EDGE EFFECTS AT AN INDUCED FOREST-GRASSLAND BOUNDARY - FOREST BIRDS IN THE ONGOYE FOREST RESERVE, KWAZULU-NATAL

Bird species diversity and guild composition between the edge (5-10 m from the margin) of primary forest abutting grassland and the deep int erior(> 500 m from the margin) in the Ongoye Forest Reserve were compa red. Edge and interior sites were chosen that were homogeneous with re spect to habitat physiognomy i.e. influences of habitat structure and complexity were insignificant. There were no statistical differences i n bird species diversity between the forest edge and interior. However , there was significantly greater species turnover at the edge. The di fference in bird species composition between the forest edge and inter ior was due to various edge-effects: removal of dead wood for firewood , soil compaction by cattle, and generally greater levels of disturban ce. We question the wisdom of the generally applied edge-effect princi ple in the conservation of forest biodiversity. We suggest that the pr inciple be applied only once there has been critical appraisal of the extent, nature, and effect of an edge and a clear conservation objecti ve with regard to forest birds.