Ecosystem Viability Assessment and Fragmentation Analysis in Bale Mountains National Park (Emphasis on Afro-Alpine Ecosystem)
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Date
2010-06
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Addis Ababa Universty
Abstract
Human population growth is fragmenting pristine ecosystems and impacting biological
diversity worldwide. Like many National Parks forest fragmentation and degradation due
to agricultural expansion are the greatest threats to biodiversity in BMNP. However,
despite the presence of fragmentation, there are still opportunities for conserving the
remaining ecosystem blocks (Patches) with information on the viable and fragmented
Patches. Thus, the objective of this research is to suggest a ranking of ecosystem
patches according to their degree of viability (i.e. their capability to preserve its integrity
and host its original biodiversity). This study used Pearson correlation coupled with PCA
for objective selection of representative metrics among 109 and 72 at Class and patch
level, respectively. Pearson correlation (|r|>0.95) reduced 56% of the class and 14%
Patch metrics. Then PCA identified 6 and 7 components explaining 96% and 94% of the
variance in class and patch metrics, respectively. Accordingly, patch elongation, patch
size, core area, contiguity, proximity and Euclidean Nearest Neighbor were selected the
7 PCA components for ecosystem viability assessment. Weighted sum equations
combining representative metrics using percent of variance explained by each axes of
the PCA gave fragmentation Index and ecosystem viability map ranking classes and
patches as high, moderate and low, respectively. This systematic approach of creating
a fragmentation index and ecosystem viability assessment is not only a useful method
that can be replicated in other regions, but the information provided in the form of maps
can also be valuable guide to ecologists, natural resource managers, and planners to
orient land use planning for optimal allocation of land resources.
Keywords: Ecosystem fragmentation, Ecosystem Viability, PCA, Bale Mountains National Park.
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Keywords
Ecosystem fragmentation, Ecosystem Viability, PCA, Bale Mountains National Park