The effectiveness of protected areas for common birds within a residential and agricultural landscape in South Africa
Protected Areas are landmarked as biodiversity conservation areas. However, despite their acceptance world-wide, their effect of conserving biodiversity is surprisingly poorly understood, and even target species within protected areas have been reported to decline. Here, we examine how protected areas are impacting 232 common bird species throughout a diverse landscape within South Africa. Common birds are good bio-indicators, hence our analyses allows us to make inferences about the general health of the ecosystem under study. We used an extension of newly developed occupancy models, abundance models, to determine the relative abundances of bird populations within and outside of protected areas in South Africa. This gives us an indication of how well protected areas are conserving bird species. We use data collected from the South African Bird Atlas Project 2 (SABAP2; 2007-ongoing).
We found that protected areas did not have a homogeneous affect for all birds considered here. Of the 232 species, 76 (33%) were statistically more abundant in reserves, 43 (19%) were less abundant, and the remaining 113 (48%) were neither more nor less abundant within reserves. We examined variation in abundance as a function of feeding guilds and identified three main clusters. Cluster 1 consisted of predators and frugivores who were very much more abundant in protected areas than outside; cluster 2 consisted of insectivore and vegivores who were more abundant inside than outside; and cluster three consisted of only granivores who were less abundant within reserves. These results can be partially attributed to the proximity of the protected area to different landscapes, such as cities, and farming areas, which may suit the needs of specific feeding guilds. This illustrates that protected areas in this particular area of South Africa protect certain types of birds, and that protection is uneven over all bird species. Additionally, landscapes other than Protected Areas, such as cities and farmlands, provide an essential role in bird conservation in South Africa, and our results suggest that schemes which encourage participation from farmers and land owners be encouraged for avian conservation. This work is of conservation importance and interest to conservation managers and planners.