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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. [ABSTRACT FROM AUTHOR]

The eastern quoll (Dasyurus viverrinus) is believed to be extinct on the Australian mainland, with the last confirmed record in 1963. Recently an eastern quoll specimen was located that had been found in northern Barrington Tops National Park (200 km north of Sydney) in 1989. Partial sequences (~200bp) of the mitochondrial DNA gene Cytochrome b were obtained from the Barrington Tops specimen and compared with sequences from known mainland and Tasmanian eastern quolls. The genetic data, while limited, are most consistent with the Barrington Tops specimen being derived from the 'extinct' mainland eastern quoll population. This suggests that eastern quolls survived for decades longer on the Australian mainland than previously thought and raises the possibility that they may still persist in remote areas such as Barrington Tops. [ABSTRACT FROM AUTHOR]

Aim Outside of Australia's Wet Tropics, studies of the biogeographical patterns of unglaciated Southern Hemisphere mesic environments are limited, and have primarily focused on herpetofauna. In this study mitochondrial DNA (mt DNA) and microsatellite (nu DNA) analyses were used to investigate the impact of biogeographical barriers on the evolutionary history of the widespread Australian marsupial Potorous tridactylus, as well as the effect of recent human-mediated habitat fragmentation. Location Australia; Queensland, New South Wales, Victoria, and Tasmania. Methods Three hundred and fifty-four individuals from 39 sites (representing 16 regional populations) across the species range were assessed for mt DNA Control Region and microsatellite (10 loci) variation. Genetic diversity, phylogeographical relationships and population structure were examined, as well as evidence for isolation by distance and past population expansion. Results Three highly divergent and reciprocally monophyletic mt DNA lineages were resolved (two mainland, one Tasmanian). A deep phylogeographical break, not associated with any obvious biogeographical barrier, was present on the mainland. Within the northern mainland and Tasmanian lineages, sub-structuring was coincident with the presence of physical barriers to gene flow. Fine-scale structuring was also present, with regional populations highly differentiated. Main conclusions This study expands on previous studies of Australia's mesic biome. Major phylogeographical breaks were identified, that dated to the Miocene (within the mainland) and Pliocene (isolation of Tasmanian), and differed from those described for the region's herpetofauna in age or location. The major mainland break appears species specific within this topographically complex region of Australia. Tasmanian populations were isolated from the mainland well before the most recent flooding of Bass Strait. Minor phylogenetic breaks within Tasmanian and northern NSW were associated with known biogeographical barriers. An absence of sub-structuring within the southern mainland lineage suggests extensive historical connectivity. The presence of regional population structure suggests that post-European settlement, local populations have become isolated and differentiated. [ABSTRACT FROM AUTHOR]

Fine-scale genetic structure was investigated in three regional populations of the long-nosed potoroo ( Potorous tridactylus) a threatened endemic marsupial. Two populations were from the Australian mainland and one from an island. Populations were sub-sampled at two sites, 6-8 km apart, connected by suitable habitat for dispersal. Factors influencing fine-scale structure were investigated by genotyping 157 individuals at 10 microsatellite loci and sequencing a ~621 bp region of the mtDNA control region. Results indicated that P. tridactylus populations exhibit significant intra-population structure, with significant F and Φ values recorded between subpopulations. This structure appeared mediated by small neighbourhood size, female philopatry and limited dispersal over 6-8 km, predominantly by males. Results highlighted several important features of P. tridactylus populations that have implications for conservation. Firstly, the small neighbourhood size suggests any investigations of intra-population structure should be conducted on a finer scale (e.g. 25-50 m) than many current monitoring programs. Secondly, the island populations were genetically depauperate, which may reflect processes occurring in many isolated 'mainland island' populations. Thirdly, the lower gene flow identified between populations separated by anthropogenically modified habitat suggests P. tridactylus is sensitive to changes in habitat configuration. [ABSTRACT FROM AUTHOR]

The potoroids are a small group of cryptic macropodoid marsupials that are difficult to directly monitor in the wild. Consequently, information regarding their social and mating systems is limited. A population of long-nosed potoroos (Potorous tridactylus) on French Island, Victoria, was monitored from June 2005 to August 2010. Tissue samples were collected from 32 (19 x, 13 y) independent potoroos and 17 pouch young. We aimed to determine the genetic mating system and identify patterns of paternity through genotyping individuals at 10 microsatellite loci. Additionally, we investigated the importance of body mass and site residency as strategies in securing paternity. Twelve of the 17 pouch young sampled were assigned paternity with confidence to five males. Multiple pouch young were sampled from two long-term resident females, one of which had 10 pouch young sired by multiple partners, with some repeat paternity, while the other had three young sired by one male, suggesting that the mating system is not entirely promiscuous. Sires were recorded on site for significantly longer periods than non-sires but were not significantly larger than non-sires at conception. This suggests that sires employ strategies other than direct competition, such as scramble competition, to secure paternity in P. tridactylus. A population of long-nosed potoroos was monitored for five years. Twelve pouch young were assigned paternity. One female produced young with multiple males, and another with a single male, suggesting that the mating system is not entirely promiscuous. Sires were on site for significantly longer than non-sires but were not significantly larger. [ABSTRACT FROM AUTHOR]

Abstract: The three extant potoroo species of the marsupial genus Potorous –Potorous tridactylus, P. longipes and P. gilbertii – are all of conservation concern due to introduced predators and habitat loss associated with the European settlement of Australia. Robust phylogenies can be useful to inform conservation management, but past phylogenetic studies on potoroos have been unable to fully resolve relationships within the genus. Here, a multi-locus approach was employed, using three mitochondrial DNA (mtDNA): NADH dehydrogenase subunit 2, cytochrome c oxidase subunit 1 and 12S rRNA and four nuclear DNA (nuDNA) gene regions: breast and ovarian cancer susceptibility gene, recombination activating gene-1, apolipoprotein B and omega globin. This was coupled with widespread geographic sampling of the broadly distributed P. tridactylus, to investigate the phylogenetic relationships within this genus. Analyses of the mtDNA identified five distinct and highly divergent lineages including, P. longipes, P. gilbertii and three distinct lineages within P. tridactylus (northern mainland, southern mainland and Tasmanian). P. tridactylus was paraphyletic with the P. gilbertii lineage, suggesting that cryptic taxa may exist within P. tridactylus. NuDNA sequences lacked the resolution of mtDNA. Although they resolved the three currently recognised species, they were unable to differentiate lineages within P. tridactylus. Current management of P. tridactylus as two sub-species (mainland and Tasmania) does not recognise the full scope of genetic diversity within this species, especially that of the mainland populations. Until data from more informative nuDNA markers are available, we recommend this species be managed as the following three subspecies: Potorous tridactylus tridactylus (southern Queensland and northern New South Wales); Potorous tridactylus trisulcatus (southern New South Wales and Victoria) Potorous tridactylus apicalis (Tasmania). Molecular dating estimated that divergences within Potorous occurred in the late Miocene through to the early Pliocene. [Copyright &y& Elsevier]