Future‐proofing the koala: Synergising genomic and environmental data for effective species management. Issue 11 (19th April 2022)

• Record Type: Journal Article
• Authors: Lott, Matthew J.; Wright, Belinda R.; Neaves, Linda E.; Frankham, Greta J.; Dennison, Siobhan; Eldridge, Mark D. B.; Potter, Sally; Alquezar‐Planas, David E.; Hogg, Carolyn J.; Belov, Katherine; Johnson, Rebecca N.
• Editors: Waits, Lisette
• Is Part Of: Molecular ecology. Volume 31:Issue 11(2022)
• Page Start: 3035
• Page End: 3055
• Publication Date: 2022-04-19
• Subjects: candidate genes -- conservation genomics -- exon capture -- local adaptation -- Phascolarctos cinereus -- phylogeography; Molecular ecology -- Periodicals; Molecular population biology -- Periodicals; 576
• DOI: 10.1111/mec.16446
• Languages: English
• ISSNs: 0962-1083

Abstract

Abstract: Climatic and evolutionary processes are inextricably linked to conservation. Avoiding extinction in rapidly changing environments often depends upon a species' capacity to adapt in the face of extreme selective pressures. Here, we employed exon capture and high‐throughput next‐generation sequencing to investigate the mechanisms underlying population structure and adaptive genetic variation in the koala ( Phascolarctos cinereus ), an iconic Australian marsupial that represents a unique conservation challenge because it is not uniformly threatened across its range. An examination of 250 specimens representing 91 wild source locations revealed that five major genetic clusters currently exist on a continental scale. The initial divergence of these clusters appears to have been concordant with the Mid‐Brunhes Transition (~430 to 300 kya), a major climatic reorganisation that increased the amplitude of Pleistocene glacial‐interglacial cycles. While signatures of polygenic selection and environmental adaptation were detected, strong evidence for repeated, climate‐associated range contractions and demographic bottleneck events suggests that geographically isolated refugia may have played a more significant role in the survival of the koala through the Pleistocene glaciation than in situ adaptation. Consequently, the conservation of genome‐wide genetic variation must be aligned with the protection of core koala habitat to increase the resilience of vulnerable populations to accelerating anthropogenic threats. Finally, we propose that the five major genetic clusters identified in this study should be accounted for in future koala conservation efforts (e.g., guiding translocations), as existing management divisions in the states of Queensland and New South Wales do not reflect historic or contemporary population structure.