Tracking the Long-Term Decline and Recovery of an Isolated Population

Westemeier, Ronald L.; Brawn, Jeffrey D.; Simpson, Scott A.; Esker, Terry L.; Jansen, Roger W.; Walk, Jeffery W.; Kershner, Eric L.; Bouzat, Juan L.; Paige, Ken N.

doi:10.1126/science.282.5394.1695

Cited by 606 publications

(497 citation statements)

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“…Although there are quite a number of risks connected with genetic rescue (Tallmon et al 2004;Edmands 2007;Hedrick and Fredrickson 2010) including the ones discussed here, genetic rescue has proven to be a successful method to increase the fitness of genetically eroded populations and to improve their persistence (Hedrick 1995;Westemeier et al 1998;Madsen et al 1999;Willi et al 2007;Bouzat et al 2009;Hedrick and Fredrickson 2010). Thus if populations decline in numbers partly due to genetic problems and because of this have a high probability of going extinct in the near future, genetic rescue offers a viable management option, notwithstanding the risks connected to it.…”

Section: Inferences For Conservation Managementmentioning

confidence: 95%

“…frequency dependent selection for rare S-alleles in plants (Leducq et al 2010)). This concept of genetic rescue is now considered to be a realistic management option to counteract the increased extinction risk from genetic erosion (for reviews see Tallmon et al 2004;Hedrick 2005;Edmands 2007), and has been shown to be very effective in a number of cases (Hedrick 1995;Westemeier et al 1998;Madsen et al 1999;Willi et al 2007;Bouzat et al 2009;Hedrick and Fredrickson 2010).…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of genetic rescue in inbred Drosophila melanogaster populations

et al. 2010

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Genetic rescue has been proposed as a management strategy to improve the fitness of genetically eroded populations by alleviating inbreeding depression. We studied the dynamics of genetic rescue in inbred populations of Drosophila. Using balancer chromosomes, we show that the force of heterosis that accompanies genetic rescue is large and allows even a recessive lethal to increase substantially in frequency in the rescued populations, particularly at stress temperatures. This indicates that deleterious alleles present in the immigrants can increase significantly in frequency in the recipient population when they are in linkage disequilibrium with genes responsible for the heterosis. In a second experiment we rescued eight inbred Drosophila populations with immigrants from two other inbred populations and observe: (i) there is a significant increase in viability both 5 and 10 generations after the rescue event, showing that the increase in fitness is not transient but persists long-term. (ii) The lower the fitness of the recipient population the larger the fitness increase. (iii) The increase in fitness depends significantly on the origin of the rescuers. The immigrants used were fixed for a conditional lethal that was mildly deleterious at 25°C but lethal at 29°C. By comparing fitness at 25°C (the temperature during the rescue experiment) and 29°C, we show that the lethal allele reached significant frequencies in most rescued populations, which upon renewed inbreeding became fixed in part of the inbred lines. In conclusion, in addition to the fitness increase genetic rescue can easily result in a substantial increase in the frequency of mildly deleterious alleles carried by the immigrants. This can endanger the rescued population greatly when it undergoes recurrent inbreeding. However, using a sufficient number of immigrants and to accompany the rescue event with the right demographic measures will overcome this problem. As such, genetic rescue still is a viable option to manage genetically eroded populations.

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Section: Inferences For Conservation Managementmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Dynamics of genetic rescue in inbred Drosophila melanogaster populations

et al. 2010

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“…Population losses and the concomitant loss of genetic variation associated with these slow but sustained pressures over multiple generations have been linked to inbreeding depression and negative impacts on adaptability and fitness. Assessing the genetic effects of gradual declines is crucial to the management of shorebirds and other wildlife populations (Westemeier et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Museum collections reveal that Buff-breasted Sandpipers (Calidris subruficollis) maintained mtDNA variability despite large population declines during the past 135 years

et al. 2014

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A principal goal of conservation efforts for threatened and endangered taxa is maintenance of genetic diversity. Modern and historic processes that limit population size can contribute to a loss of genetic variation that can reduce future adaptability of a species. Buff-breasted Sandpipers (Calidris subruficollis) are a Neotropical migratory shorebird that experienced rapid, large-scale declines in population numbers (population bottleneck) due to intensive market hunting at the turn of the 20th century. Market hunting ended shortly after the passage of the Migratory Bird Treaty Act in 1918, but subsequent population losses have occurred due to continued anthropogenic disturbances throughout the species' migratory range. To assess the impact of population declines on the genetic variation of Buff-breasted Sandpipers, we surveyed two mitochondrial DNA (mtDNA) markers, the control region and cytochrome b, from 209 museum specimens collected between 1874 and 1983 and 460 modern samples collected between 1993 and 2009. Measures of mtDNA variation did not change significantly among individuals sampled before and after the ban on market hunting, nor among four temporal groups (Pre-Act, Early Post-Act, Late Post-Act, and Modern; trend analysis: v 2 = 0.171, P = 0.679). Similarly, we did not observe loss of common haplotypes, implying that there was no substantial reduction in unique matrilineal units during our 135-year study period. Using Bayesian Skyline reconstruction of temporal changes in effective population size of females (N ef ), we concluded that N ef has been stable for the past century. Results of resampling suggest that diversity estimators can be imprecise and we emphasize the importance of a wellrounded analytical approach to addressing conservation genetic hypotheses. Considering all of the evidence it appears that genetic variation and N ef were stable despite the pressures of market hunting early in the 20th century and habitat loss and degradation in the latter half of the 20th century. Conservation efforts should continue to focus on maintaining the population size of Buff-breasted Sandpipers to avoid reaching a threshold where genetic variability is lost.

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“…The decline in genetic diversity in populations R1-R3 as observed in this study is an important warning, as the reintroductions in these areas were performed by releasing individuals from the NL breeding line only, having already a lower genetic diversity compared with other breeding lines. Even a small decline in genetic diversity may affect population persistence of R1-R3 in the long term as a lowered genetic diversity is associated with endangered and failing populations (Madsen et al 1999;Westemeier et al 1998;Carlson et al 2014;Whiteley et al 2015), although habitat quality and habitat management often plays a more dominant role in population persistence (Spielman et al 2004;Bouzat et al 2009;La Haye et al 2014).The populations of R4-R5 were established by releasing individuals of two breeding lines (NL and G/NL). This strategy was followed to maximize levels of genetic diversity in the new populations.…”

mentioning

confidence: 99%

“…Despite these disadvantages, reintroduction has become an important and frequently applied strategy for the conservation of a broad variety of mammals, ranging from small mammals (Ottewell et al 2014;McCleery et al 2014) till large carnivores (Hayward et al 2007). Unfortunately, the overall success of reintroductions is low (Fischer and Lindenmayer 2000;Tenhumberg et al 2004;Armstrong and Seddon 2008) and several authors (Robert 2009;Weeks et al 2011) have stressed the need of giving attention to the genetic adaptive potential of reintroduced populations (Carlson et al 2014;Jamieson 2015) as a low genetic adaptive potential may hamper a successful recovery of the species (Madsen et al 1999;Westemeier et al 1998;Carlson et al 2014;Whiteley et al 2015). By implementing a systematic genetic monitoring, which we define as 'quantifying temporal changes in population genetic metrics' (following Schwartz et al 2007), when starting a reintroduction project, very important information of both the genetic status of the population and population demographic parameters can be gained, while the results of such a monitoring can be used to optimize conservation actions (Schwartz et al 2007).…”

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confidence: 99%

Genetic monitoring to evaluate reintroduction attempts of a highly endangered rodent

Haye

Reiners

Raedts³

et al. 2017

Conserv Genet

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a systematic reintroduction scheme including consecutive supplementations made it possible to infer success of reintroduction, supplementation and following admixture of populations. An initial loss of genetic diversity could be detected in some of the reintroduced populations, but it could be shown that due to following supplementation of populations, genetic diversity and also effective population size in the wild stabilized or even increased. Multivariate (DAPC) and Bayesian inference (STRUCTURE) revealed admixture of supplemented individuals with wild-born individuals. Although population size estimates differed strongly between populations, a link between census size, breeding lines, effective population size and genetic diversity could not be proven. This study highlights that genetic monitoring is not only descriptive but also reveals detailed information on reintroduction success, admixture and population development. We recommend that genetic monitoring should be a basic element of reintroductions and should be used to optimize reintroduction attempts.Keywords Captive breeding · Common hamster · Founder effect · Admixture · Genetic variation · Effective and census population size IntroductionThe current global biodiversity crisis affects many groups of species, including a wide range of mammalian species (Di Marco et al. 2014). A global conservation strategy for mammalian species is therefore urgently needed (Rondinini et al. 2011), but the success of conservation strategies is uncertain as many factors influence the result of conservation projects (Crees et al. 2016). The ultimate strategy to prevent extinction or to increase population Abstract The ultimate strategy to prevent species extinction is captive breeding followed by reintroduction of individuals into the wild. Unfortunately, overall success of reintroductions is poor and in most cases conservation breeding is applied for species where individual numbers, population numbers and genetic diversity is strongly reduced. In addition, reintroductions inevitably result in small populations with poor genetic status. Systematic demographic and genetic monitoring is needed to optimize conservation actions. Here we show how genetic monitoring was useful and informative in a reintroduction project for the highly endangered Common hamster (Cricetus cricetus) in the Netherlands and Belgium. Using well defined breeding lines of original relict populations combined with M. J. J. La Haye and T. E. Reiners have contributed equally to this work. numbers of mammalian species is captive breeding followed by reintroduction of captive-bred individuals into the wild (IUCN 2013). However, captive breeding and reintroduction have severe disadvantages. Reintroductions can be difficult and expensive (Tenhumberg et al. 2004), and the release of captive-bred individuals is often accompanied by high initial losses of released individuals (Villemey et al. 2013;McCleery et al. 2014). Moreover, captive breeding is mostly started in species with already highly threatened popu...

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Tracking the Long-Term Decline and Recovery of an Isolated Population

Cited by 606 publications

References 17 publications

Dynamics of genetic rescue in inbred Drosophila melanogaster populations

Dynamics of genetic rescue in inbred Drosophila melanogaster populations

Museum collections reveal that Buff-breasted Sandpipers (Calidris subruficollis) maintained mtDNA variability despite large population declines during the past 135 years

Genetic monitoring to evaluate reintroduction attempts of a highly endangered rodent

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