Can intensively managed plantation forests support a diverse arthropod fauna?

Plantation forests constitute a large proportion of the forest estate in many countries, particularly in the temperate regions of Europe. In addition, large scale deforestation has led to the fragmentation of natural forests within heavily managed agricultural landscapes. In light of this, it is important that the potential of plantations to support a diverse flora and fauna, particularly of forest specialist species, is assessed. We compared arthropod diversity in mixed and single species plantations of non-native conifers to that in native woodlands in forty five stands across Ireland. Spiders and Carabid beetles were sampled with pitfall traps and a range of environmental parameters were measured including vegetation cover, stand structure, soil attributes, and landscape variables such as forest cover. Invertebrate species composition and richness differed between plantations and native woodlands, particularly for key forest-associated species. Responses also differed by taxonomic group. At the stand scale arthropods were related to litter and vegetation cover, whereas large scale variables such as amount of forest cover within 5km were not important. These findings suggest that forest policy aimed at promotion of biodiversity in plantations should support greater diversity of stand structure and tree species composition. The planting of more species of native provenance should also be encouraged.