, Volume 170, Issue 3, pp 777–787 | Cite as

Geographic variation in salt marsh structure and function

Community ecology - Original research


We examined geographic variation in the structure and function of salt marsh communities along the Atlantic and Gulf coasts of the United States. Focusing on the arthropod community in the dominant salt marsh plant Spartina alterniflora, we tested two hypotheses: first, that marsh community structure varies geographically, and second, that two aspects of marsh function (response to eutrophication and addition of dead plant material) also vary geographically. We worked at eleven sites on the Gulf Coast and eleven sites on the Atlantic Coast, dividing each coast up into two geographic areas. Abiotic conditions (tidal range, soil organic content, and water content, but not soil salinity), plant variables (Spartina nitrogen content, height, cover of dead plant material, but not live Spartina percent cover or light interception), and arthropod variables (proportional abundances of predators, sucking herbivores, stem-boring herbivores, parasitoids, and detritivores, but not total arthropod numbers) varied among the four geographic regions. Latitude and mean tidal range explained much of this geographic variation. Nutrient enrichment increased all arthropod functional groups in the community, consistent with previous experimental results, and had similar effects in all geographic regions, contrary to our hypothesis, suggesting widespread consistency in this aspect of ecosystem function. The addition of dead plant material had surprisingly little effect on the arthropod community. Our results caution against the uncritical extrapolation of work done in one geographic region to another, but indicate that some aspects of marsh function may operate in similar ways in different geographic regions, despite spatial variation in community structure.


Fertilize Latitude Spartina Tide range Wrack 



We thank T. Decker, B. DeLong, C. Gratton, C. Grimm, H. Guo, C-K. Ho, L. Marczak, J. Martinez, M. Richardson, A. Stark, K. Wieski, G. Wimp, and H. Vu for help in the field and laboratory, and K. Wieski for help with the SEM analysis. We thank B. Cole, A. Frankino, and E. Siemann as well as two anonymous reviewers for advice and comments on the manuscript. We are grateful to the sponsors and staff of the 22 field sites where we worked for facilitating access and welcoming our activities. We thank the National Science Foundation (DEB-0638796, OCE-1045221, OCE-0620959) for financial support. This is contribution number 1015 from the University of Georgia Marine Institute. This work is a contribution of the Georgia Coastal Ecosystems Long-Term Ecological Research program.

Supplementary material

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Supplementary material 1 (DOCX 582 kb)


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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  1. 1.Department of Biology and BiochemistryUniversity of HoustonHoustonUSA

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