Natural vegetation cover in the landscape and edge effects: differential responses of insect orders in a fragmented forest

GONZÁLEZ, E.; SALVO, A., FENOGLIO, M. S., VIDELA, M.; VALLADARES, G. R.

INSECT SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016

1672-9609

Human activities have led to global simplification of ecosystems, among which Neotropical dry forests are some of the most threatened. The reduction of non-crop habitats in the landscape as well as edge effects may affect insect communities. Here, we analyzed insect communities sampled with broad spectrum pan traps in nine landscapes comprising cultivated fields and Chaco Serrano forests, at overall community and taxonomic order level. In total 7,043 specimens and 456 species of hexapods were captured, and we found that abundance and richness were directly related to forest cover and higher at edges in comparison with forest interior. Community composition also varied with forest cover and edge/interior location. Different responses were detected among the eight dominant orders, albeit none responded negatively to forest cover or edge location. Collembola, Hemiptera and Orthoptera richness and/or abundance were positively related to forest cover, while Thysanoptera abundance also increased with forest cover, but only at the edge. Coleoptera, Diptera and Hymenoptera were more diverse and abundant at the edge. The negative influence of forest loss on insect communities could have functional consequences for both natural and cultivated systems, and highlights the relevance of forest conservation. The higher diversity of insects at the edges could result from the simultaneous presence of forest and matrix species, although ?resource mapping? could be involved for orders that were richer and more abundant at edges. Adjacent crops could benefit from forest proximity since natural enemies and pollinators are well represented in the orders showing positive edge effects.