Assessing the influence of elephant damage on seedling colonization in Kibale Forest National Park.

Abstract

Vegetation damage attributable to elephants appears to be increasing and may result in the modification of afro-tropical forests. Recent studies have focused on the role of elephant damage in the depleting forest plant communities mainly mature tree species, saplings, shrubs, grasses and herbs from the ecosystem. However, less attention has been given to the damage on woody seedlings and its effects on the future of forest plant communities. Here, the influence of elephant damage on seedling colonization was assessed in Kibale National Park, Uganda. Specifically, seedling species composition, diversity were compared between elephant-damaged and undamaged and the influence of habitat characteristics on seedling diversity was tested. Seedlings were identified and counted in 10 sample plots (2m × 2m each) in elephant-damaged and undamaged sites in unlogged, logged and heavily-logged compartments. The habitat characteristics sampled in the plots were identity of nearby mature tree, distance to the nearby mature tree, canopy openness, grass cover, litter depth. Unconstrained ordination was used to obtain seedling species composition and generalized linear models were used to compare seedling diversity between elephant-damaged and undamaged sites. The study revealed no significant influence of elephant damage on seedling species composition. Seedling species abundance but not diversity significantly decreased in damaged sites as opposed to undamaged sites. Analysis of site characteristics including Distance to the nearby mature tree, Canopy Openness and Grass cover revealed an indirectly proportional relationship with seedling species abundance. Litter depth, on the other hand was directly proportional to seedling species abundance. Overall, site characteristics had no significant influence on seedling species diversity. In summary, elephant damage significantly reduced seedling species abundance and suppressed the regeneration of most seedling species. The results also demonstrates that site characteristics greatly facilitate seedling colonization considering seedling species composition did not vary greatly between the damaged and undamaged sites. This study calls for interventions to minimize elephant disturbances in the forest by focusing on species that can cope with damage for restoration activities and protecting endangered species that are desired by elephants so as to foster successful native species recruitment.