Infuence of land use practices on dominant tree species diversity, richness, evenness, and abundance in Ugenya Sub-county, Kenya

Abstract

Change in Land use practices are important indicators of socio-cultural and economic advancement. The common practices for example, rapid human settlement development and unsustainable livestock farming affect distribution of the dominant trees, conversely, Influence of the change in practices on the tree species diversity Richness, Evenness, and abundance is understood. Farm-forestry is contributing to the restoration of trees. However, information relating the 10% Farm-forestry and tree species diversity Richness, Evenness, and abundance is contradicting. Palatable tree organs are unsustainably harvested for forage supplement. Even so, proof about the Influence of stocking rate on the tree species diversity Richness, Evenness, and abundance was attracting varied qualitative justifications in the literature. Therefore, the aim of the study was to assess the Influence of land use practices on dominant tree species diversity, Richness, Evenness, and abundance. The specific objectives of this research were; to analyze Influence of human settlement on the species diversity, Richness, Evenness, and abundance to evaluate the Influence of farm-forestry on the species diversity, Richness, Evenness, and abundance and; to assess the Influence of livestock farming on the species diversity, Richness, Evenness, and abundance. Out of 33,565 households, using Fisher‟s formula, a sample size of 384 household heads was recruited for questionnaire administration between December 18th 2021 and February 24th of 2022. Descriptive cross-sectional survey design and Systematic random sampling was used. Primary data sources included; questionnaires, Focused Group Discussions, key informants, observation, measurement, and photography. Secondary data was extracted from; Geographical text books, publications, and print media. The Tree species that had a Diameter at Breast Height of ≥ 5.0 inches were enumerated and their diversity, richness, evenness, and abundance measured using Shannon Wiener‟s Diversity index. Palatability tests were performed, and tree forage preference measured using Manly‟s alpha/Chesson‟s index. Qualitative data on specific objectives which had mean scores were compared using the Independent Two-sample t test. The written and verbal information were categorized and analyzed theme wise. The Hubbert‟s Bubble pattern of depletion theoretical model was used. Quantitative data was processed by Microsoft Excel and analyzed using the R Statistics version 4.1.3. The null hypothesis was rejected, the multiple Coefficient of Determination (R2) showed that 67.6%, 57.2%, 48.4%, and 45.6% of the variations in the species Diversity, Richness, Evenness, and Abundance respectively could significantly be explained by the joint variation in the values of independent variables. The result revealed an average Shannon Wiener‟s diversity index (H) of M = 1.58, SD = 0.24 compared to a possible maximum of H = 4.5. A significant estimate of 52% of the sampled Dominant trees were established through planting. From the 27 tree species studied, an average richness (M= 6.00, SD = 2.41) and an abundance of (M = 36, SD = 2.46) per acre was reported. At approximately 13% Eucalyptus SPP was the highest ranked followed by Markhamia lutea at nearly 12%. A significant round figure of 59% of the species richness was composed of the indigenous trees. Species evenness was (M = .71, SD = 0.04), however, the enumerated 2510 trees with an average age of (M = 9.22, SD = 4.42) years, and DBH of (M = 6.83, SD = 1.99), the exotic trees registered a higher abundance of about 56%. It was therefore concluded that the studied Land Use Practices significantly influenced the dominant tree species diversity, richness, evenness, and abundance. To mitigate the low tree species diversity, richness, evenness, and abundance, it is crucial to sensitize the stakeholders on the ecological functions and benefits of diversifying the tree species establishments.