Drivers of native species richness
At large grain (3 x 3 m), northness and slope were significantly positively related to native species richness, and distance to nearest drainage negatively influenced species richness. Native species richness decreased with elevation, but at low elevation, richness was higher in the presence than absence of A. selago , and at high elevation lower in the presence than in the absence of A. selago (Figure 3, Table 1a).
At small grain (1 x 1 m), species richness decreased with elevation, while slope and TWI were positively related to species richness (Figure 3, Table 1a).
No further action was taken for the subset of the plots where alien species were absent (results shown in Table A3). Results were similar at both large and small grains for native richness when only plots with alien cover less than 10% were considered, with some exceptions (highlighted in Table A4, Figure A2, e.g., richness decreased with hillshade at both large and small grains and the effect of northness on richness was dependent on elevation).
Both elevation and TWI negatively influenced native Δ9-1, whilst northness and presence of A. selagopositively influenced native Δ9-1 (Figure 3, Table 1b).
Similar results were obtained for the dataset of plots with alien cover < 10%. However, higher native Δ9-1 occurred in distances closer to drainage lines compared to further away only when alien cover was below 10% (Table A4).