Overcoming barriers to active interventions for genetic diversity

Stowell, Sierra M. Love; Pinzone, Cheryl A.; Martin, Andrew P.

doi:10.1007/s10531-017-1330-z

Cited by 43 publications

(65 citation statements)

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“…Selecting appropriate sources of admixture requires simultaneous consideration of the timescale of population differentiation and the risks of inbreeding versus outbreeding depression and loss of local adaptation (Frankham et al., ; Love Stowell et al., ; Weeks et al., , ). Long‐term divergence implies that reproductive isolation may have evolved through adaptive differentiation and/or drift; hence, admixture between regions showing histories of long‐term divergence and/or local adaptation should be undertaken with caution (Frankham et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…In some cases, nearby (presumably similarly adapted) source populations do not exist, so there may be no option but to source individuals for translocation from a more strongly divergent population (Love Stowell et al., ; Weeks et al., ), as suggested for threatened southern pygmy perch from the MDB based on genotype–environment association analyses (Brauer, Hammer, & Beheregaray, ). In the Lachlan catchment (MDB), two sampled Macquarie perch populations are recent derivatives from the same source (and are connected by unidirectional gene flow from the Abercrombie to Lachlan; Faulks et al., ); thus, little genetic rescue/restoration effect would be expected from their admixture (Frankham, ).…”

Section: Discussionmentioning

confidence: 99%

“…Another common argument against genetic augmentation is that gene flow between divergent populations may “swamp” local adaptation and distinctiveness, or contribute to outbreeding depression (Frankham et al., ; Le Cam, Perrier, Besnard, Bernatchez, & Evanno, ; Love Stowell et al., ). Such concerns frequently lead to recommendations to maintain isolation of differentiated populations, but without appropriate assessment of the risks and benefits of gene flow (Farrington, Lintermans, & Ebner, ; Frankham et al., ; Roberts, Baker, & Perrin, ).…”

Section: Introductionmentioning

confidence: 99%

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Severe consequences of habitat fragmentation on genetic diversity of an endangered Australian freshwater fish: A call for assisted gene flow

Pavlova

Beheregaray

Coleman

et al. 2017

Evolutionary Applications

141

134

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Genetic diversity underpins the ability of populations to persist and adapt to environmental changes. Substantial empirical data show that genetic diversity rapidly deteriorates in small and isolated populations due to genetic drift, leading to reduction in adaptive potential and fitness and increase in inbreeding. Assisted gene flow (e.g. via translocations) can reverse these trends, but lack of data on fitness loss and fear of impairing population “uniqueness” often prevents managers from acting. Here, we use population genetic and riverscape genetic analyses and simulations to explore the consequences of extensive habitat loss and fragmentation on population genetic diversity and future population trajectories of an endangered Australian freshwater fish, Macquarie perch Macquaria australasica. Using guidelines to assess the risk of outbreeding depression under admixture, we develop recommendations for population management, identify populations requiring genetic rescue and/or genetic restoration and potential donor sources. We found that most remaining populations of Macquarie perch have low genetic diversity, and effective population sizes below the threshold required to retain adaptive potential. Our simulations showed that under management inaction, smaller populations of Macquarie perch will face inbreeding depression within a few decades, but regular small‐scale translocations will rapidly rescue populations from inbreeding depression and increase adaptive potential through genetic restoration. Despite the lack of data on fitness loss, based on our genetic data for Macquarie perch populations, simulations and empirical results from other systems, we recommend regular and frequent translocations among remnant populations within catchments. These translocations will emulate the effect of historical gene flow and improve population persistence through decrease in demographic and genetic stochasticity. Increasing population genetic connectivity within each catchment will help to maintain large effective population sizes and maximize species adaptive potential. The approach proposed here could be readily applicable to genetic management of other threatened species to improve their adaptive potential.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Severe consequences of habitat fragmentation on genetic diversity of an endangered Australian freshwater fish: A call for assisted gene flow

Pavlova

Beheregaray

Coleman

et al. 2017

Evolutionary Applications

141

134

View full text Add to dashboard Cite

show abstract

“…Another option is to incentivise or mandate wildlife ranchers to register populations of species where the taxonomic integrity of that species has been preserved (based on management history and genetic tests) and to tightly control introductions into and translocations from these populations. In contrast, some may argue that actions such as deliberate admixture by introducing individuals from related subspecies may be necessary to recover population fitness even though the taxonomic integrity of a species may be temporarily disrupted (Stowell et al 2017). This issue of genetic rescue to prevent species from extinction is debated in the literature (Frankham 2015;Stowell et al 2017).…”

Section: Decisionsmentioning

confidence: 99%

“…In contrast, some may argue that actions such as deliberate admixture by introducing individuals from related subspecies may be necessary to recover population fitness even though the taxonomic integrity of a species may be temporarily disrupted (Stowell et al 2017). This issue of genetic rescue to prevent species from extinction is debated in the literature (Frankham 2015;Stowell et al 2017). However, here we refer to the issue of deliberate subspecies admixture where there is no threat of extinction or reduced population fitness to either of the subspecies.…”

Section: Decisionsmentioning

confidence: 99%

‘Intentional Genetic Manipulation’ as a conservation threat

Russo

Hoban

Bloomer

et al. 2018

Conservation Genet Resour

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Wildlife ranching including the hunting, collection, sales and husbandry of wild animals in captivity, is practised worldwide and is advocated as an approach towards the conservation of wild species. While many authors have explored the biological impacts of intensive wild population management, primarily with respect to disease transmission (especially in ungulates and fish), the evolutionary and demographic effects of wildlife ranching have been examined less intensively. We discuss this issue through the case of intensive wildlife management in southern Africa. The genetic consequences of this global practice, with an emphasis on Africa, were addressed by a motion passed at the 2016 IUCN World Congress-'Management and regulation of intensive breeding and genetic manipulation of large mammals for commercial purposes'. Here, we highlight concerns regarding intensive breeding programs used to discover, enhance and propagate unusual physical traits, hereafter referred to as 'Intentional Genetic Manipulation'. We highlight how 'Intentional Genetic Manipulation' potentially threatens the viability of native species and ecosystems, via genetic erosion, inbreeding, hybridisation and unregulated translocation. Finally, we discuss the need for better policies in southern Africa and globally, regarding 'Intentional Genetic Manipulation', and the identification of key knowledge gaps.

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Politics and pride: Maintaining genetic novelty may be detrimental for the conservation of Formosa landlocked salmon Oncorhynchus formosanus

Burridge

2019

Aquatic Conservation

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1. Populations of conservation concern are often rare, restricted in range, and isolated from other populations. This can manifest in low genetic diversity, which reduces the ability of a population to respond to changes in the environment, and in higher levels of inbreeding, which reduce individual fitness. Isolated populations, however, often harbour genetic and phenotypic novelty, which can elicit a strong community sentiment to maintain these populations.2. Genetic rescuethe introduction of genetic variation to improve fitnessoffers potential benefits for isolated and threatened populations, but has associated risks, including a perceived loss in identity if that population is geographically, genetically, and culturally significant. Here, the potential benefits and risks of genetic rescue for isolated freshwater populations are discussed, using the Formosa salmon as an exemplar.3. Formosa landlocked salmon, a member of the masu salmon complex (Oncorhynchus masou sensu lato), is the southernmost naturally distributed salmonid in the world, occupying a single stream at high elevation in Taiwan. Listed as Critically Endangered, it exhibits continuing low abundance (<5000 individuals). Although Formosa salmon can be genetically distinguished from other masu salmon, its genetic variation is extremely low and genetic factors may now critically affect fitness.4. There appears to be clear merit for the genetic rescue of Formosa salmon, and test crosses involving other landlocked masu salmon are urgently required. If these test crosses yield individuals of high fitness, guidelines for introductions into the wild are provided. In addition, subpopulations above and below artificial instream barriers to movement require connection via the direct exchange of individuals to minimize any further losses of genetic variation. Insurance populations with independent risk probabilities to the existing population should also be constructed, with continuing connectivity among populations through the direct exchange of individuals.

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Overcoming barriers to active interventions for genetic diversity

Cited by 43 publications

References 65 publications

Severe consequences of habitat fragmentation on genetic diversity of an endangered Australian freshwater fish: A call for assisted gene flow

Severe consequences of habitat fragmentation on genetic diversity of an endangered Australian freshwater fish: A call for assisted gene flow

‘Intentional Genetic Manipulation’ as a conservation threat

Politics and pride: Maintaining genetic novelty may be detrimental for the conservation of Formosa landlocked salmon Oncorhynchus formosanus

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