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Conservation Genetics
Journal Prestige (SJR): 0.924
Citation Impact (citeScore): 2
Number of Followers: 22  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1572-9737 - ISSN (Online) 1566-0621
Published by Springer-Verlag Homepage  [2467 journals]
  • High genetic diversity in American chestnut (Castanea dentata) despite a
           century of decline

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      Abstract: Abstract Knowledge of the magnitude and geographic patterns of genetic diversity is instrumental for recovery of endangered tree species whose persistence is limited by genetic variation. One such species is American chestnut (Castanea dentata), which has experienced a dramatic reduction in population size in North America in association with the spread of the parasitic fungus, Cryphonectria parasitica, causing chestnut blight. To examine the impact of the bottleneck and role of genetic diversity on population dynamics and recovery, we conducted a population genetic assessment of native American chestnut populations in the understudied northern range in Canada and along a transect towards the center of the U.S. range. Leaf tissue from 13 natural populations in Canada (N = 7) and northern U.S. (N = 6) were genetically characterized using 16 microsatellite loci and compared to a sample of reference Castanea species. Genetic diversity and population structure were assessed within and among populations to determine population connectivity and the presence of admixture with other Castanea spp. Populations throughout the range displayed high genetic diversity and significant inbreeding, with no significant difference in diversity between those at the center and edge of the range. We found evidence of infrequent interspecific hybridization in some Canadian populations but no relationship between admixture and tree health, assessed in a previous demographic survey. Unexpectedly, Canadian populations clustered separately from U.S. populations. American chestnut appears to have retained substantial genetic diversity following the population bottleneck, which is at odds with the limited incidence of blight resistance/tolerance in extant populations.
      PubDate: 2023-02-01
       
  • Reproductive biology and population structure of the endangered shrub
           Grevillea bedggoodiana (Proteaceae)

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      Abstract: Abstract Narrowly endemic species are particularly vulnerable to catastrophic events. Compared to widespread species, they may also be less capable of adapting to shifts in environmental pressures as a result of specialisation on a narrow range of local condition and limited ability to disperse. However, life-history traits, such as preferential outcrossing and high fecundity can maintain genetic diversity and evolutionary potential, and boost species resilience. The endangered Grevillea bedggoodiana (Enfield Grevillea) is an understorey shrub restricted to an area of ca. 150 km2 in south-eastern Australia with a legacy of large-scale anthropogenic disturbance. Prior to this study little was known about its biology and population structure. Here, its breeding system was assessed through a controlled pollination experiment at one of its central populations, and eight populations were sampled for genetic analysis with microsatellite markers. The species was found to be preferentially outcrossing, with no evidence of pollination limitation. In most populations, allelic richness, observed heterozygosity and gene diversity were high (Ar: 3.8–6.3; Ho: 0.45–0.65, He: 0.60 − 0.75). However, the inbreeding coefficients were significant in at least four populations, ranging from Fi -0.061 to 0.259 despite high outcrossing rates. Estimated reproductive rates varied among sampled populations but were independent of gene diversity and inbreeding. Despite its small geographic range, the species’ populations showed moderate differentiation (AMOVA: FST = 0.123), which was largely attributable to isolation by distance. We interpret these results as suggesting that G. bedggoodiana is reproductively healthy and has maintained high levels of genetic diversity despite recent disturbance.
      PubDate: 2023-02-01
       
  • The genetic structure and connectivity in two sympatric rodent species
           with different life histories are similarly affected by land use
           disturbances

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      Abstract: Abstract The negative impact of habitat fragmentation due to human activities may be different in different species that co-exist in the same area, with consequences on the development of environmental protection plans. Here we aim at understanding the effects produced by different natural and anthropic landscape features on gene flow patterns in two sympatric species with different specializations, one generalist and one specialist, sampled in the same locations. We collected and genotyped 194 wood mice (generalist species) and 199 bank voles (specialist species) from 15 woodlands in a fragmented landscape characterized by different potential barriers to dispersal. Genetic variation and structure were analyzed in the two species, respectively. Effective migration surfaces, isolation-by-resistance (IBR) analysis, and regression with randomization were used to investigate isolation-by-distance (IBD) and the relative importance of land cover elements on gene flow. We observed similar patterns of heterozygosity and IBD for both species, but the bank vole showed higher genetic differences among geographic areas. The IBR analysis suggests that (i) connectivity is reduced in both species by urban areas but more strongly in the specialist bank vole; (ii) cultivated areas act as dispersal corridors in both species; (iii) woodlands appear to be an important factor in increasing connectivity in the bank vole, and less so in the wood mouse. The difference in dispersal abilities between a generalist and specialist species was reflected in the difference in genetic structure, despite extensive habitat changes due to human activities. The negative effects of fragmentation due to the process of urbanization were, at least partially, mitigated by another human product, i.e., cultivated terrains subdivided by hedgerows, and this was true for both species.
      PubDate: 2023-02-01
       
  • Not all is black and white: phylogeography and population genetics of the
           endemic blackbuck (Antilope cervicapra)

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      Abstract: Abstract Genetic diversity of organisms is an indicator of their long-term survival and can potentially be shaped by the extent of geneflow between populations. Geographical features and anthropogenic interferences can both obstruct and also facilitate animal movement, directly or indirectly. Such patterns have not been extensively studied across grasslands in the Indian subcontinent which is a mosaic of both natural and man-made topography. This study looks at genetic variation in an endemic ungulate, the Antilope cervicapra or blackbuck, throughout its distribution range. Using mitochondrial and nuclear (microsatellite) information, we find that different markers shed light on different aspects of their evolutionary history. Absence of robust geographical clustering in mitochondrial DNA indicate recent isolation in these populations, while lack of shared haplotypes between sampling locations suggests female philopatry. Nuclear data shows the presence of three genetic clusters in this species, pertaining to the Northern, Southern and Eastern regions of India. Our study also shows that an ancestral stock separated into two groups that gave rise to the North and South clusters and the East population was derived from the South at a later time period. Both microsatellite and mitochondrial data indicate that the population from the Eastern part of India is genetically distinct and the species as a whole shows signatures of having undergone recent genetic expansion. In spite of immense losses in grassland habitats across India, blackbucks seem to have well-adapted to human altered landscapes and their numbers are beginning to show an upward trend.
      PubDate: 2023-02-01
       
  • Capturing conservation in the post-genomics era: a book review of
           ā€œConservation and the Genomics of Populations.ā€

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      Abstract: Abstract Conservation genetics is a relatively new discipline, and yet has rapidly evolved in the last decade with massive advances in sequencing technologies. Here, we review the newest edition of an influential textbook in the field, “Conservation and the Genomics of Populations”, which seeks to bridge the transition from population genetics to genomics and its application to conservation management. This textbook—complete with 24 chapters (one completely new), 25 guest boxes, and two new authors over the previous edition—navigates the rich and sometimes complex history of conservation and population genetics, while also providing a comprehensive catalog of how genomics broadens our understanding of diversity in a changing world. Despite some sections requiring an advanced understanding of population genetic theory, we foresee this text being used as a reference for conservation geneticists and for teaching upper level undergraduate or graduate students. While we anticipate the field of conservation genetics will continue to rapidly advance with new technologies, this textbook provides a strong foundation of population genetics, while also celebrating the new horizon of genomics for conservation management.
      PubDate: 2023-02-01
       
  • Genetic dynamics of a 11-year ex situ managed Itasenpara bitterling
           population

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      Abstract: Abstract EX situ conservation management is an effective method that conserves endangered species that are on the decline owing to anthropogenic alteration of natural habitats. This entails the management of a captive population while maintaining its genetic variability and preventing its adaptation to the captive environment. However, implementation of such efforts is largely limited to experimental animals and zoo-managed animals with pedigree information. In this study, ex situ management of endangered Itasenpara bitterling (Acheilognathus longipinnis) was conducted, while practicing recommended conservation procedures, for the purpose of conserving this species. In this 11 year long study, we conducted multi-locus microsatellite DNA analyses to evaluate the genetic dynamics of an ex situ captive population of A. longipinnis, as well as the wild A. longipinnis population of the Kiso River. Genetic diversity generally varied between yearly cohorts in each of the captive sub-populations, and some showed a stable increasing trend with generations. When all sub-populations were considered as one population, genetic diversity was maintained at a high value, while effective population size generally reached target values, thereby preventing inbreeding. These results were achieved by maintaining multiple captive sub-populations and exchanging individuals between them. Simultaneously, the introduction of additional individuals from the wild population produced genetic variability in the captive population. These fluctuating patterns of genetic diversity in the captive A. longipinnis population were desirable compared to previously predicted values. Consequently, these findings show that the current ex situ conservation program is suitable for maintaining the genetic composition of the captive population of A. longipinnis.
      PubDate: 2023-02-01
       
  • Inferring inter-colony movement within metapopulations of yellow-footed
           rock-wallabies using estimates of kinship

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      Abstract: Abstract Understanding the exchange of individuals between wildlife populations, particularly those with naturally fragmented habitats, is important for the effective management of these species. This is of particular consequence when the species is of conservation concern, and isolated populations may be lost due to pressures from predation or competition, or catastrophic events such as wildfire. Here we demonstrate the use kinship and population structure analysis to show potential recent movement between colonies in metapopulations of yellow-footed rock-wallaby (Petrogale xanthopus Gray 1854) at two sites in the Grey Range of Queensland, and at four sites in the Gawler Ranges of South Australia. These colonies are also compared to a single colony from the Flinders Ranges, a connected landscape of rock-wallaby habitat. Using reduced representation next-generation sequencing, we acquired and filtered a set of ~ 17,000 single-nucleotide polymorphisms to examine population genetic variation, structure and relationships within populations, and also identify putative migrants. Initial STRUCTURE analysis re-confirmed each population should be considered separately. Tests of population genetic variation identify several colonies appearing to be experiencing genetic erosion, also with low calculated effective population sizes (Ne = 4.5–36.6). Pairwise comparisons of individual relatedness (relatedness coeffiecients; r) implied several contemporary movement events between colonies within both the Gawler and Grey Ranges (r > 0.125), which was then affirmed with tests for putative first generation migrants. These results are of particular note in South Australia, where threat abatement (management of key predators and competitors) may facilitate dispersion. Additionally, in Queensland, colonies are separated by anthropogenic barriers: predator exclusion fencing designed to exclude dingoes (Canis familiaris) from grazing land, which may hinder dispersal. This work highlights the usefulness of population genetics to inform management outcomes in wildlife, in this case, highlighting the need for threatened species management at the landscape level.
      PubDate: 2023-01-27
       
  • Examining the spatiotemporal variation of genetic diversity and genetic
           rarity in the natural plant recolonization of human-altered areas

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      Abstract: Abstract The spatiotemporal genetic variation at early plant life stages may substantially affect the natural recolonization of human-altered areas, which is crucial to understand plant and habitat conservation. In animal-dispersed plants, dispersers’ behavior may critically drive the distribution of genetic variation. Here, we examine how genetic rarity is spatially and temporally structured in seedlings of a keystone pioneer palm (Chamaerops humilis) and how the variation of genetic rarity could ultimately affect plant recruitment. We intensively monitored the seed rain mediated by two medium-sized carnivores during two consecutive seasons in a Mediterranean human-altered area. We genotyped 143 out of 309 detected seedlings using 12 microsatellite markers. We found that seedlings emerging from carnivore-dispersed seeds showed moderate to high levels of genetic diversity and no evidence of inbreeding. We found inflated kinship among seedlings that emerged from seeds within a single carnivore fecal sample, but a dilution of such FSGS at larger spatial scales (e.g. latrine). Seedlings showed a significant genetic sub-structure and the sibling relationships varied depending on the spatial scale. Rare genotypes arrived slightly later throughout the dispersal season and tended to be spatially isolated. However, genetic rarity was not a significant predictor by itself which indicates that, at least, its influence on seedling survival was smaller than other spatiotemporal factors. Our results suggest strong C. humilis resilience to genetic bottlenecks due to human disturbances. We highlight the study of plant-animal interactions from a genetic perspective since it provides crucial information for plant conservation and the recovery of genetic plant resilience.
      PubDate: 2023-01-27
       
  • Whole genome re-sequencing uncovers significant population structure and
           low genetic diversity in the endangered clouded apollo (Parnasssius
           mnemosyne) in Sweden

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      Abstract: Abstract The clouded apollo (Parnassius mnemosyne) used to have a wide distribution in Fennoscandia. Recent population declines have, however, led to regional extinctions and in Sweden it is currently one of the most endangered butterflies, confined to three geographically separated metapopulations: Blekinge, Roslagen and Västernorrland. Especially the Blekinge population has declined dramatically and few imagines have been observed during recent census efforts (< 10 in some localities). The clouded apollo is subject to a species action plan which includes both habitat restorations and captive breeding to produce individuals for release and reintroductions. Here, we apply whole-genome resequencing of clouded apollo individuals collected in the three natural populations and the captive population in Sweden and apply population genomic approaches to get a better understanding of the genetic structure and levels of genetic diversity in the species. We find that the clouded apollo populations in the different geographic regions have similar, but comparatively low levels of genetic diversity and we find evidence for significant genetic differentiation between the northernmost population and the populations in southern Sweden. Additional analysis, including previously available mitochondrial data, unveil that a bi-directional re-colonization of Fennoscandia after the latest glacial maximum most likely is the explanation for the considerable differentiation between some Swedish populations. Finally, we find evidence for population sub-structure in one of the Swedish populations. The results provide insights into the genetic consequences of population size declines and fragmentation in general and provide important information for direct conservation actions for the clouded apollo in Sweden in particular.
      PubDate: 2023-01-21
       
  • Conservation genomics reveals fine-scale population structuring and recent
           declines in the Critically Endangered Australian Kuranda Treefrog

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      Abstract: Abstract The Kuranda Treefrog occurs in tropical north-east Australia and is listed as Critically Endangered due to its small distribution and population size, with observed declines due to drought and human-associated impacts to habitat. Field surveys identified marked population declines in the mid-2000s, culminating in very low abundance at most sites in 2005 and 2006, followed by limited recovery. Here, samples from before (2001–2004) and after (2007–2009) this decline were analysed using 7132 neutral genome-wide SNPs to assess genetic connectivity among breeding sites, genetic erosion, and effective population size. We found a high level of genetic connectivity among breeding sites, but also structuring between the population at the eastern end of the distribution (Jumrum Creek) versus all other sites. Despite finding no detectable sign of genetic erosion between the two times periods, we observed a marked decrease in effective population size (Ne), from 1720 individuals pre-decline to 818 post-decline. This mirrors the decline detected in the field census data, but the magnitude of the decline suggested by the genetic data is greater. We conclude that the current effective population size for the Kuranda Treefrog remains around 800 adults, split equally between Jumrum Creek and all other sites combined. The Jumrum Creek habitat requires formal protection. Connectivity among all other sites must be maintained and improved through continued replanting of rainforest, and it is imperative that impacts to stream flow and water quality are carefully managed to maintain or increase population sizes and prevent genetic erosion.
      PubDate: 2023-01-17
       
  • Genetic diversity goals and targets have improved, but remain insufficient
           for clear implementation of the post-2020 global biodiversity framework

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      Abstract: Abstract Genetic diversity among and within populations of all species is necessary for people and nature to survive and thrive in a changing world. Over the past three years, commitments for conserving genetic diversity have become more ambitious and specific under the Convention on Biological Diversity’s (CBD) draft post-2020 global biodiversity framework (GBF). This Perspective article comments on how goals and targets of the GBF have evolved, the improvements that are still needed, lessons learned from this process, and connections between goals and targets and the actions and reporting that will be needed to maintain, protect, manage and monitor genetic diversity. It is possible and necessary that the GBF strives to maintain genetic diversity within and among populations of all species, to restore genetic connectivity, and to develop national genetic conservation strategies, and to report on these using proposed, feasible indicators.
      PubDate: 2023-01-16
       
  • Genetic diversity and connectivity of moose (Alces americanus americanus)
           in eastern North America

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      Abstract: Abstract Genetic diversity is critical to a population’s ability to overcome gradual environment change. Large-bodied wildlife existing in regions with relatively high human population density are vulnerable to isolation-induced genetic drift, population bottlenecks, and loss of genetic diversity. Moose (Alces americanus americanus) in eastern North America have a complex history of drastic population changes. Current and potential threats to moose populations in this region could be exacerbated by loss of genetic diversity and connectivity among subpopulations. Existing genetic diversity, gene flow, and population clustering and fragmentation of eastern North American moose are not well quantified, while physical and anthropogenic barriers to population connectivity already exist. Here, single nucleotide polymorphism (SNP) genotyping of 507 moose spanning five northeastern U.S. states and one southeastern Canadian province indicated low diversity, with a high proportion of the genomes sharing identity-by-state, with no consistent evidence of non-random mating. Gene flow estimates indicated bidirectionality between all pairs of sampled areas, with magnitudes reflecting clustering and differentiation patterns. A Discriminant Analysis of Principal Components analysis indicated that these genotypic data were best described with four clusters and indicated connectivity across the Saint Lawrence River and Seaway, a potential physical barrier to gene flow. Tests for genetic differentiation indicated restricted gene flow between populations across the Saint Lawrence River and Seaway, and between many sampled areas facing expanding human activity. These results document current genetic variation and connectivity of moose populations in eastern North America, highlight potential challenges to current population connectivity, and identify areas for future research and conservation.
      PubDate: 2023-01-16
       
  • Genomic evidence for three distinct species in the Erebia manto complex in
           Central Europe (Lepidoptera, Nymphalidae)

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      Abstract: Abstract A problem to implement conservation strategies is that in many cases recognized taxa are in fact complexes of several cryptic species. Failure to properly delineate species may lead to misplaced priorities or to inadequate conservation measures. One such species complex is the yellow-spotted ringlet Erebia manto, which comprises several phenotypically distinct lineages, whose degree of genomic isolation has so far not been assessed. Some of these lineages are geographically restricted and thus possibly represent distinct units with conservation priorities. Using several thousand nuclear genomic markers, we evaluated to which degree the bubastis lineage from the Alps and the vogesiaca lineage from the Vosges, are genetically isolated from the widespread manto lineage. Our results suggest that both lineages are genetically as strongly differentiated from manto as other taxonomically well separated sibling species in this genus from each other, supporting a delineation of bubastis and vogesiaca as independent species. Given the restricted and isolated range of vogesiaca as well as the disjunct distribution of bubastis, our findings have significant implication for future conservation efforts on these formerly cryptic species and highlight the need to investigate the genomic identity within species complexes.
      PubDate: 2023-01-10
       
  • Correction to: Using genetic analysis to estimate population size, sex
           ratio, and social organization in an Asian elephant population in conflict
           with humans in Alur, southern India

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      PubDate: 2023-01-09
       
  • Genomic evidence uncovers inbreeding and supports translocations in
           rescuing the genetic diversity of a landlocked seal population

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      Abstract: Abstract Fragmentation of isolated populations increases the risk of inbreeding and loss of genetic diversity. The endemic Saimaa ringed seal (Pusa hispida saimensis) is one of the most endangered pinnipeds in the world with a population of only ~ 400 individuals. The current genetic diversity of this subspecies, isolated in Lake Saimaa in Finland for ca. 1000 generations, is alarmingly low. We performed whole-genome sequencing on Saimaa ringed seals (N = 30) and analyzed the level of homozygosity and genetic composition across the individual genomes. Our results show that the Saimaa ringed seal population has a high number of runs of homozygosity (RoH) compared with the neighboring Baltic ringed seal (Pusa hispida botnica) reference population (p < 0.001). There is also a tendency for stillborn seal pups to have more pronounced RoH. Since the population is divided into semi-isolated subpopulations within the Lake Saimaa exposing the population to deleterious genomic effects, our results support augmented gene flow as a genetic conservation action. Based on our results suggesting inbreeding depression in the population, we recommend Pihlajavesi as a potential source and Southern Saimaa as a potential recipient subpopulation for translocating individuals. The Saimaa ringed seal is a recognized subspecies and therefore translocations should be considered only within the lake to avoid an unpredictable risk of disease, the introduction of deleterious alleles, and severe ecological issues for the population.
      PubDate: 2023-01-07
       
  • Genomic divergence of hatchery- and natural-origin Chinook salmon
           (Oncorhynchus tshawytscha) in two supplemented populations

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      Abstract: Abstract Captive propagation is widely used for the conservation of imperiled populations. There have been concerns about the genetic effects of such propagation, but few studies have measured this directly at a genomic level. Here, we use moderate-coverage (10X) genome sequences from 80 individuals to evaluate the genomic distribution of variation of several paired groups of Chinook salmon (Oncorhynchus tshawytscha). These include (1) captive- and natural-origin fish separated by at least one generation, (2) fish within the same generation having high fitness in captivity compared to those with high fitness in the wild, and (3) fish listed as different Evolutionarily Significant Units (ESUs) under the US Endangered Species Act. The distribution of variation between high-fitness captive and high-fitness natural fish was nearly identical to that expected from random sampling, indicating that differential selection in the two environments did not create large allele frequency differences within a single generation. In contrast, the samples from distinct ESUs were clearly more divergent than expected by chance, including a peak of divergence near the GREB1L gene on chromosome 28, a gene previously associated with variation in time of return to fresh water. Comparison of hatchery- and natural-origin fish within a population fell between these extremes, but the maximum value of FST was similar to the maximum between ESUs, including a peak of divergence on chromosome 8 near the slc7a2 and pdgfrl genes. These results suggest that efforts at limiting genetic divergence between captive and natural fish in these populations have successfully kept the average divergence low across the genome, but at a small portion of their genomes, hatchery and natural salmon were as distinct as individuals from different ESUs.
      PubDate: 2023-01-03
       
  • The potential and shortcomings of mitochondrial DNA analysis for cheetah
           conservation management

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      Abstract: Abstract There are only about 7,100 adolescent and adult cheetahs (Acinonyx jubatus) remaining in the wild. With the majority occurring outside protected areas, their numbers are rapidly declining. Evidence-based conservation measures are essential for the survival of this species. Genetic data is routinely used to inform conservation strategies, e.g., by establishing conservation units (CU). A commonly used marker in conservation genetics is mitochondrial DNA (mtDNA). Here, we investigated the cheetah’s phylogeography using a large-scale mtDNA data set to refine subspecies distributions and better assign individuals to CUs. Our dataset mostly consisted of historic samples to cover the cheetah’s whole range as the species has been extinct in most of its former distribution. While our genetic data largely agree with geography-based subspecies assignments, several geographic regions show conflicting mtDNA signals. Our analyses support previous findings that evolutionary forces such as incomplete lineage sorting or mitochondrial capture likely confound the mitochondrial phylogeography of this species, especially in East and, to some extent, in Northeast Africa. We caution that subspecies assignments solely based on mtDNA should be treated carefully and argue for an additional standardized nuclear single nucleotide polymorphism (SNP) marker set for subspecies identification and monitoring. However, the detection of the A. j. soemmeringii specific haplogroup by a newly designed Amplification-Refractory Mutation System (ARMS) can already provide support for conservation measures.
      PubDate: 2022-12-10
       
  • High genetic variation of Trifolium alpestre at the northern margin: but
           for how long'

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      Abstract: Abstract The maintenance of genetic variation is crucial at the margins of a species’ distribution range where plants grow in a suboptimal environment and often put less effort into sexual recruitment. The main focus of this study was on exploring the variation in genetic patterns and plant fitness of the long-lived clonal legume Trifolium alpestre in marginal populations in comparison to the distribution centre with the purpose to plan adequate conservation actions for this species. We used highly variable microsatellite loci to explore genetic patterns in 16 populations of varied size in Trifolium alpestre at the different parts of its range (marginal/central populations in Estonia, Poland and Czechia) of this species. We also studied overall genetic structure and population divergence, and historical and contemporary gene flow within each region. To estimate the potential for sexual reproduction at the marginal and central area, we measured the amount and weight of seeds produced in Estonian and Czech populations. Our study revealed high HE and AR in all studied populations that were unconnected with population size, and the occurrence of unique alleles both in central as well as in marginal northernmost (Estonian) populations. Overall genetic structure reflected the geographical location of populations. Very weak population structure together with high historical migration at the distribution margin imply a past, more continuous occurrence of T. alpestre in the northernmost region. Recent bottlenecks, lowered seed production and lighter seeds in marginal populations point to the local suboptimal conditions and indicate the need to pay more attention to management to prevent loss of genotypes and maintain diverse populations in this region.
      PubDate: 2022-12-07
       
  • Genetic restoration of black rhinoceroses in South Africa: conservation
           implications

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      Abstract: Abstract Globally, wildlife populations are becoming increasingly small and isolated. Both processes contribute to an elevated risk of extinction, notably due to genetic factors related to inbreeding depression and a loss of adaptive potential. Wildlife translocation is a valuable conservation tool to reintroduce species to previously occupied areas, or augment existing populations with genetically divergent animals, thereby improving the viability of endangered populations. However, understanding the genetic implications of mixing gene pools is key to avoid the risk of outbreeding depression, and to maximise translocation effectiveness. In this study we used mitochondrial and microsatellite DNA collected from 110 black rhinoceroses (Diceros bicornis minor) in Kruger National Park, South Africa, to determine levels of genetic diversity, inbreeding and relatedness. We compared this diversity with the two source populations (KwaZulu-Natal, South Africa and Zambezi River, Zimbabwe) using data from previously published studies, and assessed changes in the relative contribution of source lineages since their reintroduction in the 1970s. Our results show that Kruger’s black rhinoceroses are genetically more diverse than those from KwaZulu-Natal, with levels closer to those from the Zambezi Valley. Furthermore, our findings indicate a relative increase in the Zimbabwean lineage since reintroduction, suggesting a possible selective advantage. From a conservation perspective, our results demonstrate the benefits of mixing multiple source populations to restore gene flow, improve genetic diversity and thereby help protect small, isolated populations from extinction.
      PubDate: 2022-12-07
       
  • Historic DNA uncovers genetic effects of climate change and landscape
           alteration in two wild bee species

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      Abstract: Abstract Historic and contemporary data can shed light on a species’ conservation status and work together to address two main goals in conservation biology: (1) identifying species under extinction risk and (2) the forces shaping this process. Museomics is the study of historical DNA acquired from museum specimens that allows researchers to answer myriad questions across many taxa. Museomics is an effective way to understand how populations have been affected by human and climate factors from a historic perspective. Here, our goal is to investigate changes in wild populations of two small carpenter bee species (Ceratina calcarata and C. dupla) across a 50-year time span. We sampled museum specimens and recent collections to determine their genetic diversity, population structure, effective population size, signatures of selection, and local adaptation. Both species displayed reduced genetic diversity and effective population size through time. We identified signatures of adaptation in both species across human-altered land use and climate change scenarios. We found signatures of selection in genes related to biochemical defense, insecticide, and thermal tolerance, which are consistent with the observed increase in agricultural land use development and rising temperatures over the past 50 years. Our findings suggest that these species are facing population inbreeding, possibly attributable to human land-use change and agrochemicals in their environment. Overall, this study highlights the use of museomics to understand species declines, threats to populations, and targets for remediation.
      PubDate: 2022-12-06
       
 
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