Growth and distribution of lowland rainforest tree species in eastern Madagascar

Since the 1980s, Madagascar has received international attention out of concern for the possible extinction of its unique biota.  The island, which has less than seven percent of original primary forest remaining, is in danger of complete ecological breakdown. Home to some of the last and largest expanses of primary rainforest in the country, the east coast of Madagascar has experienced significant deforestation and subsequent fragmentation due to slash and burn agriculture.  Attempting to conserve the biodiversity of its rainforests requires a comprehensive understanding of the physiological impacts of human and abiological disturbances on Madagascar's remaining forests. 

            The objectives of this doctoral research are to utilize a focused dataset to characterize the growth and distribution of endemic tree species as they exist in the primary and secondary forest of Betampona Reserve, located on the east coast of Madagascar. Comprehensive fieldwork collection has been accomplished through repeat study of 100 plots, 250 band dendrometer growth rate collections, wood density sampling, techniques in soil nutrient analysis and spatial rectification using GPS.  Multivariate statistical analyses of tree species composition with topographic data indicate that rates of growth and occurrence of the 231 species found within the 2,200 hectare reserve correlate with altitude and soil composition. Controls on average growth of dominant species within the forest will be revealed through direct gradient analyses of topographic position and soil nutrient concentrations (C:N and PA-P). These findings will provide the first analysis of tree species composition, growth rate, and soil nutrients of the study region. Relative growth rates recorded from the band dendrometer study will be used with environmental and plot data in a further multi-tiered modeling study of functional type data aggregation techniques; the goal of which will be to construct a Madagascar rainforest specific growth and distribution model for future conservation and management efforts.