Tree species compositional change and conservation implications in the white-water flooded forests of the Brazilian Amazon

摘要: Aim: The aim of this study was to use compositional changes in tree species along the Amazon River floodplain Brazil identify and characterize biogeographic regions that would serve as broad surrogates for conservation planning. Location: main course Brazil, covering a river distance approximately 2800 km. Methods: Two sampling methods were employed at specific sites: standardized transects and/or individual-based samples. Seventy-three samples collected from 26 sites 100-km intervals floodplain. Biogeographic identified by non-metric multidimensional scaling (NMDS) ordination hierarchical cluster analysis. relative influence environmental components (flood depths, annual rainfall, length dry season) on composition one spatial component (longitude) analysed multiple regressions against one-dimensional NMDS axis. Results: Based composition, three identified: western region between Tabatinga Negro confluence; central confluence Xingu an estuarine Santana. consistent using different data sets analytical techniques. Mixed effects explained most variation, but effect alone had greater than alone. Main conclusions: delimited analyses differed those based geomorphology or World Wildlife Fund (WWF) ecoregions. These results reinforce need be tested biological before they are used shape approaches planning. Although protected area coverage 25% gives impression extensive management floodplain, less 1% Amazon's is strictly protected. significant differences strong variation indicate strict protection areas should distributed much more evenly within regions.