Insect community reassembly in a spatiotemporally heterogenous restoration landscape

Abstract

Abstract Context Anthropogenic habitat degradation resulting from agricultural, mining, and urban development is a leading cause of global insect declines, but the recovery of insect communities and functional guilds is rarely assessed during ecological restoration. Objectives Assess the effects of vegetation community composition and structure on insect species richness, diversity, and abundance across various stages of ecological restoration to understand the patterns and drivers of the return of insect functional guilds to post-mining restoration landscapes. Methods We sampled the insect community using ultraviolet polypropylene vane traps and conducted floristic surveys to quantify the relationships between the insect community and vegetation community across a 40-year sequence of post-mining ecological restoration in south-western Western Australia. Results Despite the lack of convergence observed in the vegetation community, insects returned through natural processes of reassembly and dispersal such that the community resembled that of reference forest communities within approximately a decade of restoration activity. However, the insect community transitioned from an assemblage dominated by pollinators to one dominated by herbivores and detritivores along the ecological restoration age gradient. Our results indicate that plant abundance had a significant effect on the abundance of pollinators and parasitoids but the relationships between vegetation community metrics and other functional guilds were relatively weak. Conclusions Insect functional guilds present complex and variable responses to vegetation re-assembly and maximising landscape spatiotemporal heterogeneity and habitat complexity in ecological restoration can increase the availability of suitable habitat for a diverse suite of insect taxa and the associated ecological services they provide.