Habitat loss, cattle, and community-level patterns
Species richness increased with both forest patch area (Fig. 2B) and
habitat amount (Fig. 2D) and decreased with cattle intrusion (Fig. 2C).
The effect of cattle is likely to be underestimated when species
detection is not taken into account: when using occupancy models, cattle
presence was estimated to locally extirpate an average of 26 ant
species, whereas a naïve species count would estimate a reduction of
only 14 species.
Due to the relatively high number of missing species due to sampling
effects (low detection), pairs of patches were estimated to be more
similar to each other in species composition than a naïve measure of
species similarity (Fig. S14). Unexpectedly, the pairwise similarity in
species composition was positively associated with geographic distance
(Fig. 4A), and differences in patch size (Fig. 4B) and habitat amount
(Fig. 4C). We did not find evidence that differences in cattle intrusion
affected the similarity in species composition (Fig. 4D). When using raw
(uncorrected) similarities, the effect of geographic distance was
qualitatively similar, whereas no effects of patch size and habitat
amount could be detected (Fig. S15). Cattle was only weakly associated
with species similarity when the Jaccard index was measured using raw
data (r2 = 0.04 for the turnover component; Fig. S15).