Fig. 3 The proportion of variance (% variation) in
compositional dissimilarity among plant communities
(βturnover, based on Simpson index) in each subset
(large/small genome size) as explained by environmental variables
(including MAP, MAT, altitude, soil N, and soil P) and geographical
distance using different genome size thresholds. Plant communities were
separated into the large- and small- genome size (1C DNA content, pg)
subsets by either the median (1.59 pg) or mean (3.19 pg) genome size for
the 161 species of the present study or from the median (2.50 pg) or
mean (5.90 pg) genome size of the global terrestrial plants in the Kew
database (see Materials and Methods ). Generalized dissimilarity
models (GDMs) were fitted using presence/absence data for the large-
(blue) and small- (yellow) genome size subsets. (a) Pure environmental
variation without a spatial component represents the effect of
environmental filtering. (b) Pure distance variation without an
environmental component can represent the effect of dispersal limitation
if all important environmental drivers are included in the environmental
component. (c) The ratio of variation explained by pure environmental
variation versus geographic distance was calculated, with estimates also
shown numerically on top of each bar. (d) Measured genome size for the
161 species ranked from small to large along the x-axis, with red dashed
lines indicating thresholds used in the analyses; the numbers inside
parentheses indicate the number of species in each group.