Microtopography and vegetation generate uneven predation pressure on forest insects

Abstract

Predation plays an important role in the coexistence of multiple species within forest ecosystems. It is spatially heterogeneous and influenced by the surrounding environment at different spatial scales. Studies focusing on multiple environmental factors in systems with high spatial complexity are lacking, but elucidating the effects of local environmental factors within a forest could assist in understanding the effects of local differences in predation pressures on multispecies coexistence. Here, we examined the effects of microtopography and vegetation on predation pressure using the model caterpillar method. We hypothesized that differences in microtopography and vegetation types would result in different predation pressures on invertebrates within a forest. Insect attacks were dominant throughout the study period. The attack rates on the model caterpillars were also lower on hill tops and evergreen deciduous trees. Predation pressure within the forest was heterogeneous and independently influenced by topography and vegetation type. Our results suggest that environmental heterogeneity within forests may lead to highly variable predation pressures and affect multispecies coexistence. This study suggests that microtopography and vegetation types within forests should be considered for biological control.