Abstract
Previous studies have shown that variations in environmental conditions play a major role in explaining variations in plant species richness at community and landscape scales. In this study, we considered the degree to which fine-scale spatial variations in richness could be related to fine-scale variations in abiotic and biotic factors. To examine spatial variation in richness, grids of 1 m2 plots were laid out at five sites within a coastal riverine wetland landscape. At each site, a 5 × 7 array of plots was established adjacent to the river's edge with plots one meter apart. In addition to the estimation of species richness, environmental measurements included sediment salinity, plot microelevation, percent of plot recently disturbed, and estimated community biomass. Our analysis strategy was to combine the use of structural equation modeling (path modeling) with an assessment of spatial association. Mantel's tests revealed significant spatial autocorrelation in species richness at four of the five sites sampled, indicating that richness in a plot correlated with the richness of nearby plots. We subsequently considered the degree to which spatial autocorrelations in richness could be explained by spatial autocorrelations in environmental conditions. Once data were corrected for environmental correlations, spatial autocorrelation in residual species richness could not be detected at any site. Based on these results, we conclude that in this coastal wetland, there appears to be a fine-scale mapping of diversity to microgradients in environmental conditions.
Original language | English (US) |
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Pages (from-to) | 39-50 |
Number of pages | 12 |
Journal | Plant Ecology |
Volume | 178 |
Issue number | 1 |
DOIs | |
State | Published - Mar 2005 |
Bibliographical note
Funding Information:This paper was prepared as part of a graduate seminar course associated with the Knowledge Network for Biocomplexity (KNB) at the National Center for Ecological Analysis and Synthesis. Partial support was provided by National Science Foundation Grant # DEB99-80154. We wish to thank Mike Willig, Bob Waide, Sandy Andelman, and Eric Fegraus for assistance with the KNB course. Thanks to Prof E. Berg-meier, Tammy Charron, and two anonymous reviewers for help refining the manuscript.
Keywords
- Autocorrelation
- Coastal wetland
- Louisiana
- Path modeling
- Spatial scale
- Species richness
- Structural equation modeling