Author(s): William E Magnusson, Albertina P Lim, Regina Luizo, Flvio Luizo, Flvia R C Costa
This study describes a modification of the 0.1 ha survey method developed by Gentry that we adapted for long-term ecological sites in the Brazilian Amazon. Our objectives were to develop a method that would be appropriate for long-term ecological studies (PELD component), but that would permit rapid surveys to evaluate biotic complementarity and land-use planning in Amazonia (RAP component). The philosophy behind the method is to maximize the probability of sampling adequately the biotic communities, for which large areas are needed, and at the same time minimize the variation in abiotc factors affecting these communities, that requires sampling small areas. To accomplish this, plots are long and thin, with their main axis oriented along topographical isoclines. This design minimizes topographical and soil variation inside plots and permits the use of these variables as predictors of species distributions. The design can be used for multiple taxa and life-stages, by adjusting plot width or taking composite sub-samples along the plot. The plots are arranged systematically on a trail-grid, which allows sampling of taxa that cannot be sampled in small plots. Each grid of trails and plots constitutes a research site. The systematic distribution of plots in the landscape allows unbiased estimates of species distributions, abundances and biomass for each site, and biogeographical comparisons between sites. Costs of implementation are moderate, considering the high output of integrated studies.