Theme 1: Rangeland/Grassland Ecology--Oral Sessions

Description

Information on the state of woody vegetation of Rusinga Island is urgently needed in order to develop appropriate and effective conservation guidelines. Rusinga Island is an ancient historic area with numerous archeological sites and a bountiful of birdlife. However, the Island is characterized by highly degraded ecosystems from human disturbances such as cutting down of trees for fuel, construction poles, and overgrazing resulting in a remarkable degradation of flora, alteration of the ecosystems and loss of biodiversity. This study sought to determine the composition and diversity of woody plant species in Rusinga Island to understand the current status in order to develop appropriate and effective conservation measures since no such study has been conducted in the area before. Three hills (Ligongo, Agiro and Wanyama) were selected for sampling and demarcated into three study zones differentiated by the slope gradient and land use. A systematic random sampling approach was adopted to establish 98 sampling plots measuring 20 m x20 m (400m2) for recording tree species and subplots of 10 m by 10 m within the main plots for recording shrubs and lianas across the three study zones at an interval of 200m. A total of 63 woody plant species belonging to 32 families and 51 genera were recorded, out of which 66.7% were trees, 31.7% shrubs and 1.6% lianas. The upper zones had significantly higher species diversity, species richness, evenness and abundance compared to the middle and lower zones. The lower zones depicted a lower abundance of plants and least similarities of species compared to the middle and upper zones. Development of appropriate conservation and management strategies is required in order to protect the woody plant resources from unsustainable human activities and to improve the natural diversity of the Island.

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Woody Plant Species Composition and Diversity in Rusinga Island, Homa Bay County, Kenya

Information on the state of woody vegetation of Rusinga Island is urgently needed in order to develop appropriate and effective conservation guidelines. Rusinga Island is an ancient historic area with numerous archeological sites and a bountiful of birdlife. However, the Island is characterized by highly degraded ecosystems from human disturbances such as cutting down of trees for fuel, construction poles, and overgrazing resulting in a remarkable degradation of flora, alteration of the ecosystems and loss of biodiversity. This study sought to determine the composition and diversity of woody plant species in Rusinga Island to understand the current status in order to develop appropriate and effective conservation measures since no such study has been conducted in the area before. Three hills (Ligongo, Agiro and Wanyama) were selected for sampling and demarcated into three study zones differentiated by the slope gradient and land use. A systematic random sampling approach was adopted to establish 98 sampling plots measuring 20 m x20 m (400m2) for recording tree species and subplots of 10 m by 10 m within the main plots for recording shrubs and lianas across the three study zones at an interval of 200m. A total of 63 woody plant species belonging to 32 families and 51 genera were recorded, out of which 66.7% were trees, 31.7% shrubs and 1.6% lianas. The upper zones had significantly higher species diversity, species richness, evenness and abundance compared to the middle and lower zones. The lower zones depicted a lower abundance of plants and least similarities of species compared to the middle and upper zones. Development of appropriate conservation and management strategies is required in order to protect the woody plant resources from unsustainable human activities and to improve the natural diversity of the Island.