Modelling the climate suitability of green carpenter bee (Xylocopa aerata) and its nesting hosts under current and future scenarios to guide conservation efforts (vol 45, pg 271, 2020)

Due to local extinction, the endangered green carpenter bee (Xylocopa aerata) has a disjunct distribution in the southeast of Australia. The species relies on dead softwood from a small selection of plant species for making its nests. Habitat fragmentation, combined with deleterious fire events, is thought to have negatively impacted on nesting substrate availability and recolonisation chances. Here, we use MaxEnt algorithm to model both the current distribution and the effect of climate change scenarios on the distribution of both X. aerata and four plant species that provide most of its nesting substrate: Banksia integrifolia, B. marginata, Xanthorrhoea arborea and Xanthorrhoea semiplana subsp. tateana. The annual mean temperature is the strongest climatic predictor of the distribution of X. aerata and its host plants. The modelled distribution of the bee under current climatic conditions indicates that climatic factors are unlikely to cause local extinctions. In all future scenarios, suitable areas for X. aerata and each of its nesting hosts are expected to contract towards the southeast of mainland Australia. The suitability of Kangaroo Island for the bee and its current local current host species is maintained in all scenarios, while Tasmania will become increasingly suitable for all species. The Grampians National Park in western Victoria, where the bee species were last seen outside of its current range (in the 1930s), is predicted to remain suitable for X. aerata and several host plants under all scenarios. Therefore, this relatively large area of native vegetation may be a good case study for re-introduction as part of future conservation efforts.