Results
Out of the 464 plots sampled, 95 plots contained alien species (Figure 1). At the large grain, maximum species richness was six per plot (mean = 2.81 ± 1.33), whilst at the smaller grain it was five native species per plot (mean = 1.99 ± 1.03). The maximum native Δ9-1was four species per plot (mean = 0.82 ± 0.87). On the other hand, maximum alien species richness per plot was three at the large grain (mean = 0.23 ± 0.49), and two at the small grain (mean = 0.13 ± 0.35). The maximum alien Δ9-1 was two (mean = 0.10 ± 0.34) (Figure 2).