2016-12-23T18:52:10

No abstract

Identification of the geographic extent of population boundaries, the distribution of genetic lineages, and the amount of genetic exchange among breeding groups is needed for effective conservation of vulnerable marine migratory species. This is particularly true of the flatback turtle (Natator depressus), which only breeds in Australia but has extensive migrations that can include international waters. This study investigated the phylogeography and genetic structure among 17 flatback turtle rookeries across their range by sequencing an 810 bp portion of the mitochondrial DNA in 889 samples and genotyping 10 microsatellite loci in 598 samples. There was low phylogenetic divergence among haplotypes and evidence of recent population expansion, likely in the late Pleistocene. A predominant haplotype was found across all rookeries, but other haplotype groups were regionally specific. In general, there was agreement in patterns of genetic differentiation in the mitochondrial DNA and microsatellite data, and in some pairwise comparisons a higher mutation rate of microsatellites provided stronger evidence of differentiation. These results suggest natal philopatry operates in the choice of breeding locations for males as well as females. Evidence of genetic connectivity among neighbouring rookeries led to the identification of seven genetic stocks. Geographic boundaries of rookeries used by genetic stocks varied widely (160–1,300 km), highlighting a need for field studies to better understand movement patterns. Hierarchical analysis of molecular variance identified significant genetic differentiation based upon genetic stock, nesting phenology (summer vs. winter nesters), and a west–east discontinuity across Torres Strait. A pattern of isolation by distance was identified, which was most strongly observed in the microsatellite data. In combination with tagging and telemetry studies, these results will allow better quantification of stock‐specific threats along migratory routes and in foraging habitats. Implications of climate change will be stock specific and may depend upon the extent of genetic connectivity between neighbouring stocks.

Effective management decisions about the conservation of threatened species often rely on good information about their biology and life-history traits. Nearly half of all turtle species face extinction in the wild through worldwide rapid declines in species abundance and habitat loss. The vulnerable western sawshelled turtle, Myuchelys bellii, from eastern Australia is one such species under threat and for which fundamental information is lacking. The three known populations of M. bellii in the Murray–Darling Basin from the Namoi, Gwydir and Border Rivers catchments were studied over a period of nearly eight years. From capture–mark–recapture data, we studied M. bellii’s sexual maturity and reproduction, compared age of individuals using growth rates derived from annuli and growth increment data and calculated a population estimate for the Queensland population. For the first time this study has quantified the life-history traits of M. bellii including having delayed age at first breeding, with males taking nearly 10 years to mature and females approaching 20 years (from growth increment data), low reproductive effort (14.3 eggs per adult female; 78% of females breeding in any one year) and high survivorship with a predicted lifespan of over 40 years. Of particular management concern for M. bellii is the long-term conservation of the small isolated Queensland population (<400 individuals). The extensive dataset provides a baseline for future investigations and management actions required to improve the conservation outcomes for this threatened turtle.

Boiga irregularis, a snake native to Australasia, is a biologically invasive species that has become established on Guam and threatens to spread to other Pacific Islands. In eastern Queensland, we found that the snake breeds seasonally and gonadal development of males and females is temporally dissociated in time. Although the period of mating in this snake is not known, these data suggest that obligatory sperm storage in the reproductive tract occurs during the reproductive cycle. Such sperm storage may partially explain the success of this species as a biological invader.