The restoration of degraded ecosystems often focuses on reestablishing species richness and diversity of native organisms, especially plants. However functional trait descriptions of communities are emerging as a more comprehensive approach to evaluating restorations, including consumer communities. We examined the species composition and functional traits of dung beetle communities across a chronosequence of restored tallgrass prairie in Illinois, including sites with and without bison and prescribed fire. Data were collected on behavioral guild, diel activity, and body measurements, and functional diversity metrics (functional richness, evenness, and dispersion) were analyzed using generalized linear models. We also performed a dung decomposition experiment to measure an ecosystem function driven by these insects.
Results/Conclusions
Older restorations demonstrated higher levels of dung beetle functional richness and dispersion more similar to remnant sites than newer restorations. Restored sites with bison had greater functional richness and dispersion of dung beetle species, as well as faster rates of dung decomposition, than similar-aged sites without bison. Prescribed fires interacted with the presence of bison to influence functional richness, dispersion, and dung decomposition. We conclude that measures of functional diversity are more appropriate for evaluating the success of tallgrass prairie restorations because they indicate the restoration of ecosystem functions, rather than simply the presence or absence of species. Our research also reinforces the use of dung beetles as indicators of functional restoration in grasslands. We recommend that restoration managers consider the arthropod community and its functional characteristics when making management decisions.