The effect of forest gap size and age on plant species diversity in Budongo forest

Abstract

Tropical rain forests are noted for their extraordinary species diversity. They are the most diverse and structurally complex ecosystems in the world. Gap dynamics and forest regeneration in tropical rainforests has been widely studied by many scientists and ecologists, with applications in sustainable forest management. The presence of forest gaps in Budongo provides an opportunity to understand the process of forest regeneration. Fifteen (15) Line transects were established in Budongo forest, the forest gaps along the transects were sampled. Gap size, shape and age were determined, closed canopy plots of equal area were set up near the gap. The tree species within the gaps and closed canopy areas were identified and recorded. 30 gaps and 30 plots of varying sizes as determined on site were sampled for this study so as to compare the species diversity in forest gaps and closed canopy areas. Fifty-two (52) tree species were recorded during this study. Forty-seven (47) tree species were recorded in the thirty (30) forest gaps sampled whereas forty-six (46) tree species were recorded in the thirty (30) closed forest plots. The most frequent gap marker was maesopsis eminii. Findings from this study showed that gap shape influenced species diversity, gap size had a positively correlation with species diversity while gap age had no effect on species diversity. Forest gasp and closed canopy areas had similar species richness. These findings therefore show that forest gap size plays a crucial role in promoting and maintaining the high tree species diversity in Budongo Forest. This study therefore recommends that forest managers should optimize the number of trees harvested to between two to three because majority of treefall gaps in Budongo were formed by two gap markers. The study also recommends that forest managers should ensure that the shape of the site from which tree are harvested should be Oval or Rectangular not exceeding 500m² in area because these gap shapes had high species diversity. Tree species such as Maesopsis eminii that were found to be frequent gap markers should be the main species harvested from the forest.