WHAT SATELLITE IMAGERY AND LARGE-SCALE FIELD STUDIES CAN TELL ABOUT BIODIVERSITY PATTERNS IN AMAZONIAN FORESTS

The great problem in biodiversity studies in Amazonia is that the exis ting data are regionally very biased, whether the question is about sp ecies distribution patterns, local species diversity levels, or differ ences in species diversity and species composition among sites. The su rroundings of a fev: cities and biological stations are relatively wel l inventoried, while most of Amazonia still remains unknown in these r espects. The essential questions are, to what extent can these data he extrapolated, and from where do we most urgently need more data? Quan tifying biodiversity is not just a question of how many species there are in one hectare. It is also a question of how many different habita ts there are, how much the floras of the different habitats differ fro m each other, and how many species there are in a given region as a wh ole. Satellite images are invaluable in studying such regional variabi lity, because they provide an overview of wide areas, even inaccessibl e ones. The color patterns in satellite imagery enable one to identify and map areas that differ in some way; field studies are then needed to find out whether these differences are significant in ecological an d Aoristic terms. Satellite imagery from Peruvian Amazonia shows varia tion to such an extent that hundreds of sites need to be studied to do cument and understand it. Because it would take too much time to ident ify the thousand or so plant species that can be found in a single hec tare of forest. we have developed an inventory method based on indicat or species. This makes it possible to monitor large areas relatively r apidly and has revealed some intriguing ecological anti biodiversity p atterns in Amazonia.