Results
We found a total of 251 ant species, which represented about 85% of the diversity estimated across the entire study region (HDI range = [294, 327]; Fig. 2A). Approximately 45% of all species were observed at individual patches (observed range = [37, 80]; estimated range = [84, 177]; Fig. 2B-D). The large number of unobserved species, especially in individual patches, results from low detection of most ant species at individual Winkler extractors (Fig. 3A). Due to the larger number of patches and extractors across the entire landscape, the chance of detecting a rare species at least once increases with greater sampling effort (e.g. if Mycetomoellerius sp.6, one of the rarest species, is present, detection changes from ~1% at the Winkler extractor scale to ~9% at the patch scale, and to ~89% at the landscape scale). Even when considering detection errors, most species were rare across the landscape and occurred in fewer than 50% of all forest fragments (occupancy < 0.5 in Fig. 3B). These results demonstrate that any naïve counting of species (without the use of occupancy models or other corrections) would find more species at the landscape scale than at the local patches due to detection issues alone, even if no real changes in diversity occurred.
Estimates of regional species richness using the 500-m buffers or cattle intrusion as predictors in occupancy models provided almost identical results. Therefore, we were unable to detect an effect of the surrounding habitat amount on local diversity above and beyond what would be predicted by patch area alone (or the Species-Area Relationship). One additional species was estimated to be undetected in the landscape when cattle was used as a predictor when comparing with model with area as a predictor. Using the same sampling protocol, species were easier to detect in the smaller patches (i.e. smaller patches tend to more easily represented).