Figures 3a-d. Metrics of familial distributions along elevational gradients, used to test mechanisms shaping the slope of ERR via cross-family analyses.
Each point represents a species-rich plant family (n = 60), with size of point representative of Malesian richness . Three families labeled as examples for comparisons between scatterplots: 1) Dipterocarpaceae, 2) Ericaceae, 3) Pteridaceae. On the y-axis, slope of average elevational 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 richness and elevational distribution. Plots include a) the localized richness ratio , which is defined as the greatest richness observed at any section of the elevation gradient, divided by total family richness across all of Malesia; b) elevation with peak in richness (highest point of the predicted richness curve); c)familial elevational extent (breadth of the richness curve), calculated as the highest elevation minus the lowest elevation values for any species within a family; d) the average upper elevational limit for species occurrence. Other metrics not shown include e) Malesian richnessand f) average lower elevational limit . 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.