Determining the influence of gap size on three selected microsite conditions in Southwestern Mau Forest reserve, Kenya

Southwestern (SW) Mau is experiencing anthropogenic and natural disturbances; creating canopy gaps influencing microclimate in the forest. This study determined the influence of canopy gap size on three microsite conditions (soil temperature, soil moisture and light intensity) in SW. The study utilized Ecological Survey Research Design; plots of 500 m by 500 m were laid in disturbed and undisturbed sites of Itare, Maramara and Ndoinet blocks. In the sampled gaps within the plots in disturbed sites; soil moisture and temperature were measured using Kensizer soil tester (3-in-1 moisture/light/pH). Light intensity was measured using the Luxmeter (model HTC LX-104). In undisturbed sites, 500 m by 500 m plots were laid and 30 m by 20 m quadrats randomly nested 19 times within. Four measurements were taken for every Microsite condition per sub-plot. Data was analysed using R and Microsoft excel. Descriptive statistics were given and Kruskal-Wallis test employed to determine differences in microsite conditions among the gap sizes. Wilcoxon rank sum test was used to compare microsite conditions between disturbed and undisturbed sites. The study revealed that there was significant difference in soil temperature (Kruskal-Wallis chi-squared=19.00, df=3, p-value=0.0002732) in the gaps. Additionally, there was significant difference in light intensity between disturbed and undisturbed sites (W=555, p-value=0.01). Non-significant results of some microsite conditions were attributed to Piper capensis and Ribes spp. which invaded medium and large canopy openings. It was concluded that canopy cover influences microsite conditions in forests. Gaps should be allowed to occur naturally for biodiversity conservation.