Resource availability
Based on measurements in 2013, community successional stage was positively correlated with resident diversity (r = 0.679) and negatively correlated with soil nitrate (-0.861; Table S7a). Effects of disturbance on soil N varied with successional stage (Table S7b-d, Fig. S6); disturbed plots had lower soil N than undisturbed plots in early succession (r = -0.42), but higher soil N in mid and late succession (r = 0.64 and 0.44 respectively). Light levels at ground level declined with successional stage and time, and were higher in disturbed than undisturbed plots (r = 0.711), especially in mid and late successional communities (r = 0.90 and r = 0.95 respectively; Table S7, Fig. S8). Soil moisture was highest in late successional communities and lowest in mid successional communities (Fig. S7). Disturbed plots had lower soil moisture than undisturbed plots, especially in mid successional communities (r = -0.71) where soil moisture was already very low (Fig. S7). Apart from soil moisture, these correlations provide evidence that competition generally increased and availability of key resources, namely soil nitrate, decreased with succession.