Figure 4a-d. Metrics of biogeographical overlap and endemism, used for across-family analyses on the mechanisms shaping the slope of ERR.
Each point represents a species-rich plant family (n=60), with size of point representative of family richness. Three families labeled as examples for comparisons between scatterplots: 1) Dipterocarpaceae, 2) Ericaceae, 3) Pteridaceae. On the y-axis, slope of average elevation range-size (m), abbreviated as ERR, as a function of position along an elevational gradient (m a.s.l.). On the x-axis, familial metrics of distribution by Malesian biogeographical region (Sundaland, Wallacea, or Sahul), with values ranging from 0 - 1. Plots 4a-c representendemism , defined as the proportion of species that exclusively occur within a single biogeographical region. Plot 4d representscosmopolitanism , defined as the proportion of species that occur in all three biogeographical regions. Not shown is the overlapmetric, defined as the proportion of species occurring within a given biogeographical region and with the potential to occur elsewhere, summarized in Table 1. Linear regression results shown as a black slope, phylogenetic independent contrasts as a red slope, both plotted without scaling; dashed lined represent non-significance. Point colors (CMYK model) represent the combined metrics of biogeographic association of each family, with endemism to Sundaland represented as magenta tones, Wallacea as yellow, Sahul as cyan, and cosmopolitan as black, with 25% transparency. Full color legend for the 60 families in Supporting information.