FIGURE 5 Distance decay of community similarity across the Quercus alnifolia (Qa) habitat. Distances among Qa sampling sites were calculated either based on the
isolation-by-resistance (IBR) scenario reflecting the spatial
distribution of Qa forest patches (FRAIBR, left
panel) or on the topoclimatic distances among sampling sites
(ENVPC1-2, right panel). Community similarity was
estimated using the Simpson similarity index (1 - βSIM)
at ASV (filled circles, solid regression line) and OTU (open circles,
dashed regression line) levels. For display purposes, the decay curves
were fitted using generalized linear models (GLMs) with a negative
exponential function. Regression slopes, coefficients of determination
(pseudo-R 2) and p-values are provided on
the top of each panel. See Table 3 for multivariate matrix regression
analyses assessing the independent contribution of each predictor to
community dissimilarity.