Assessment Of Human Impacts On Woody Plant Diversity In Yayu Biosphere Reserve, Southwestern Ethiopia

Abstract

Yayu Biosphere Reserve (YBR) is part of the Eastern Afromontane Biodiversity hotspot located in Illu Abbabor Zone, Oromia, Ethiopia. Understanding the patterns and intensity of anthropogenic impacts on habitats is important in the conservation of the Biosphere Reserve. However, the impacts of human disturbance on woody plant diversity and their relative severity was not well known. Hence, this study aimed to examines the impact of human disturbance on woody plant diversity in case of Yayu Biosphere Reserve, Oromia National Regional State South-western Ethiopia. Yayu district was purposively selected based on its forest potential, three representative Kebele were randomly selected, and households sample were selected by using the systematic random sampling techniques. A total of nine forest patches were designated to collect vegetation data. Three patches were designated as per zonations of Yayu Biosphere Reserve (core zone, buffer zone and transition zone). In each forest patches, five-line transects of 1km long were randomly placed parallel to each other. From those of the five-line transects, one line transect was randomly selected. A total of 28 quadrats were taken to assess vegetation diversity by measuring 20m × 20m, 5m×5m and 3m×3m for matured trees, sapling & seedling, respectively. A total of 145 representative households were selected to collect social survey data. One way ANOVA were used to analysis Quantitative data, and chisquare for social data analysis. The present findings pointed out that the main threats to the existing remnant forest patches in Yayu Biosphere Reserve were an anthropogenic disturbance; extraction of timber, fuel-wood Collection, forest land for agriculture; sandy soil extraction, livestock grazing, forest land for coffee plantation, and fire damage. There was high human interference in core zone of the Yayu Biosphere Reserve. This indicated that there is a modification of natural forest into coffee plantation by local community in study area. Medium and high human disturbance classes were characterized by low species diversity, and poor regeneration status whereas, very low and low human disturbance plots were characterized by high species diversity, and good regeneration status. Species richness and species abundance were significantly different among the all human disturbance classes and all Zonation of the Biosphere Reserve (P<0.05). The local community perception on forest conservation strategies indicated that 42.8% of the respondents perceived conservation management was done by the residents whereas, 28.9% was conserved with a collaboration of all stakeholders. Hence, this study has provided the first useful ecological information on the main human disturbance activities, effects of human disturbance on woody species diversity and community perception in the Yayu Biosphere Reserve that would serve as an input for management decisions. Therefore, special attention should be needed by all stakeholder to embrace participatory management by encouraging and supporting the formation of community forest association.