Effects of plants diversity on soil bacteria load in a tropical moist forest of Otuoke, Nigeria

Abstract

Most attempts towards forest management are directed towards management of forest resources which does not embrace other players. Key players in forest ecosystem are bacteria and fungi. Relationships between forests stand density and diversity with soil microbial population is an area of research that could aid in forest ecosystem management, this study was undertaken to provide the needed information. Three locations A, B, C of plot size 100 m x 100 m were purposefully selected. Site A and B were selected based on species richness and heterogeneity, while C was based on dominance and homogeneity. These were further divided into 25 m x 25 m subplots, and finally divided into 2 m x 2 m sample plots for investigation. Three of these were randomly selected from each site for identification and listing. Soil samples were collected across sites, inoculated, cultured and analyzed in the laboratory to estimate microbial population and identify microbial genera's. Species diversity were calculated using Shannon (H'), Simpson (D) and Sorensen's Coefficient (CC) indices. Bacteria and their colony forming units were calculated for sites. Results shows mean values of plant species diversity and mean values of bacteria counts were significantly (p < 0.05) different across the locations. Location A has a mean value 4.781 +/- 0.00 for Simpson Index, with mean bacteria load of 2.11 +/- 0.012 and 1.5115 +/- 0.00 for Shannon Index with very high level of diversity. Location B has moderate level of diversity with mean index of 3.675 +/- 0.00 for Simpson, and 1.375 +/- 0.00 for Shannon Indices, with mean bacteria load 2.40 +/- 0.21. Similarity content for locations A and B was 0.444. Plants diversity and bacteria load were positively significantly (p < 0.05) correlated with r2 of 76%. Increasing plants diversity will increase soil bacteria load. This would aid decisions making in forest conservation and ecosystem management.