 3 3 34 24 52 44 27 37 48 52 54 2 46 10 12 48 48 25 52 42 30 45 55 56 3 39 14 18 23 44 48 26 50 43 32 50 57 55 4 42 39 30 30 40 44 27 50 43 30 43 54 52 5 42 36 25 28 38 42 28 43 45 42 38 42 45 6 35 19 22 30 34 36 34 29 48 43 30 46 53 50 7 5 3 30 50 40 38 46 54 52 8 40 24 11 11 45 31 42 37 30 34 40 40 42 9 45 39 32 32 50 52 continued ------- Appendix C.3. cont. Marsh Harvest Session Marsh Harvest Session 1 2 3 4 5 6 7 UNB 10 38 33 25 26 35 38 40 11 34 28 30 50 38 44 12 34 28 23 31 42 13 35 23 22 32 34 34 34 14 61 40 45 48 70 71 15 70 57 44 50 78 74 16 70 46 61 56 68 65 17 65 56 40 44 60 65 18 49 44 37 46 45 46 50 19 41 39 36 34 50 62 20 41 30 27 34 35 28 21 38 27 22 32 36 42 22 40 30 22 35 48 45 23 33 30 23 28 41 34 34 24 37 28 22 28 38 38 25 36 33 21 25 31 35 30 1 2 3 4 5 6 7 1 31 13 14 7 15 20 25 2 37 9 16 18 29 30 32 3 31 26 16 26 40 41 40 4 37 26 25 35 48 45 47 5 37 26 9 41 42 50 42 BB ------- Appendix C.4. Reaction (pH) of Substrate Free-Water by Harvest Session (Assume One Decimal Place). Harvest Session M . . Harvest Session 1 2 3 4 5 6 7 1 2 3 4 5 6 7 SRE 1 62 68 70 67 66 70 LPL 1 68 67 67 2 63 66 66 66 64 66 65 2 73 69 69 67 3 56 60 62 62 62 58 3 65 63 68 63 65 4 59 60 63 60 61 62 4 66 66 66 67 68 5 61 67 71 73 68 68 66 5 64 67 69 66 72 6 61 64 64 63 60 6 66 67 68 67 7 63 62 65 64 62 62 7 59 60 63 64 69 8 60 65 64 64 66 62 8 72 9 61 66 64 61 67 62 9 70 70 10 64 65 67 62 10 63 62 70 65 11 63 67 70 66 64 11 64 64 69 63 66 63 12 69 68 67 66 64 12 70 13 69 65 72 62 64 13 68 67 70 72 14 63 69 65 65 65 63 14 67 67 68 61 70 15 64 76 67 15 64 63 63 66 68 16 70 60 61 61 61 59 16 70 65 68 64 67 76 17 62 55 69 17 73 67 69 66 69 67 18 64 62 70 66 64 18 63 67 71 62 63 19 72 74 76 70 72 19 70 67 68 63 78 20 70 67 72 62 69 66 69 20 74 68 69 66 21 67 66 70 68 67 67 68 21 73 71 69 67 73 22 69 69 73 78 66 66 70 23 68 67 79 70 66 68 70 UNB 1 88 85 24 68 67 69 68 67 71 2 75 77 72 72 71 25 65 60 69 66 65 68 3 74 74 72 69 70 26 63 61 64 63 61 63 4 63 61 64 62 61 62 27 61 57 63 64 60 63 5 74 61 65 61 62 60 28 60 59 59 60 58 60 6 67 65 66 63 68 66 65 29 60 60 62 60 59 60 7 82 78 30 60 55 66 60 57 62 8 70 74 73 70 69 31 63 59 66 69 65 67 64 9 62 63 64 67 62 62 continued ------- Appendix C.4. cont. Marsh Harvest Session Marsh. Harvest Session 1 2 3 4 5 6 7 UNB 10 62 62 63 61 68 59 70 11 63 62 62 66 12 65 66 67 65 64 13 64 69 68 68 68 70 69 14 61 64 63 66 63 61 15 60 60 64 61 61 57 16 60 60 62 61 62 65 17 67 61 68 63 59 52 18 57 57 62 55 59 60 57 19 63 61 63 63 63 63 20 67 66 67 66 69 65 72 21 61 64 63 63 66 61 22 61 63 62 61 62 68 23 68 64 72 64 65 65 24 61 64 75 80 64 62 25 68 68 68 71 66 65 64 1 2 3 4 5 6 7 1 74 70 72 70 69 72 68 2 77 77 74 69 69 71 71 3 79 73 75 70 68 72 72 4 71 73 69 70 73 68 72 5 80 78 76 72 74 72 74 BB ------- Appendix C.5. Ammonia in Substrate Free-Water (10-5 M). Marsh Harvest Session Marsh Harvest Session 1 2 3 4 5 67 1 2.3 4 5 6 7 SRE 1 9 1 24 9 60 LPL 1 11 4 7 2 15 1 3 9 5 9 2 4 1 7 25 3 4 1 15 6 29 3 9 1 5 54 19 4 12 17 2 10 9 66 4 4 1 7 41 41 5 23 5 22 21 34 25 5 4 1 6 22 23 6 17 1 7 15 6 29 1 8 64 7 6 15 1 10 20 7 11 3 19 55 230 8 11 1 20 20 12 8 2 9 18 1 41 6 13 9 2 10 10 8 3 6 8 10 42 2 17 39 11 5 1 10 14 11 6 2 6 20 52 27 12 2 9 14 12 1 13 13 3 7 10 13 10 4 20 54 14 36 111 11 5 20 14 2 3 6 18 18 15 13 2 15 1 2 8 24 35 16 15 1 11 15 7 16 6 3 5 39 33 17 24 14 18 17 8 3 5 41 42 18 10 11 12 16 18 10 2 5 25 42 19 36 1 10 6 19 1 1 5 43 22 20 30 1 24 11 6 23 20 1 3 6 28 21 30 1 9 4 5 7 21 3 6 6 380 28 22 24 14 1 15 8 4 9 23 60 10 1 4 5 6 9 UNB 1 7 3 24 60 10 1 15 4 4 5 2 21 2 8 8 6 25 40 13 1 3 4 7 3 22 2 4 38 4 26 34 18 1 3 6 5 4 41 16 6 19 5 5 27 34 18 1 3 9 6 5 16 32 3 12 17 6 28 5 12 1 3 8 9 6 580 440 105 66 320 102 25 29 19 17 1 344 7 2 25 30 7 17 1 3 3 7 8 18 2 4 10 5 31 9 17 1 19 20 290 7 9 12 3 6 14 12 6 continued ------- Appendix C.5. cont. |Yjars^ Harvest Session Marsh Harvest Session 1 2 3 4 5 6 7 UNB 10 12 4 3 15 18 9 6 11 7 4 9 16 26 12 24 3 3 18 36 13 105 42 26 132 360 640 77 14 96 7 3 47 6 18 15 45 12 15 55 8 20 16 105 26 88 75 65 59 17 100 3 210 134 35 6 18 22 5 4 6 30 17 4 19 11 4 3 56 20 8 20 25 26 21 32 54 5 6 21 26 5 7 19 7 3 22 15 3 3 24 6 8 23 108 8 13 33 130 66 26 24 45 6 5 30 6 8 25 120 13 6 14 54 49 87 1 2 3 4 5 6 7 1 43 30 15 8 42 24 67 2 39 5 3 4 7 32 550 3 72 3 3 6 10 56 94 4 730 4 36 88 64 860 610 5 75 6 11 78 17 690 95 BB ------- Appendix C.6. Redox Potential (Eh*mV) for Substrate Free-Water. Marsh Harvest Session Marsh Harvest Session 1 2 3 4 5 6 7 1 2 3 4 5 6 7 SRE 1 407 382 497 422 367 LPL 1 427 312 307 2 447 427 367 492 417 447 2 437 357 352 262 3 317 357 482 427 407 3 442 302 412 272 252 4 297 407 427 427 247 4 437 292 402 232 282 5 372 407 317 442 397 407 5 367 292 422 237 289 6 412 377 427 442 6 337 322 417 327 7 387 397 467 397 432 7 437 282 352 182 347 377 8 427 432 472 402 397 8 317 9 447 397 512 312 387 9 222 447 10 457 432 322 10 387 122 392 162 11 407 407 407 342 11 372 232 362 167 317 242 12 427 417 342 12 337 13 392 407 412 427 13 407 342 392 227 14 247 297 462 317 392 14 327 332 407 272 187 15 427 15 327 312 417 187 247 16 392 367 482 417 302 16 397 237 372 257 237 347 17 447 457 17 422 297 227 372 142 267 18 377 357 327 257 18 342 367 482 462 292 292 19 362 347 302 397 19 392 322 382 312 272 20 372 407 302 472 332 377 20 392 262 392 287 21 277 422 297 457 347 377 21 302 472 242 292 317 22 382 407 292 462 352 407 23 407 392 302 -18 367 347 UNB 1 422 382 24 447 422 467 372 392 2 342 357 337 387 247 25 447 427 467 402 297 3 317 357 262 377 372 26 397 447 477 392 307 4 347 360 247 397 367 267 27 397 442 477 87 347 5 262 364 187 397 177 397 28 442 447 467 467 417 6 -78 382 82 407 -113 -43 -43 29 327 447 472 387 427 7 512 127 30 432 442 472 387 402 8 297 462 337 412 31 197 307 257 472 352 359 9 197 392 362 387 259 292 continued ------- Appendix C.6. cont. Marsh Harvest Session Marsh Harvest Session 1 2 3 4 5 6 7 UNB 10 337 537 337 357 217 367 297 11 472 327 447 277 217 12 222 547 232 337 352 13 -63 442 -98 -23 -73 -38 -98 14 237 432 267 277 232 397 15 227 392 357 397 357 267 16 272 338 182 407 357 367 17 177 381 -98 257 259 342 18 347 412 172 337 257 397 257 19 217 376 212 407 447 387 20 -38 417 11 397 147 357 262 21 137 362 167 347 377 367 22 192 422 197 397 382 337 23 67 384 237 297 97 47 72 24 212 382 247 267 422 287 25 -43 369 237 182 219 307 267 1 2 3 4 5 6 7 1 147 342 127 87 277 122 357 2 212 289 22 137 57 42 322 3 47 288 -33 37 27 -23 12 4 -88 299 -126 -63 -43 -58 -73 5 7 317 7 -53 -53 -78 -53 BB ------- Appendix C.7. Water Content (Percent) of Substrate at 0-5cm. Marsh Harvest Session Marsh Harvest Session 1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 52 39 33 38 39 37 LPL 13 50 48 49 59 53 42 38 2 65 59 64 48 66 47 41 14 40 41 52 51 50 41 35 3 57 63 58 46 42 48 38 15 49 49 54 54 54 53 45 4 59 64 64 63 59 62 54 16 35 40 51 54- 51 39 31 5 56 53 53 56- 53 54 47 17 32 39 45 57 53 36 32 6 75 64 51 45 53 42 46 18 50 45 55 55 55 50 44 7 56 47 50 40 54 52 30 19 44 43 56 53 58 41' 35 8 42 49 42 35 38 42 20 32 34 50" 55 47 35 28 9 48 49 44 38 42 35 37 21 38 43 42 44 42 36 32 10 41 42 41 40 33 38 36 11 41 42 43 43 37 33 39 UNB 1 8 21 14 8 1 9 5 12 51 45 41 37 37 39 34 2 15 21 20 18 11 19 11 13 47 39 40 30 31 35 33 3 28 32 29 28 21 30 22 14 45 45 44 44 43 4 69 72 75 72- 69 69- 71 15 38 31 27 25 28 31 5 68 71 70 58 67 66 63 16 59 63 62 59 55 50 61 6 65 68 68 67 65 68 62 17 41 41 44 37 46 42 40 7 20 12 4 0 9 1" 18 47 47 49 47 46 45 48 8 29 32 25 19 30 22 19 38 43 32 40 30 31 37 9 76 72 68 65 74 69 20 64 61 55 51 65 52 50 10 73 65 71 67 66 64 21 51 48 49 48 58 49 61 11 77 71 74 68 68 68 22 57 59 47 47 52 53 12 57 53 64 43 53 45 23 66 64 69 63 69 68 45 13 70 64 43 62 63 63 24 70 74 53 56 60 56 51 14 69 74 71 43 68 71 69 25 54 64 64 69 66 66 65 15 73 76 75 75 68 72 67 26 51 67 67 68 63 62 64 16 75 76 76 75 69 70 69 27 64 61 65 61 63 41 61 17 65 73 72 75 65 69 69 28 55 59 61 59 56 55 55 18 72 77 80 78 72 77 78 29 56 59 57 58 58 56 55 19 69 73 71 72 65 68 67 30 44 57 52 56 52 52 50 20 69 68 69 70 71 72 68 31 50 42 40 41 41 44 38 21 69 71 73 68 65 66 66 22 63 66 67 66 62 62 66 1 49 41 63 63 69 57 33 23 62 63 64- 62 56 61 59 2 46 42 55 67 57 50 39 24 52 58 48 57 47 51 44 3 47 45 61 55 55 56 41 25 57 63 57 58 56 53 56 4 59 51 68 59 60 48 26 5 49 48 53 54 62 51 38 BB 1 42 50 37 78 64 46 51 6 51 56 63 54 57 47 43 2 78 80 83 73 60 73 78 7 51 57 57 61 61 55 52 3 85 86 89 77 86 85 86 8 27 13 40 35 33 22 20 4 74 80 82 72 79 80 9 28 41 33 34 20 17 5 76 65 82 89 79 75 77 10 55 60 58 57 50 44 11 54 55 58 66 66 61 49 12 27 22 33 37 37 21 10 82 ------- Appendix C.8. Water Content (Percent) of Substrate at 45-50 cm. Harvest Session Marsh Harvest Session 1 2 3 4 5 6 7 1 2 3 4 5 6 7 SRE 1 34 30 26 23 21 35 LPL 11 27 28 27 37 30 28 27 2 45 48 47 47 47 48 53 12 27 28 31 25 27 28 25 3 46 47 47 42 42 42 41 13 32 36 30 37 29 33 27 4 48 62 51 40. 56 47 29 14 29 30 18 33 34 28 29 5 50 56 52 55 54 51 56 15 30 31 31 35 34 25 33 6 30 34 37 40 30 3 V 32 16 28 28 27 31 30 30 27 7 32 36 32 46 31 31 31 17 27 28 25 28 29 27 27 8 30 30 31 20 28 29 56 18 40 40 40 43 42 39 40 9 33 33 34 30 32 28 30 19 21 27 21 38 23 26 28 10 32 31 31 27 29 28 28 20 22 29 27 28 30 45 29 11 25 32 26 26 27 28 30 21 27 21 26 31 29 29 30 12 27 26 27 25 24 27 24 13. 26 24 23 20 24 26 27 UNB 1 16 23 22 19 16 22 19 14 34 38 26 54 38 40 40 2 25 23 25 25 23 36 23 15 23 22 23 22 19 22 3 23 29 55 24 57 60 52 16 35 35 32 32 34 37 36 4 46. 45 48 59 47 44 30 17 42 47 33 33 43 46 42 5 61 51 50 70 67 29 45 18 47 45 47 47 47 44 57 6 52 56 54 54 52 55 55 19 44 41 40 45 41 39 7 20 22 10 19 20 18 20 56 57 59 57 56 56 54 8 32 65 25 56 62 61 21 53 56 54 45 56 47 52 9 34 24 27 29 23 24 22 49 50 50 49 49 48 47 10 29 26 31 25 30 22 23 51 50 58 50 52 36 67 11 22 23 23 23 29 21 24 53 52 65 36 35 29 37 12 23 27 33 21 23 20 25 65 54 54 52 48 53 51 13 42 39 24 39 29 32 26 68 55 47 53 49 48 51 14 40 22 23 22 31 43 27 50 55 55 52 49 67 49 15 20 21 20 32 21 21 20 28 32 54 52 50 54 51 50 16 57 21 29 39 21 22 20 29 37 44 39 44 51 41 48 17 21 47 24 33 20 20 30 50 38 45 40 44 38 45 18 35 38 34 36 26 29 25 31 38 56 56 42 47 38 42 19 23 21 21 20 22 21 19 20 22 26 26 30 23 24 24 LPL 1 19 ' 21 30 20 22 20 21 28 23 22 26 20 20 19 2 19 17 19 22 21 25 19 22 44 42 39 45 34 30 35 3 23 26 30 29 29 33 27 23 40 32 40 35 25 28 27 4 27 37. 36 45 31 35 31 24 51 56 46 54 39 43 54 5 36 37 40 42 40 42 33 25 28 33 31 34 30 31 31 6 22 38 27 38 32 35 32 7 42 45 44 46 47 46 46 BB 1 23 25 27 28 23 24 22 8 15 19 19 23 22 17 12 2 18 22 22 22 48 23 23 9 21 23 25 22 22 3 39 36 20 23 21 36 10 32 31 32 31 32 28 4 32 20 35 28 24 22 32 5 37 19 25 21 23 41 42 83 ------- Appendix C.9. Temperature (°G) of Substrate at 0-5 cm. Marsh, Harvest Session 1 21.5 2 22.0 3. 21.5 4 21.5 5 22.5 6 22.0 7 21.5 8 23.0 9 22.0 10 18.5 11 22.0 12 23.0 13 21.5 14 23.0 15 23.3 16 23.0 17 23.5 18 22.5 19 22.5 20 23.0 21 22.5 22 21.5 23 21.5 24 22.5 25 22.5 26 23.5 27 22.5 28 22.0 29 23.0 30 21.5 31 22.0 1 19.5 2 18.5 3 18.5 4 18.5 5 18.5 6 18.5 7 18.2 8 9 18.0 10 18.0 16.5 11.7 16.5 11.1 17.0 11.1 17.0 11.7 17.5 11.1 16.5 11.1 16.5 11.1 16.5 11.1 16.5 11.1 16.5 11.7 16.0 11.1 17.5 11.7 16.5 11.7 16.5 12.8 17.0 12.2 17.5 11.7 16.5 11.7 17.5 12.2 16.5 11.7 16.5 11.1 16.5 12.2 15.5 11.7 16.0 12.2 16.5. 11.7 16.5 11.7 16.5 12.8 16.5 12.8. 16.5 12.2 17.0 12.8 16.5 11.7 17.5 12.2 13.9 11.1 13.3 11.1 13.3 10.6 1.3.3 11.1 12.8 10.6 13.3 10.6 13.3 11.1 13.3 11.1 13.9 10.6 14.4 11.1 15.0 17.2 15.6 17.8 15.0 17.8 15.0 17.8 15.0 18.3 14.4 17.2 15.6 17.8 13.9 18.9 14.4 21.1 14.4 19.4 14.4 18.3 15.0 19.4 14.4 18.3 15.6 20.0 16.7 23.3 15.6 20.0 14.4 18.3 14.4 20.0 13.9 16.7 15.0 17.8 13.9 18.3 13.9 17.8 14.4 18.9 14.4 18.3 13.9 18.3 15.6 19.4 14.4 18.9 14.4 17.8 16.7 20.0 14.4 18.9 16.7 20.6 13.9 18.9 13.9 16.7 15.0 18.1 13.9 17.0 13.3 16.1 13.3 15.9 14.4 17.0 13.9 17.5 13.9 17.2 14.4 17.2 17.8 16.7 18.9 18.3 18.3 17.2 18.9 17.2 19.4 17.8 17.8 17.2 18.9 17.8 18.3 17.8 19.4 18.9 19.4 18.9 18.9 17.8 19.4 18.9 17.2 17.8 19.4 18.3 22.8 20.0 20.0 18.9 19.4 16.7 19.4 18.3 17.2 17.2 18.3 17.8 19.4 20.0 18.9 17.8 19.4 18.9 18.9 18.9 18.9 18.3 20.0 20.0 18.9 18.9 18.9 18.3 21.1 20.6 20.6 18.9 21.1 20.0 17.8 17.2 17.8 16.1 17.8 17.2 19.4 18.3 16.9 16.1 16.7 15.0 17.5 14.4 17.2 14.4 17.8 17.2 18.3 16.7 84 continued ------- Appendix C.9. cont. Marsh Harvest Session 1 2 3 4 5 6 7 LPL n 18.0 14.4 11.1 14.4 17.2 18.3 16.7 12 18.0 10.6 12.2 14.4 18.9 20.0 20.6 13 16.5 8.9 12.8 15.6 18.9 22.2 18.3 14 17.5 9.4 11.1 13.3 17.2 19.1 16.1 15 16.5 9.4 11.7 13.3 17.2 17.5 13.9 16 17.5 12.8 10.0 13.9 17.8 20.9 16.7 17 17.5 11.1 9.4 13.3 17.8 20.9 15.6 18 17.0 11.1 8.3 12.2 18.3 18.9 14.4 19 17.5. 11.1 11.1 13.3 19.4 18.0 14.4 20 17.0 10.0 11.1 13.9 18.3 19.4 16.1 21 17.0 10.0 9.4 14.4 18.3 17.8 14.4 UNB 1 22.0 13.3 11.7 13.9 22.2 19.4 19.4 2 20.0 12.2 11.7 13.9 20.0 20.3 17.2 3 20.0 12.8 11-. 7 13.9 20.0 19.7 17.2 4 20.0 13.3 12.8 14.7 18.9 18.0 17.2 5 19.0 1.2.8 12.2 15.3 18.9 19.4 16.7 6 19.0 13.3 13.3 15.3 19.4 19.7 16.7 7 19.0 12.2 11.7 15.0 20.6 23.3 27.8 8 18.0 12.8 11.7 13.3' 17.8 17.8 17.2 9 19.0 12.2 12.2 14.4 18.3 19.2 18.3 10 18.0 12.2 11.7 13.9 17.2 16.7 16.1 11 21.0 13.9 13.9 14.4 18.3 17.8 17.2 12 19.0 14.4 13.9 14.7 18.3 17.8 15.6 13 19.0 13.9 13.3 15.6 19.4 20.0 17.2 14 22.5 12.2 13.3 15.0 20.6 19.4 16.7 15 22.0 12.2 12.8 14.4 20.6 20.6 17.2 16 22.5 11.7 14.4 15.6 19.4 21.7 18.3 17 20.5 12.8 13.9 16.1 19.4 20.3 17.8 18 18.5 11.7 14.4 14.4 18.9 17.8 17.2 19 23.0 12.2 13.3 16.1 22.8 18.9 17.2 20 18.5 12.8 13.9 16.1 21.7 17.5 17.2 21 19.0 12.2 12.8 14.4 20.9 17.8 16.7 22 19.5 12.8 13.9 16.1 20.6 18.0 16.7 23 17.5 13.3 13.9 15.0 19.4 17.5 16.1 24 18.0 12.2 12.8 14.4 20.0 16.7 15.6 25 18.5 13.3 14.4 15.0 20.0 16.7 16.1 BB 1 14.5 12.2 12.2 15.0 17.2 17.2 17.2 2 14.0 11.7 12.2 15.0 16.7 16.9* 17.2 3 15.0 12.8 12.8 18.9 17.8 17.8 17.8 4 17.0 13.3 13.9 16.7 18.9 18.9 19.4 5 15.5 13.9 14.4 20.0 20.0 18.3 20.0 85 ------- Appendix C.10. Temperature (°C) of Substrate at 45-50 cm. Marsh Harvest Session 1 18.9 2 19.4 3 19.4 4 19.4 5 19.4 6 19.4 7 19.4 8 18.9 9 19.4 10 19.4 11 19.4 12 20.0 13 20.0 14 20.0 15 20,6 16 20.6 17 19.4 18 20.0 19 19.4 20 19.4 21 20.0 22 19.4 23 19.4 24 19.4 25 20.0 26 20.6 27 20.0 28 19.4 29 21.1 30 20.6 1 17.8 2 16.7 3 17.8 4 17.8 5 17.8 6 17.8 7 17.2 8 9 18.3 10 16.7 11 16.7 13.9 12.8 13.9. 13.3 13.9 12.8 13.9 12.8 15.0 12.8 14.7 12.8 14.7 12.8 14.7 12.8 14.7 12.8 14.7 12.8 14.7 12.2 15.0 12.8 15.0 12.8 15.6 13.9 15.3 12.8 15.3 13.3 15.0 12.8 15.6 13.9 13.9 12.8 13.9 12.8 14.4 12.8 14.4 12.8 13.9 13.3 14.4 12.8 14.4 13.3 15.6 13.9 13.9 13.3 14.4 13.3 15.6 13.9 15.0 13.9 13.9 12.2 13.0 11.7 14.4 12.8 13.9 12.2 13.9 12.2 14.4 12.2 13.9 12.2 14.4 11.7 13.3 11.7 13.9 12.8 13.9 12.8 13.9 16.7 15.0 17.2 14.4 17.2 14.4 17.8 11.4 17.8 13.9 17.2 14.4 17.8 14.4 18.3 14.4 17.8 15.0 18.3 14.4 17.2 15.0 18.3 14.4 17.2 16.1 18.9 16.7 23.3 15.0 18.3 15.0 17.2 15.6 17.8 13.3 15.0 13.3 15.0 15.0 17.2 14.4 16.7 15.0 17.8 15.0 17.8 13.9 17.2 15.6 18.3 15.6 17.8 14.4 17.2 16.7 18.3 15.6 19.4 13.9 18.3 13.9 17.0 15.0 17.5 13.9 16.7 13.3 16.1 13.3 16.1 13.9 17.2 13.9 16.7 13.9 16.7 13.9 17.0 14.4 18.1 17.2 17.8 18.3 18.9 16.7 17.8 18.3 18.9 17.2 18.3 16,1 17.2 17.8 18.9 18.3 18.3 18.3 18.9 18.9 18.9 18.3 18.3 18.9 19.4 17.8 17.8 18.9 18.9 22.2 20.6 18.3 18.3 18.3 18.3 17.8 18.3 15.6 17.2 15.6 17.2 16.7 17.2 16.7 17.8 18.3 18.9 17.2 18.3 17.8 17.8 18.3 20.0 17.8 18.3 17.8 18.3 18.9 20.0 18.9 19.4 16.9 17.2 16.9 16.7 17.5 16.7 16.7 15.6 15.6 15.6 15.6 15.6 17.2 16.1 17.0 16.7 17.0 16.7 16.9 16.7 17.2 17.2 continued 86 ------- Appendix C.10. cont. Marsh Harvest. Session 12 16.7 13.3 12.2 15.0 17.8 17.8 13 17.8 12.8 12.8 15.0 18.9 18.6 17.8 14 17.2 12.2 12.2 13.9 17.2 17.8 16.7 15 17.8 12.8 12.2 13.9 18.9 16.7 16.7 16 17.2 12.8 12.8 14.4 17.8 17.8 18.3 17 16.7 12.2 12.2 13.9 17.2 17.8 16.7 18 16.7 12.2 11.7 13.3 17.2 17.0 17.2 19 17.2 12.8 11.7 13.9 17.8 16.7 16.1 20 16.7 11.7 11.7 13.3 17.2 17.8 17.2 21 17.8 12.2 11.7 13.9 16.7 16.7 16.1 1 18.3 19.8 12.8 15.0 19.4 18.3 17.8 2 16.7 12.2 12.2 15.0 19.4 18.0 17.2 3 16.7 13.9 12.8 14.4 17.2 17.8 17.2 4 16.7 13.9 12.8 14.7 17.8 17.5 17.2 5 16.7 13.9 12.8 15.0 17.0 17.2 17.2 6 16.7 13.3 13.3 15.0 18.9 17.8 16.7 7 18.3 12.8 12.2 15.6 20.6 19.7 18.9 8 16.7 12.2 12.2 15.0 18.3 17.8 17.2 9 17.8 13.3 12.8 15.0 17.8 18.0 18.3 10 16.1 12.8 12.2 13.9 17.2 16.4 16.1 IT 16.1 12.8 12.2 13.9 17.2 16.4 16.1 12 16.7 13.3 12.8 14.4 18.3 16.9 16.7 13 16.7 13.9 13.3 15.3 18.3 17.8 17.2 14 17.8. 13.9 13.3 15.6 18.9 18.3 18.3 15 17.8 13.9 13.3 16.1 20.0 19.2 18.3 16 17.8 13.9 12.8 16.1 20.0 19.2 18.9 17 17.8 13.9 13.3 16.7 19.4 19.7 18.3 18 17.2 13.3 13.9 15.0 17.2 17.2 17.2 19 17.8 13.3 12.8 15.6 18.9 18.9 18.3 20 17.8 13.9 13.9 15.6 18.9 17.5 17.2 21 17.9 13.3 13.3 15.0 18.3 17.8 17.2 22 16.7 13.9 13.9 15.6 18.3 17.8 17.2 23 16.7 14.4 13.9 15.0 17.8 17.2 16.7 24 16.7 14.4 13.3 13.9 17.2 16.9 16.7 25 16.7 14.4 13.9 15.0 17.8 16.9 16.7 1 14.4 12.8 12.2 14.4 17.2 17.2 17.2 2 14.4; 12.8 12.8 14.4 17.2 16.7 16.7 3 15.6 13.9 13.3 15.0 17.2 17.2 17.2 4 16.7 14.4 13.9 15.6 18.9 18.0 18.9 5 17.8 14.4 15.0 16.1 18.9 18.3 18.9 87 ------- Appendix; D. Macroplot Elevation and Habitat Type. Habitat as Follows: Fore- Levee Slope (1), Levee Crest (2), Back Levee SI0De C3"). Back Levee Depression (4), Slope Below- Upl-and (5-).,. Up-Vand Transition (6), Pan (7). Marsh SRE LPL ETevati on Habitat Marsh Elevation Habitat 1 . 34a 6- LPL 12 .51 6 2 .15 4 13 .21 1 3 .35 2 14 .29 3 4 .42 2 15 .27 2 5 .08 2 16 .15 4 6 .33 2 17 .17 4 7 .22 4 .8 .31 2 8 .39 3 19 .33 2 9 .34 3 20 .25 3 10 .38 3 21 .25 3 11 .37 3 12 .35 3 UNB 1 1.05 6 13 .49 2 2 .84 5 14 -.30 1 3 .69 5. 15 .52 7 4 .44 ¦T 16 .13. 4 5 .40 1 17 .33 2 6 .27 1 18 -.27 1 7 1.17 6 19: .61 6 8 .77 5 20 .27 5 9 .51 3 21 .33 5 10 .47 3 22 .41 5. 11 .49 3 23 .20 4 12 .55 2 24 .24 4 13 .18 1 25 .18 4 14 .70 4 26 .15 4 15 .70 4 27 .11 3 16 .70 4 28 .14 3 17 .62 4 29 .14 4 18 .65 4 30 .11 3 19 .59 4 31 -.17 ¦1 20 .33 1 21 .56 4 1 .17 3 22 .54 3 2 .19 3 23 .31 3 3 .08 3 24 .53 2 4 .17 3 25 .22 1 5 .22 3 6 .28 3 BB 1 -.57 6 7 .25 2 2 -.87 5 8 .59 6 3 -.96 5 9 .57 6 4 -1.07 1 10 .24 6 5 -1.12 1 11 .24 2 aMeters; reference is local MHW. 88 ------- |