Advances in the understanding of ecosystem functioning under global change scenarios has created an opportunity to analyse the mechanisms underlying the impacts of land use on ecosystems. Land-use intensification and the associated shifts in ecosystem functioning have the potential to be managed in a way that can mitigate negative impacts on the environment. Modified landscapes in New Zealand are dominated by livestock farms, the majority of which are dedicated to cattle rearing for dairy and meat.
Large mammal herbivores did not evolve in New Zealand and recent introductions of cattle and sheep have resulted in an accumulation of detritus-rich dung, a valuable resource which has remained unexploited due to a lack of co-evolved detritivore fauna that specialise on large mammal dung. While there are native dung beetles in New Zealand, their assemblages are depauperate and restricted to native forest habitats, with feeding preferences towards native bird and reptile dung.
While non-native dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) were introduced to New Zealand in 2011 to utilise the large quantities of dung resources on pastures, there is still little knowledge about the long-term effects of these species on ecosystems. Previous programs introducing dung beetles to new habitat ranges have, so far, never explicitly measured the biotic and abiotic mechanisms that underlie the impacts of novel dung beetle assemblages on pasture ecosystems.
For this PhD, I will critically analyse (i) how the traits of introduced dung beetles affect functional efficiency, (ii) the physico-chemical responses to dung beetle activity that modulate ecosystem multifunctionality, and (iii) a meta-analysis of dung beetles and ecosystem functions. Identifying clear links between quantitative ecological traits and ecosystem functioning will allow for more effectively engineered dung beetle assemblages that benefit multiple biotic and abiotic processes to buffer the effects of land-use intensification on the supply of ecosystem services.