Extended Data Figure 4 : Measuring phylogenetic dispersion of grassland communities.

From: Phylogenetic structure and host abundance drive disease pressure in communities

Extended Data Figure 4

a, b, Phylogenetic dispersion analysis from one representative site. Open circles show the observed phylogenetic distance among the 29 species found in grassland site 2, for each of 18 quantiles (from 0 to 50%). Grey circles show phylogenetic distance quantiles for random draws from the 529 species in the regional metacommunity (the UCSC campus) (a) or the 43 species found in the surrounding grassland community (b). Size of the grey circle is proportional to the number of times that distance was found in 10,000 independent random draws of 29 species. Solid blue lines show the observed phylogenetic distance at the 7% quantile; dotted lines show medians of the random draws. a, b, The observed distance was 74 Myr less than the median of the random draws from the regional metacommunity at the 7% quantile (that is, phylogenetic clustering, consistent with habitat filtering) (a), and the observed distance was 13 Myr greater than expected from random draws of grassland species only (that is, phylogenetic overdispersion, consistent with negative species interactions) (b). Statistical tests based on independent estimates of dispersion for each of the ten sites are shown in Extended Data Fig. 5.