Date of Award
Program or Major
Doctor of Philosophy
Thomas D Lee
My objective was to design a conservation reserve system that included multiple viable examples of all ecological community types within one specific ecoregion---the Northern Appalachians. I developed and defined the boundaries of the ecoregion, constructed a comprehensive list of the ecological communities and determined their scale of occurrence and distribution patterns. I also assessed the types and distributions of biophysical features within the ecoregion and developed a hierarchical scheme to partition the region into biophysical subregions. Subsequently, I assessed 1500 occurrences of ecological communities in the region compiled from state Natural Heritage databases and an analysis of roadless areas. Each occurrence was required to meet viability criteria while replicate viable occurrences were identified across biophysical subregions to increase the overall chances of each community persisting over time. The viability criteria were designed to insure that each occurrence had the ability to absorb and recover from disturbances, contained associated fauna, and included intact landscape processes. Specific size and replication requirements were determined by the scale of the community in the ecoregion across three size classes: (1) matrix-forming (1,000--1,000,000 acres, continuous), (2) large patch (50--1,000 acres, semi-discrete) and (3) small patch (1--50 acres, discrete), and by the degree of endemism of the community to the ecoregion. In total, 510 community occurrences (34%) met the viability criteria. These were distributed across 120 community types with 38 occurrences being matrix-forming and 482 being patch communities. Collectively, the viable occurrences encompassed over 5 million acres (15% of the ecoregion). However the portfolio was short of its initial minimum goals by over 1100 occurrences including six 25,000-acre matrix occurrences across four subregions. Many of these apparent shortages may be artificial due to a lack of comprehensive knowledge of the patch communities that are contained within the selected matrix sites. The portfolio of occurrences identified in this study constitutes a detailed first approximation of the scope and locations of all the features necessary to protect biodiversity in the ecoregion.
Anderson, Mark Gustav, "Viability and spatial assessment of ecological communities in the northern Appalachian ecoregion" (1999). Doctoral Dissertations. 2102.