A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

TREE SPECIES DISTRIBUTION AND COMMUNITY STRUCTUREOF CENTRAL AMAZON VÁRZEA FORESTS BYREMOTE SENSING TECHNIQUESWITTMANN, F. 1 , JUNK, W. J. 1 & PIEDADE, M. T. F. 21 Max-Planck-Institute for Limnology, P.O. Box 16524306 Plön, Germanye-mail: florian@inpa.gov.br, wjj@mpil-ploen.mpg.de2 Instituto Nacional de Pesquisas da Amazônia, P.O. Box 457Av. André Araújo 2936, 69083-000 Manaus/AM, Brazile-mail: maitepp@internext.com.brThe large-scale estimation of forests biomass and primary production depends on a reliableclassification of diferent forest types. In Amazonian white-water floodplains (várzea), thedistribution of tree species is determined by their tolerance to flood stress. This leads to acharacteristic zonation of tree species along the flood gradient. Frequent disturbance bysedimentation, erosion and human impact result in a complex pattern of forest formationsof different successional stages. The formations are characterized by typical patterns ofspecies composition, and their architecture results in different light reflectance patterns,which can be detected by Landsat TM image data. Ground checking comprised a detailedforest inventory of 5 ha in várzea forests of the Mamirauá Reserve (Tefé) and Ilha daMarchantaria (Manaus). Digital Elevation Models (DEM) for all sites were generated. Theresults indicate that, at the average flood-level of 3 m, species diversity and architecture ofthe forests changes, thus justifying the classification into the categories of low várzea andhigh várzea. In a first step to scale up field-research data to a regional scale, the study siteswere observed by aerial photography. Tree heights, crown sizes, gap frequencies and theprojected crown-area coverage provide information, which confirms a remotely sensedclassification into four different forest types. The structure of low várzea depends on thesuccessional stage, and species diversity increases with increasing age of the formations. Inthe high várzea, species diversity is higher than in all low-várzea formations. The morecomplex architecture of the high-várzea results in a more diffuse behavior pattern in pixeldistribution, when classified by TM image data.