Establishment, persistence and the importance of longitudinal monitoring in multi-source reintroductions

Incorporating genetic data into conservation programmes improves management outcomes, but the impact of different sample grouping methods on genetic diversity analyses is poorly understood. To this end, the multi-source reintroduction of the eastern bettong Bettongia gaimardi was used as a long-term case study to investigate how sampling regimes may affect common genetic metrics and hence management decisions. The dataset comprised 5307 SNPs sequenced across 263 individuals. Samples included 45 founders from five genetically distinct Tasmanian source regions, and 218 of their descendants captured during annual monitoring at Mulligan’s Flat Woodland Sanctuary (121 samples across eight generations) and Tidbinbilla Nature Reserve (97 samples across nine generations). The most management-informative sampling regime was found to be generational cohorts, providing detailed long-term trends in genetic diversity. When these generation-specific trends were not investigated, recent changes in population genetics were masked, and it became apparent that management recommendations would be less appropriate. The results also illuminated the importance of considering establishment and persistence as separate phases of a multi-source reintroduction. The establishment phase (useful for informing early adaptive management) should consist of no less than two generations and continue until admixture is achieved (admixture defined here as >80% of individuals possessing >60% of source genotypes, with no one source composing >70% of >20% individuals’ genotype) is achieved. This ensures that the persistence phase analyses of population trends remain minimally biased. Based on this case study, we recommend that emphasis be given to the value of generationally specific analyses, and that conservation programmes collect DNA samples throughout the establishment and persistence phases and avoid collecting genetic samples only when the analysis is imminent. We also recommend that population genetic analyses for multi-source reintroductions consider whether admixture has been achieved when calculating descriptive genetic metrics

Restricted gene flow in the endangered Capricorn Yellow Chat Epthianura crocea macgregori: Consequences for conservation management

Summary The Yellow Chat Epthianura crocea is comprised of three disjunct subspecies. Subspecies E. c. macgregori (Capricorn Yellow Chat) is listed as Critically Endangered under the EPBC Act and has a distribution that also appears to be disjunct, with a limited geographic area of less than 7,000 ha. Some populations are threatened by rapid industrial development, and it is important for conservation of the subspecies to determine the extent to which the putative populations are connected. We used 14 microsatellite markers to measure genetic diversity and to determine the extent of gene flow between two disjunct populations at the northern and southern extremes of the subspecies' range. No significant differences in genetic diversity (number of alleles and heterozygosity) were observed, but clear population structuring was apparent, with obvious differentiation between the northern and southern populations. The most likely explanation for reduced gene flow between the two populations is either the development of a geographic barrier as a consequence of shrinkage of the marine plains associated with the rise in sea levels following the last glacial maxima, or reduced connectivity across the largely unsuitable pasture and forest habitat that now separates the two populations, exacerbated by declining population size and fewer potential emigrants. Regardless of the mechanism, restricted gene flow between these two populations has important consequences for their ongoing conservation. The relative isolation of the smaller southern groups (the Fitzroy River delta and Curtis Island) from the much larger northern group (both sides of the Broad Sound) makes the southern population more vulnerable to local extinction. Conservation efforts should focus on nature refuge agreements with land owners agreeing to maintain favourable grazing management practices in perpetuity, particularly in the northern area where most chats occur. Supplemental exchanges of individuals from northern and southern populations should be explored as a way of increasing genetic diversity and reducing inbreeding. Copyright © BirdLife International 2017

Trends in animal translocation research

Translocations are an important conservation tool that enable the restoration of species and their ecological functions. They are particularly important during the current environmental crisis. We used a combination of text-analysis tools to track the history and evolution of the peer-reviewed scientific literature on animal translocation science. We compared this corpus with research showcased in the IUCNs Global Conservation Translocation Perspectives, a curated collection of non-peer-reviewed reintroduction case studies. We show that the peer-reviewed literature, in its infancy, was dominated by charismatic species. It then grew in two classical threads: management of the species of concern and management of the environment of the species. The peer-reviewed literature exhibits a bias towards large charismatic mammals, and while these data are invaluable, expansion to under-represented groups such as insects and reptiles will be critical to combating biodiversity loss across taxonomic groups. These biases were similar in the Translocation Perspectives, but with some subtle differences. To ensure translocation science can address global issues, we need to overcome barriers that restrict this research to a limited number of countries