Are roadside strips important reservoirs of invertebrate diversity? A comparison of the ant and beetle faunas of roadside strips and large remnant woodlands

Abstract

Pitfall traps were used to sample the terrestrial ant and beetle fauna of four large State Forests and five roadside strips of white cypress pine woodland in the wheat belt of central western New South Wales. In total, 93 morphospecies of ant and 82 morphospecies of beetle were identified. The species richness and total abundance of both ants and beetles did not differ significantly between roadside strips and large State Forests. Multivariate analyses detected significant differences in community composition of the ant and beetle faunas of large State Forests and roadside strips of vegetation. Differences in ant community composition were similar regardless of whether the analysis was conducted at the species or genus level. Differences in beetle community composition were significant at the family level, but not at the species level, possibly because sampling intensity at the species level was sub-optimal. There was no significant correlation between ant species richness and beetle species richness, nor between total abundance of ants and total abundance of beetles. However, there was a significant correlation between site similarity assessed according to ant community composition and beetle community composition. Of the species found in the large State Forests (presumed woodland species), 69% of ant species and 64% of beetle species were found in roadside strips of vegetation. This suggests that even though the two habitat configurations may support different communities, narrow strips of vegetation still represent useful habitat for many species of woodland invertebrates. They therefore have considerable potential both as conduits of gene flow and as reservoirs of biodiversity in highly fragmented landscapes