Fig. 4. Relationships of endophyte richness to seasonality remained robust when spatial factors, climate, vegetation, and host factors were considered.

Residual of species richness of endophytes in all hosts as a function of the residual of temperature seasonality (a) and residual of precipitation seasonality (b) after accounting for spatial factors, climate, vegetation, and host factors (a: R² = 0.03, p = 0.031; b: strongly approaching significance; p = 0.067, n = 106 biologically independent samples). These factors are described in full in “Methods” and Supplementary Methods. We illustrate the direct relationship of endophyte richness with temperature seasonality and precipitation seasonality in Fig. 3. Dotted lines represent 95% confidence interval.