ANTHROPOGENIC INFLUENCES ON SPECIES COMPOSITION AND DIVERSITY DRYLAND FOREST FRAGMENTS KITUI EASTERN KENYA

Abstract

Increase in human population has devastating effects on many dryland forest fragments in Eastern Kenya. The objectives of this paper are to determine (i) key human activities in Kitui dryland forest fragments, (ii) tree species composition and (iii) impact of human activities on tree species composition and diversity. Two belt transect of 20 m wide and 500 m long that employed use of nested sample plots of

20 m ×20 m, sub-plots of 10 m ×10 m and micro- plots of 2 m ×5 m were established in each forest.

Human activities occurred in both forests but with high frequency (P<0.05) in Museve. Introduction of exotic species boosted species composition in Museve forest recording 68 species compared to Mutuluni with 57 species. However, it altered species dominances in Museve with Eucalyptus saligna (SIV = 16.77%), an exotic species being most dominant and reduced species similarity (JIA = 0.37) across the two forests. Tree cutting reduced (P<0.05) species richness and diversity in Museve which recorded lower Shannon Diversity Index (H’=1.46) compared to Mutuluni (H’=1.50). Thus, this study concludes that human activities affected species composition in both forests with Museve forest most disturbed. It thus recommends improved conservation measures for both forest reserves with most attention on Museve and further research on consequences of altering species dominance by Eucalyptus saligna in Museve forest.