Ecological zones in the Southern Appalachians: first approximation

  • Authors: Simon, Steven A.; Collins, Thomas K.; Kauffman, Gary L.; McNab, W. Henry; Ulrey, Christopher J.
  • Publication Year: 2005
  • Publication Series: Research Paper (RP)
  • Source: Res. Pap. SRS-41. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 41 p.


Forest environments of the Southern Appalachian Mountains and their characteristic plant communities are among the most varied in the Eastern United States. Considerable data are available on the distribution of plant communities relative to temperature and moisture regimes, but not much information on fertility as an environmental influence has been published; nor has anyone presented a map of the major, broad-scale ecosystems of the region, which could be used for planning and management of biological resources on forestlands. Our objectives were to identify predominant ecological units, develop a grouping of geologic formations related to site fertility, and model and map ecological zones of the Southern Appalachians. We synthesized 11 ecological units from an earlier analysis and classification of vegetation, which used an extensive database of over 2,000 permanent, 0.10-ha, intensively sampled plots. Eight lithologic groups were identified by rock mineral composition that upon weathering would result in soils of low or high availability of base cations. The presence or absence of ecological zones (large areas of similar environmental conditions consisting of temperature, moisture, and fertility, which are manifested by characteristic vegetative communities) were modeled as multivariate logistic functions of climatic, topographic, and geologic variables. Accuracy of ecozone models ranged from 69- to 95-percent correct classification of sample plots; accuracy of most models was > 80 percent. The most important model variables were elevation, precipitation amount, and lithologic group. A regional map of ecological zones was developed by using a geographic information system to apply the models to a 30-m digital elevation dataset. Overall map accuracy was refined by adjusting the best probability cut levels of the logistic models based on expert knowledge and familiarity of the authors with known ecological zone boundaries throughout the study area. Preliminary field validation of an uncommon fertility-dependent ecological zone (Rich Cove) indicated a moderate, but acceptable level of accuracy. Results of this project suggest that bedrock geology is an important factor affecting the distribution of vegetation. The developed map is a realistic depiction of ecological zones that can be used by resource managers for purposes ranging from broad-scale assessment to local-scale project planning.

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  • Citation: Simon, Steven A.; Collins, Thomas K.; Kauffman, Gary L.; McNab, W. Henry; Ulrey, Christopher J. 2005. Ecological zones in the Southern Appalachians: first approximation. Res. Pap. SRS-41. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 41 p.
  • Keywords: Classification, ecosystems, fertility, geologic formations, logistic regression, moisture, multivariate analysis, ordination, temperature
  • Posted Date: March 22, 2006
  • Modified Date: August 22, 2006
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