Ecosystem Functions in East African Forest and Agro-Environments Depend on Site-Specific Microhabitat Conditions

Natural and seminatural habitats provide important resources for many plant and animal species. The destruction of such habitats might reduce biodiversity and disturb ecosystem functions. Sub-Saharan Africa suffers particularly under the destruction and deterioration of ecosystems due to demographic pressure. In this study, we analyzed ecosystem functions in a small remnant of East African coastal forest and the surrounding anthropogenic landscape. We measured pollination activity, predation, and seed dispersal. For each study plot, we also recorded local habitat conditions, which may also influence ecosystem functions. We found no significant difference between the natural forest and anthropogenic agro-environments for seed dispersal nor pollination. Insect predation showed highest rates inside the forest and decreasing rates in the open agro-environments. Local environmental conditions strongly affected ecosystem functions. For example, flower availability showed positive effects on pollination activity, and the availability of herbs on the ground positively influenced the level of predation. Rather homogenous ecosystems such as eucalyptus plantations and arable land showed lowest levels of ecosystem functions. Here, planting of undergrowth such as herbs and flowers may improve ecosystem functions. Our findings underline that natural forest as well as heterogeneous agro-environments provide a large variety of ecosystem functions, which strongly depend on site-specific microhabitat conditions.