LAND USE CHANGES AND FLORAL DIVERSITY IN KENYA'S MT. ELGON FOREST ECOSYSTEM

Abstract

Background. Montane forests encompass spectacular landscapes, a wide variety of ecosystems, a great diversity of species, and distinctive human communities. Mountain forests support about one quarter of world's terrestrial biodiversity and include nearly half of the world's biodiversity "hotspots. Understanding of land use change (LUC) in mountain forest ecosystem is crucial for sustainable management of the ecosystem especially in developing countries like Kenya where the majority of the people depend on natural resources for their livelihoods. Changes in land use in this forest ecosystem could lead to a decline in biodiversity and in the livelihoods of the forest adjacent communities. Objective: To evaluate the differences in land use changes and floral diversity of Mt. Elgon forest ecosystem. Methodology: Differences in land use changes on floral diversity were evaluated using quadrats that were placed in different land uses to measure species diversity and abundance. The Shannon-Weiner diversity index and Whittaker beta diversity index was used to determine changes and similarities in floral diversity, while Kruskal-Wallis test and chi square test was used to determine differences in species abundances. Result: This study established that there were differences in floral diversity in relations to land use changes. The Shannon-Weiner diversity index revealed that control (natural forest) site had the highest species diversity (H=2.07331, evenness=0.884), followed by indigenous plantations (H=1.93962; evenness 0.69957), urban settlements (H=1.85081; evenness=0.66754), Nyayo Tea Zone (H=1.5324, evenness=0.56), mixed farming (H=1.43694, evenness=0.43694) and exotic plantation (H=1.28231, evenness=0.61612). Whittaker beta diversity index for control site verses urban settlements was (0.5385), indigenous plantations (0.2222), Nyayo Tea Zone (0.1429) while mixed farming and exotic plantations (0.000). Kruskal-Wallis test revealed a statistically significant differences in total number of plant species in the various study sites (H=8.288; P=0.049). Similarly, the results revealed a significant difference between specific plant communities (trees, shrubs, herbs, ferns, and climbers) in the study area (H=38.116; P=0.000). Chi square test of homogeneity was used to test difference in distribution of species communities in different location and the results revealed that the differences were insignificant. Implications: Results of species diversity analyses show differences in floral diversity and similarities in areas under different land uses. Conclusion: There are significant differences in floral diversity in areas under different land uses of Mt. Elgon forest ecosystem. Species diversity and similarity of indigenous planted forests and urban settlement closely approach that of the natural forests. Floral diversity play a critical role in provisioning of essential ecosystem services.