Large terrestrial mammals are facing immense population declines due to habitat loss and fragmentation, which will have profound effects on their associated ecosystems. The white-lipped peccary (Tayassu pecari), a large, herd-forming, forest ungulate, is known to greatly affect its environment through trophic and non-trophic top-down interactions. Here, we evaluated how local extinction of white-lipped peccaries influences forest structure, density, and diversity. Using white-lipped peccary GPS movement data and local knowledge from rural landowners, we chose 11 locations where white-lipped peccaries intensively and frequently used and 7 locations where white-lipped peccaries were known to be locally extinct, and quantified forest size structure, density, and diversity. At each location, we sampled plant size (diameter at breast height – DBH), plant density, and plant diversity. We separated plants in three size categories: adult trees (individuals with DBH greater than 30 cm), which were sampled in 20 x 20 m plots; tree saplings (individuals taller than 1 m, and with DBH smaller than 30 cm), which were sampled in a 10 x 10 m plot within the 20 x 20 m plot; and seedlings (individuals shorter than 1m) which were sampled in four 1 x 1 m plots within the 20 x 20 m plot.
Results/Conclusions
We found slightly larger DBH for adults (P = 0.07), and significantly smaller DBH for saplings (P <<< 0.001) in areas where white-lipped peccaries were present. We also found greater sapling density in plots where white-lipped peccaries were present (P = 0.06), but no difference in adult and seedling density between plots with and without peccaries. Slightly larger adult trees may indicate that white-lipped peccary prefer forest patches with larger trees, which could produce more fruits. More and smaller saplings in areas where white-peccaries are present may be a reflection of frequent disturbance. The unexpected lack of difference in seedling density could be due to a short-term mortality effect from sampling during the dry season. Diversity differences could not be properly evaluated as individual-based rarefaction curves showed that sampling effort must be increased. Overall, our results indicate that white-lipped peccaries may have lasting disturbance effects through their frequent visitations, but such effects are more clearly seen at the sapling stage, not the seedling stage. Further analysis in multiple forest types (e.g.riparian zones, dry forest, palm swamps) will clarify whether white-lipped peccary effects are habitat dependent.