Thursday, August 10, 8:00-11:30 am
COS 88 - Estuarine and wetland ecology
L-14, Lobby Level, Cook Convention Center
Presiders: D Kashian and HN Morzaria Luna

Distribution of a parasitic plant in a California salt marsh.

Griffith, Katie*,1, 1 University of California, Santa Cruz, CA

ABSTRACT- A continuing challenge in ecology is to understand what determines the distributions of organisms. The intertidal zone is a very tractable system for examining the factors that control distributions. Most emphasis has been on dominant species that often occur in bands, with the key physical driver being tidal elevation. Fewer studies have attempted to explain the determinants of irregular or patchy distributions. Cuscuta salina (salt marsh dodder) not only exhibits a patchy distribution, but is an obligate parasite which adds another layer of complexity to the mechanisms generating its pattern of distribution. My work aims to characterize how the host plant (Salicornia virginica) may translate abiotic forces into a substrate for parasite growth. Because S. virginica is distributed in broad bands, it must be patchy in quality, resistance, or accessibility. I have documented the distribution of C. salina in relation to abiotic and biotic factors at Elkhorn Slough National Estuarine Research Reserve (in Central California). My results show patterns of distribution at three spatial scales. The probability of a C. salina infection increases 1) with increasing distance from the mouth of Elkhorn Slough; 2) with increasing distance from a tidal creek edge; and 3) where host tissue salinities fall below 70 ppt. Seed recruitment surveys (seed traps and wrack collection) suggest that C. salina seeds do not settle along the shoreline border of a marsh (or tidal creek edge) but are present in wrack deposits at higher elevations.

Key words: salt marsh, distribution, parasitic plants

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