Vegetation Ecology and Plant Diversity of Hugumburda-Gratkhassu National Forest Priority Area, Northeastern Ethiopia: Habitat Fragmentation in Time and Space
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Date
2015-11
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Addis Ababa Universty
Abstract
This study was conducted with the objectives of analyzing and understanding the species
composition, diversity, structure and regeneration dynamics of Hugumburda-Gratkhassu
NFPA in relation to land use\land cover and habitat fragmentation. A total of 77
quadrats were sampled using stratified sampling with optimum allocation method. In the
quadrats, data on abundance, height and DBH of woody plant species as well as
landscape variables were recorded. Within the main quadrat, five 2 m x 2 m subplots
were laid to collect data on seedlings, saplings and herbaceous species. In addition, in
each subplot, soil samples were collected and soil texture, electrical conductivity and pH
were analyzed. In order to investigate edge effect, 17 forest patches were selected and
sampling points for vegetation and environmental variables were established at 0, 50,
100, 150 and 200 m from the edge. A total of 83 quadrats were selected for this study.
Furthermore, Satellite images were acquired and analyzed by using remote sensing
technology and GIS mapping to generate information on the temporal and spatial
changes in land use\land cover types and habitat fragmentation. A total of 326 plant
species representing 238 genera and 88 families were recorded; shrub and herb species
are dominant. Cluster analysis resulted in five different plant communities and this result
was supported by the ordination result. CCA result showed altitude was the main
environmental variable in determining the plant communities. Species richness, diversity
and evenness varied among the plant communities and along the edge gradient. Analysis of population structure and regeneration status of the two Forest remnants revealed
various patterns and generally dominated by small sized individuals. In addition, the
results of image analysis revealed that disturbance was the major driving force for
fragmentation and patchiness of the remnant natural vegetation and thus exposing plant
species to various environmental effects at edge habitats. Consequently, the forest edge
habitats were found to possess lower species richness, diversity, tree density and basal
area compared to the inner habitats. Therefore, to adequately conserve and ensure
species survival and maintain species diversity in the study area, these forest remnants
and edge habitats should be maintained and well managed.
Key words/phrases: dry afro-montane forest, edge effect, Hugumburda-Gratkhassu,
habitat fragmentation, land use\land cover, plant community, National Forest Priority
Area, species richness, vegetation ecology
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Keywords
Dry afro-montane forest, Edge effect, Hugumburda-Gratkhassu, Habitat fragmentation, land use\land cover, Plant community, National Forest Priority Area, Species richness, Vegetation ecology