title: Responses of insect herbivores and herbivory to habitat fragmentation: a hierarchical meta-analysis.
abstract: Loss and fragmentation of natural habitats can lead to alterations of plant-animal interactions and ecosystems functioning. Insect herbivory, an important antagonistic interaction is expected to be influenced by habitat fragmentation through direct negative effects on herbivore community richness and indirect positive effects due to losses of natural enemies. Plant community changes with habitat fragmentation added to the indirect effects but with little predictable impact. Here, we evaluated habitat fragmentation effects on both herbivory and herbivore diversity, using novel hierarchical meta-analyses. Across 89 studies, we found a negative effect of habitat fragmentation on abundance and species richness of herbivores, but only a non-significant trend on herbivory. Reduced area and increased isolation of remaining fragments yielded the strongest effect on abundance and species richness, while specialist herbivores were the most vulnerable to habitat fragmentation. These fragmentation effects were more pronounced in studies with large spatial extent. The strong reduction in herbivore diversity, but not herbivory, indicates how important common generalist species can be in maintaining herbivory as a major ecosystem process.
authors.affiliation: Centro de Investigaciones Entomológicas de Córdoba. Instituto Multidisciplinario de Biología Vegetal (CONICET), Universidad Nacional de Córdoba, X5016GCA Córdoba, Argentina.
authors.forename: María Rosa
authors.initials: MR
authors.lastname: Rossetti
authors.affiliation: Agroecology, Georg-August University, 37077, Göttingen, Germany.
authors.forename: Teja
authors.initials: T
authors.lastname: Tscharntke
authors.affiliation: Instituto Multidisciplinario de Biología Vegetal (CONICET), Universidad Nacional de Córdoba, X5000JJC Córdoba, Argentina.|Laboratorio Nacional de Análisis y Síntesis Ecológica (LANASE), Universidad Nacional Autónoma de México, 58190 Morelia, México.
authors.forename: Ramiro
authors.initials: R
authors.lastname: Aguilar
authors.affiliation: Agroecology, Georg-August University, 37077, Göttingen, Germany.
authors.forename: Péter
authors.initials: P
authors.lastname: Batáry
mesh_terms: D000818:Animals; D003247:Conservation of Natural Resources; D017753:Ecosystem; D060434:Herbivory; D007313:Insecta / Q000502:physiology*
keywords: Body size; effect size; feeding type; fragment area; generalist herbivores; insect herbivory; isolation; spatial extent; species richness