| dc.description |
Ecoregions are regions of relative homogeneity with respect to specific
ecosystem variables (Bailey 1976; Omernik 1995). There has been an increasing
awareness that effective management of environmental resources must be undertaken
with an ecosystem perspective (Omernik, 1995). Ecoregions serve as a spatial
framework for assessing, managing, and monitoring ecosystems that have gained
recognition among scientists and resource managers as a more effective boundary for
natural resource assessment and management compared to the more arbitrary nature of
political boundaries (Bryce et al, 1999). Each region can be viewed as a discrete system that is representative of the interaction between geology, landforms, soils, vegetation, climatic, hydrological, and human variables (Omernik 1995). Ecoregion maps are
primarily produced by qualitative analyses for boundary delineations, which are often
derived by consensus with indistinct weighting of input variables, and are essentially impossible to replicate by others. This paper presents the process and results of using multiple spatial analysis techniques within a geographic information system (GIS) as a potentially more quantitative and transparent tool for delineating ecoregions. Due to the qualitative nature of prior EPA ecoregion delineations and in an effort to quantify
accuracy, this research focused on emulating the existing large-scale ecoregions nested
within the Oregon portion of the EPA’s Klamath Mountain Ecoregion straddling
southern Oregon and northern California. Results indicate that replicating qualitative
(EPA) ecoregions with a more quantitative process such as those within a GIS has
potential but is currently problematic, with accuracy that is low (~37%) when compared
to the original delineations. Increases in GIS data quantity, accuracy, resolution, and
attribute richness will improve quantitative modeling potential. Additionally,
quantitative EPA Level IV ecoregion replication that is highly similar to existing ecoregions will require extensive collaboration between researchers and the original manual delineation geographers with particular attention focused on delineation
processes in areas with broad ecotones. |
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