|Aim: Contemporary climate change is predicted to impact all levels of biodiversity, including intraspecific genetic diversity, the evolutionary basis for future adaptation. While numerous studies use species distribution models (SDMs) to predict speciesí future distributions, relatively few investigate potential climatic impacts on the spa-tial structure of genetic diversity, and how it varies across species ranges. We revis-ited phylogeographic data for three New Zealand forest beetles to predict the effects of climate change on the geographic distributions, genetic diversity and phylogeo-graphic structure for each species.
Location: New Zealand
Methods: We used ensemble SDMs to predict potential distributions for Agyrtodes labralis (Leiodidae), Brachynopus scutellaris (Staphylinidae) and Epistranus lawsoni (Zopheridae) in 2035, 2065 and 2100. To assess the impact of predicted range loss on genetic diversity and phylogeographic structure, we estimated haplotype and nu-
cleotide diversity, FST, Average Taxonomic Distinctness (AvTax), Phylogenetic Diversity (PD) and Net Relatedness Index (NRI) under current and future climatic scenarios, excluding sequences from localities predicted to become unsuitable. We tested whether predicted population loss was spatially clustered and how losses were distributed across the phylogenies of each species.
Results: Agyrtodes labralis is predicted to lose parts of its current distribution by 2100, with the loss of 50% of unique haplotypes and a significant reduction in PD, while Brachynopus scutellaris and Epistranus lawsoni will likely experience an expan-sion in climatically suitable area and little change in genetic diversity. Brachynopus scutellaris populations are predicted to be more phylogenetically clustered than ex-pected by 2100, but changes in AvTax were negligible for all species.
Main conclusions: We demonstrate that the loss of genetic diversity under climate change is significant; however, intraspecific lineages with deep genetic divergences are widely distributed, buffering against greater change in phylogeographic struc-ture. For species with strong geographic clustering of genetic diversity, climate change impacts may be quite different.|