Understanding the maintenance of high tropical tree species diversity requires disentangling the effects of habitat vs. geographic distance. Using floristic, topographic, and soil nutrient data from 105 0.6-ha plots in mixed dipterocarp forest throughout Sarawak, Malaysian Borneo, we explore the degree to which floristic patterns are habitat-driven from local to landscape scales. We assess how the floristic influence of geographic distance vs. abiotic factors varies from local to regional scales. We employ several multivariate analytical techniques and perform a hierarchical clustering of the research plots using the Steinhaus index of floristic dissimilarity, as well as Mantel analyses on matrices of floristic, habitat, and geographic distance. These analyses indicate that floristic variation is more strongly correlated with habitat than with geographic distance on the regional scale. On the local-landscape to community scale, we find evidence of a resource threshold above which habitat effects weaken; that is, below the resource threshold floristic similarity between sites is dominated by habitat effects, while above the threshold floristic similarity between sites is dominated by geographic-distance effects. We also find evidence that topography and soil nutrients correlate in part independently with floristics. These results, together with previous studies in the Neotropics, emphasize that tree species distribution and community composition are variously influenced by the interplay of both habitat and dispersal-driven effects.

Metadata fileA metadata file describing the contents of the data. There are six data files in total associated with this dataset. This metadata file provides background information on each data file, as well as a full description of the various fields included within the files.Site dataData describing the sites of plot samplingsarawak_sites.csvSoils dataData on soil chemistry, texture and colorsarawak_soils.csvSpecies dataA listing of species found within all plotssarawak_species.csvTopography dataData on site topographysarawak_topo.csvTrees dataData on height, girth, and buttress attributes of tree individualssarawak_trees.csvForest profile dataData of height, girth and height to first branch for construction of profile diagramssarawak_profiles.docxAll data filesA zip file including all six (sites, soils, species, topography, trees & profile) data files.mdfData.zip