Abstract
Heavy rainfall in 1978 and 1980 caused flooding of southern California salt marshes. Examination of three marshes demonstrated a broad range of freshwater effects which correlated with the degree of change in soil salinity. At Tijuana Estuary (1980), a short-term reduction in the salinity of normally hypersaline soils was followed by a 40% increase in the August biomass of Spartina foliosa. At Los Penasquitos Lagoon (1978), a longer period of brackish water influence was followed by a 160% increase in August biomass of Salicornia virginica. At the San Diego River (1980), flood flows were augmented by major reservoir discharge. Continuous freshwater flow leached most of the marsh soil salts and caused replacement of halophytes by freshwater marsh species. The first two cases probably fell within the normal range of flooding events, even though the hydrology of both watersheds has been modified. The vegetation response was functional; productivity increased but there was no major change in species composition. As expected, vegetation rapidly returned to preflood conditions. However, the long-term freshwater flow in the Dan Diego River was unnatural. Floral composition changed as soils were leached of salts. Recovery following the return of saline soils has been slow because many native halophytes are not good colonizers. The system's resilience is limited, and modification of natural stream discharge can cause permanent changes in coastal wetlands.
Similar content being viewed by others
Literature Cited
Connor, W. H., J. G. Gosselink, and R. T. Parrondo. 1981. Comparison of the vegetation of three Louisiana swamp sites with different flooding regimes. Am. J. Bot. 68:320–331.
Gallagher, J. L., and H. V. Kibby. 1981. The streamisde effect in a Carex lyngbyei estuarine marsh: the possible role of recoverable underground reserves. Est. Coast. Shelf Sci. 12:451–460.
Holling, C. S. 1973. Resilience and stability of ecological systems. Ann. Rev. Ecol. Syst. 4:1–23.
Mahall, B. E., and R. B. Park. 1976. The ecotone between Spartina foliosa Trin, and Salicornia virginica L. in salt marshes of northern San Francisco Bay. III. Soil aeration and tidal immersion. J. Ecol. 64:811–819.
Nordby, C. S., J. B. Zedler, P. Williams, and J. Boland. 1980. Coastal wetlands restoration and enhancement. Final report to U.S. Navy Wildlife and Natural Resources Office, Naval Air Station, North Island, San Diego, CA.
Onuf, C.P., M. L. Quammen, G. P. Shaffer, C. H. Peterson, J. W. Chapman, J. Cermak, and R. W., Holmes. 1978. An analysis of the values of central and southern California coastal wetlands. In P. E. Greeson, J. R. Clark, and J. E. Clark (eds.), Wetland functions and values: the state of our understanding. American Water Resources Assoc., Minneapolis, p. 186–199.
United States Geological Survey, 1975–1979. Water resources data for California. USGS, Menlo Park, CA.
Zedler, J. B. 1977. Salt marsh community structure in the Tijuana Estuary, California. Estuarine Coastal Mar. Sci. 5:39–53.
Zedler, J. B. 1980. Algal mat productivity: comparisons in a salt marsh. Estuaries 3:122–131.
Zedler, J. B. 1981a. Coastal wetlands management: Restoration and establishment. In California Sea Grant College Program 1978–1980 Biennial Report, UCSD, La Jolla, p. 56–60.
Zedler, J. B. 1981b. The San Diego River Marsh before and after the 1980 flood. Environment Southwest No. 495:20–22.
Zedler, J. B. 1982. The ecology of southern California coastal salt marshes: a community profile. U.S. Fish and Wildlife Service, Biological Services Program, Washington, D.C.: FWS/OBS-81/54. 110 p.
Zedler, J. B., R. Winfield, and P. Williams. 1980. Salt marsh productivity with natural and altered tidal circulation. Oecologia (Berl) 44:236–240.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Zedler, J.B. Freshwater impacts in normally hypersaline marshes. Estuaries 6, 346–355 (1983). https://doi.org/10.2307/1351393
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.2307/1351393