Shepard, Yu &Nelson (2004) “Ethnobotanical ground-truthing and forest diversity in the Western Amazon” Advances in Economic Botany 15: 133-171. 1 Ethnobotanical Ground-Truthing and Forest Diversity in the Western Amazon Glenn H. Shepard Jr., Instituto Nacional de Pesquisas da Amazônia 1 Douglas W. Yu, Imperial College at Silwood Park 2 Bruce W. Nelson, Instituto Nacional de Pesquisas da Amazônia cite as: Shepard, G.H Jr., D.W. Yu and B.W. Nelson (2004) “Ethnobotanical ground-truthing and forest diversity in the Western Amazon.” In: Ethnobotany and Conservation of Biocultural Diversity. Carlson, T.J.S. & L. Maffi, Eds. New York: New York Botanical Gardens. Advances in Economic Botany 15: 133-171. Abstract: In this study, we draw on the ecological knowledge of the Matsigenka indigenous people of the Peruvian Amazon as a template for interpreting satellite images and assessing rain forest habitat diversity, in a process we have dubbed “ethnobotanical ground-truthing.” Recent assessments of LANDSAT images of the Peruvian Amazon suggest rain forest habitat diversity may have been historically underestimated. Yet there exists little empirical evidence to support this assertion, and satellite images alone prove problematic in accurately distinguishing habitats on the ground. An ethnoecological study among the Matsigenka reveals a complex system of habitat classification based on vegetative and other biotic features as well as topographic, hydrological, and edaphic characteristics, and disturbance regimes. The Matsigenka distinguish some 69 vegetationally-defined habitats (some of which overlap) and 29 abiotically-defined habitats, as well as ten soil types and at least seven habitats associated with specific faunal indicators. The Matsigenka recognize all forest types currently known to ecologists working in the region, and also distinguish some types not apparently known to ecologists. Several forest types recognized by the Matsigenka have, as their dominant species, trees previously considered rare. Estimates of forest diversity based on indigenous knowledge suggest forty to fifty distinct natural habitat and micro-habitat types for the Manu river alone, at least triple the number previously recognized. Scientists working in this and other tropical forest areas with indigenous populations might benefit from collaboration with ethnobiologists and local communities. Ethnobotanical ground-truthing may ultimately contribute to our understanding of the diversity and dynamics of tropical forests. 1 Address correspondence to G.H. Shepard Jr. c/o da Silva, Conj. Villar Camara, R. 3 C. 105, Manaus AM 69083-000 BRAZIL. email: ghs@inpa.gov.br 2 Address correspondence to D.W. Yu, School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK. email: d.yu@ic.ac.uk