MAPPING OF BIOLOGICAL DIVERSITY IN SAHEL BY MEANS OF SATELLITE IMAGE ANALYSES AND ORNITHOLOGICAL SURVEYS

Through analysis of biological data and satellite images from the Ferl o region in Northern Senegal, the correlations between remote sensing data and biological diversity have been tested. Data on a number of bi ological and abiotic factors have been compared with different analyse s of LANDSAT TM and NOAA satellite images. Biological diversity has ma inly been measured through ornithological surveys in the dry seasons 1 991-1993. Correlations are obtained between different measurements for avian diversity and the combination of a landscape diversity index ba sed on a LANDSAT TM pixel analysis, and the yearly biomass production expressed by INDVI for the study areas (multivariable coefficient of d etermination r(2) ranging from 0.35 to 0.56). A multiple regression mo del, based on 10 different parameters from the study sites, can explai n 59-68% of the variation in avian species richness, number of individ uals and Simson diversity index. The following factors are significant ly involved in explaining the model: latitude, LANDSAT TM landscape di versity indices, plant biomass, bare ground, herbaceous and woody vege tation. Explaining factors vary in relation to the avian parameter use d in the model, but in general latitude (-), LANDSAT TM landscape dive rsity indices (+) and bare ground (+) are significant factors in all m odels. Based on the positive multivariable regression between avian di versity and features of LANDSAT TM and NOAA images, a biodiversity map has been produced for the Ferlo region. This map can be one layer of a future integrated conservation strategy for the Ferlo region. Limita tions for the interpretation of the map, and recommendations for impro vement of the data gathering and analyses in similar studies, are disc ussed.