IMBIV   05474
INSTITUTO MULTIDISCIPLINARIO DE BIOLOGIA VEGETAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Responses of insect herbivores to habitat fragmentation: a meta-analysis
Autor/es:
ROSSETTI MARIA ROSA; TSCHARNTKE TEJA; AGUILAR RAMIRO
Lugar:
Montpellier
Reunión:
Congreso; 27th International Congress for Conservation Biology; 2015
Resumen:
Insect herbivores are recognized as an important component of all ecosystems as they can impact plant growth and reproduction, thus affecting plant community structure and diversity. Several studies have evaluated how herbivore species richness and abundance as well as plant damage by insects are affected by habitat fragmentation. In general they found that habitat loss and habitat isolation decreases species richness and density of herbivores, and consequently reduces insect herbivory. However, other studies have shown the opposite trend or did not find any significant relationship. In addition to direct effects, indirect top-down as well as bottom-up processes can be expected to change with habitat fragmentation. Small fragments support fewer plant species and thereby, reduced associated resistance, potentially leading to higher herbivore and herbivory levels. Since natural enemies, which may control herbivore populations, can be more vulnerable to fragmentation than herbivores there. Here we test in a meta-analysis the effects of habitat fragmentation (fragment area, isolation and fragmentation per se) on abundance and species richness of herbivores and on herbivory levels. We considered insect herbivory at the plant species levels, but also the community level. In the course of a systematic review we found 82 suitable studies evaluating the effects of habitat fragmentation on abundance and species richness of herbivores and on herbivory levels in a range of ecosystems: ranging from tropical forests to grasslands. Across all studies, habitat fragmentation had a negative effect on insect herbivory. This result indicates that reduction of species richness and density of herbivores is more driven by direct effects of habitat fragmentation than by indirect bottom-up or top-down effects. Our meta-analysis can provide a better understanding of the responses of insect herbivores, and the process in which they are involved, to landscape modification.