A structural equation model of plant species richness and its application to a coastal wetland

American Naturalist
By:  and 



Studies of plant species richness have often emphasized the role of either community biomass (as an indicator of density effects) or abiotic factors. In this article we present a general model that simultaneously examines the relative importance of abiotic and density effects. General and specific models were developed to examine the importance of abiotic conditions, disturbance, and community biomass on plant species richness. Models were evaluated using structural equation modeling based on data from 190 plots across a coastal marsh landscape. The accepted model was found to explain 45% of the observed variation in richness, 75% of biomass, and 65% of light penetration. Model results indicate that abiotic conditions have both direct effects on the species pool and indirect effects on richness mediated through effects on biomass and shading. Effects of disturbance were found to be indirect via biomass. Strong density effects on richness were indicated by the results, and canopy light penetration was found to be a better predictor of richness than was biomass. Overall, it appears that richness in this coastal landscape is controlled in roughly equal proportions by abiotic influences on the species pool and density effects, with disturbance playing a lesser role. The structure of the general model presented should be applicable to a wide variety of herbaceous plant communities.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title A structural equation model of plant species richness and its application to a coastal wetland
Series title American Naturalist
DOI 10.1086/285999
Volume 149
Issue 3
Year Published 1997
Language English
Publisher University of Chicago Press
Contributing office(s) National Wetlands Research Center
Description 25 p.
First page 436
Last page 460
Country United States
State Louisiana, Mississippi
Other Geospatial Pearl River Basin
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