THE UTILITY OF BIRDS AS BIOINDICATORS - CASE-STUDIES IN EQUATORIAL AFRICA

When site quality cannot be fully studied, due to lack of time or avai lable specialists, the use of particular species as indicators has bee n proposed. However, species which indicate species-richness are neede d for appreciation of biodiversity, whereas widespread stenotopic spec ies are appropriate for habitat quality. Birds are potential bioindica tors, uniting inherent biological and methodological advantages. Birds can only be bioindicators of habitat quality if they occur in the sam e habitat in all the sites under consideration. Standard bird counts a nd captures, and standard measurements of habitat-characteristics take n along chosen transects, yield avifaunal composition and relative den sity in pristine and man-changed areas in equatorial Africa, in two co mplex areas situated in the historical forest belt (Zaire and Cameroon ). The use of these data for bioindication was examined. Segregation w as found to be highest in undisturbed sites within the mosaic of prese nt-day habitats. The present study proposes, for this particular regio n, the use of proportions in relative density of four common species a mong a particular family, the bulbuls, which all are well-characterize d according to habitat. Nevertheless, the authors are fully aware that this indicator cannot be extended to other regions.