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Forest fragmentation and selective logging can influence the life cycle of tropical tree species at several levels, e.g., by lowering pollination, by limiting seed dispersal, and by increasing seed predation. Understanding human-induced modifications in ecosystem processes such as seed predation is essential for conservation management of threatened species. We studied the impact of forest fragmentation and selective logging on seed predation of the endangered tree Prunus africana in the tropical rain forest of Kakamega, Kenya. We quantified the activity of seed predators in the main forest, forest fragments, and in sites of different logging intensity in the dry and rainy seasons of 2003 and 2006. Further, we performed predation experiments with single and groups of P. africana seeds in the same sites. We recorded a tendency toward higher activity of seed predators in the main forest compared to fragmented sites. Single seeds, in contrast to groups of seeds, had marginally significantly higher predation rates in intensively logged compared to moderately logged sites. Overall, predation rates showed little relationship to seed predator activity and were highly variable among years and seasons. Additional studies on seedling establishment and survival are needed to predict whether the endangered tree is able to maintain sustainable populations in Kakamega Forest. Only by studying all processes in the life cycle is it possible to develop sound management strategies for the species. |
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