The Relationship between Soil Fertility and the Forests of the Southern Appalachian Region

Abstract

This study examines the distribution of plant communities across the Southern Appalachian region and seeks to understand the role that soil fertility plays in the complex pattern of vegetation that exists in this landscape. A regional dataset consisting of 1,273 sample plots was used to explore patterns of species composition. A total of 6 vegetation classes and 19 plant communities were classified from this dataset. The correlation of environmental variables with Nonmetric Multidimensional Scaling (NMDS) ordinations indicated three major environmental gradients, elevation (a surrogate for temperature ), topographic landform (a surrogate for moisture), and soil fertility (base cations). The regional dataset was subset to mesophytic plant communities (Acidic Cove Forests, Rich Cove Forests, and Mesic Montane Oak-Hickory Forests) that represent narrow segments of the elevation and topographic landform gradients. Variables associated with soil fertility were highly correlated with the NMDS ordination of this reduced dataset. Finally, Acidic Cove Forests and Rich Cove Forests were examined separately. Soil fertility variables continued to be important correlates with patterns of species composition within Acidic Cove Forests. The Rich Cove Forests also exhibited a strong relationship between soil fertility and species composition. In addition, much of the compositional variation in Rich Cove Forests appears to have a geographic component. Future efforts to understand the causal factors of species distribution in this region should consider soil fertility.