Effects of collared peccary (Pecari tajacu) exclusion on leaf litter amphibians and reptiles in a Neotropical wet forest, Costa Rica

Abstract

Peccaries are known to shape vegetation structure and create important breeding habitat for some pond-breeding amphibians in Neotropical forests. Because peccaries are also important agents of disturbance and microhabitat variation in the litter, peccary loss could have important consequences for litter amphibians and reptiles that depend entirely upon the litter for shelter, foraging and reproduction sites, and thermoregulation. However, very little is known about the effects of peccaries or their loss on litter amphibians and reptiles. We experimentally reduced peccary density in 20×50m fenced exclusion plots (n=5). We compared standing litter structure and amphibian and reptile abundance where peccaries were excluded to paired, open-forest control plots that had natural peccary densities. We encountered 16% more amphibian and reptile individuals in open control plots, and we encountered more juveniles of the most common anuran species in control plots than on peccary exclusions. Control plots had more compacted litter than peccary exclusion plots, indicating that peccaries alter the physical structure of the standing leaf litter in a way that promotes greater recruitment of juvenile anurans. Our results demonstrate that peccaries should be viewed not just as seed predators or ecosystem engineers for palms and pond-breeding amphibians, but also as important agents that affect leaf litter structure and abundance of terrestrial amphibians and reptiles. Peccary extirpation from overhunting or habitat degradation could have unexpected negative consequences for litter amphibians and reptiles, a diverse group already severely threatened by habitat loss, climate change, disease, and other anthropogenic effects worldwide.