 Subjects -> CONSERVATION (Total: 128 journals)
| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z | | The end of the list has been reached or no journals were found for your choice. |
|
|
- Ex situ versus in situ Eurasian lynx populations: implications for
successful breeding and genetic rescue-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The main aim of ex situ programmes in conservation is to provide a suitable source of individuals for future reintroductions or reinforcement of existing populations. A fundamental prerequisite is creating and maintaining healthy and sustainable captive populations that show high levels of phenotypic and genetic similarity to their wild counterparts. The Eurasian lynx (Lynx lynx) is a model of a locally extinct species that has been subject to long-term captive breeding and of past and ongoing reintroduction efforts. To test for genetic suitability of ex situ population, a comparative genetic evaluation including in situ populations was undertaken. The assignment analysis of 97 captive lynx from 45 European zoos, wildlife parks and private breeds was performed using 124 lynx from different wild Eurasian populations belonging to three evolutionary lineages: the Carpathian, the Northern, and the Siberian lynx. The results showed a high proportion of Siberian lynx (51%) in the European captive lynx population. Remaining captive animals were assigned to either the Carpathian (28%), or the Northern lynx lineage (13%). Admixture between lineages was rather low (8%). Notably, no or very low difference in genetic diversity was detected between the wild and captive lynx populations. Our results support the potential of the captive population to provide genetically suitable individuals for genetic rescue programmes. The transfer of genes between isolated populations, including those in captivity, should become an important management tool to preserve genetic variability and prevent inbreeding depression in native and reintroduced populations of this iconic predator.
PubDate: 2023-04-01
- Conservation genomics reveals fine-scale population structuring and recent
declines in the Critically Endangered Australian Kuranda Treefrog-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
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: 2023-04-01
- Genetic diversity goals and targets have improved, but remain insufficient
for clear implementation of the post-2020 global biodiversity framework-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
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: 2023-04-01
- Conservation genetics of Phlox hirsuta, a serpentine endemic
-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Identifying units for appropriate management and conservation of rare species is an important and challenging process, and population genetics can inform this decision making. Using Phlox hirsuta, a rare species restricted to serpentine soils in Northern California and with a geographic range of less than 15 km, we examined genetic variation within and among populations, using tunable Genotyping-by-Sequencing (tGBS) to generate single nucleotide polymorphisms (SNPs) as well as 11 microsatellite loci, to identify population structure, patterns of migration and selection, and units for conservation. Multiple methods recognized three geographically structured population clusters. The species has undergone a recent genetic bottleneck, and the increase in population size may be influenced by the changing climate. Patterns of gene flow are greater from south to north than in the opposite direction. Some of the genes under selection are putatively involved in adaptation to edaphic conditions, and genes under selection differ among the populations. Four population units were identified as suitable for conservation purposes based on various partitions of the SNPs.
PubDate: 2023-04-01
- Genomic evidence uncovers inbreeding and supports translocations in
rescuing the genetic diversity of a landlocked seal population-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
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: 2023-04-01
- Isolated on sky islands: genetic diversity and population structure of an
endangered mountain lizard-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Sky island species face climate-driven and anthropogenic habitat loss and population fragmentation, and are therefore vulnerable to genetic erosion. We conducted a genetic study of the cryptic and threatened alpine she-oak skink (Cyclodomorphus praealtus) throughout its range, across two regions of the mainland Australian Alps; an extensive high elevation plateau in the north (‘Kosciuszko Plateau’) and several smaller plateaus in the south (‘southern plateaus’). We investigated whether extensive potential habitat across Kosciuszko Plateau supported larger, connected populations with better genetic health than more fragmented southern plateaus. Our analyses of genome-wide markers confirmed effective isolation of the two regions. We identified three populations from the southern plateaus, largely aligning with discrete landforms, and four populations on Kosciuszko Plateau. Only one individual, from the southern-most population, showed evidence of admixture between the two regions. Across its range, C. praealtus populations had low genetic diversity and small effective population sizes. In contrast to our expectations, Kosciuszko Plateau populations were smaller, with greater genetic differentiation and a higher degree of inbreeding than the southern populations. We detected admixture between populations on Kosciuszko Plateau, while the southern plateaus had limited admixture. We found no evidence of local adaptation, suggesting plateaus represent interglacial refugia. Our results suggest that C. praealtus has little capacity to withstand further disturbance or rapid environmental changes. Maintaining or restoring habitat quality in occupied and suitable connecting habitats across the species’ range is paramount. ‘Genetic rescue’ should be investigated as an option to mitigate the effects of isolation and improve population resilience.
PubDate: 2023-04-01
- Effects of genomic homozygosity on total fitness in an invertebrate:
lethal equivalent estimates for Drosophila melanogaster-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Estimates of susceptibility to inbreeding depression for total fitness are needed for predicting the cost of inbreeding and for use in population viability analyses, but no such valid estimates are available for any wild invertebrate population. I estimated the number of lethals equivalents for total fitness in recently wild-caught populations of Drosophila melanogaster using published data on the total fitness of homozygosity versus heterozygosity for each of the major chromosomes (the X, second, and third) under competitive conditions. As there are no data for the fitness effects of homozygosity for the small fourth chromosome which represents 1.0% of the euchromatic genome, this was accounted for by attributing the homozygosity for the three large chromosome to an inbreeding coefficient of 0.99 when computing lethal equivalents for total fitness. Total genomic homozygosity is predicted to be essentially lethal in D. melanogaster. The corresponding haploid lethal equivalents estimate for total fitness was 5.04. The lethal equivalent value lies within the range for vertebrates but tends to be higher than for most outbreeding plants which are often purged as they exhibit up to 20% selfing (by definition). As D. melanogaster has its genome sequenced and annotated and has lethal equivalent estimates for total fitness for individual chromosomes as well as its total genome, it provides an excellent opportunity for evaluating genomic estimates of mutation load.
PubDate: 2023-04-01
- Genomic divergence of hatchery- and natural-origin Chinook salmon
(Oncorhynchus tshawytscha) in two supplemented populations-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
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: 2023-04-01
- Genetic diversity and connectivity of moose (Alces americanus americanus)
in eastern North America-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
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: 2023-04-01
- To all the gar I loved before: range-wide population genetic structure in
Alligator gar-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Managers and researchers have taken an increasing interest in Alligator gar (Atractosteus spatula). Conservation efforts are needed across much of the range where there are either declining populations or a growing popularity of Alligator gar as a trophy fish. Understanding the spatial patterns of genetic diversity and differentiation is necessary to guide management efforts. This study provides the most comprehensive examination to date of the range-wide genetic structure in Alligator gar with microsatellite genotype data for 935 individuals and mitochondrial control region sequence data from 696 individuals. Analysis of the microsatellite data identified 11 genetic groups representing three regional assemblages of populations. Two groups were from coastal areas or river systems, with the extreme western sites representing one of these groups. The third group comprised the interior portion of the range within the Mississippi River basin. The interior and peripheral coastal sites possessed lower levels of genetic diversity and estimates of effective population size. The mitochondrial data revealed similar patterns of genetic structure and diversity. Of the three haplogroups, one was widespread while the other two were either found in coastal sites and drainages or were restricted to the western portion of the range. Demographic analyses found evidence of demographic expansion in the two most widespread haplogroups, and haplotype diversity was lowest in interior sites. While there were still sampling gaps in our study, these results provide important baseline information for the management of Alligator gar populations and can serve to guide hatchery propagation and reintroduction programs.
PubDate: 2023-03-24
- Recent reduction of genetic diversity in markless form of the red-spotted
masu salmon Oncorhynchus masou ishikawae in the Ono River, Kyushu, Japan-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Markless form of masu Oncorhynchus masou masou and red-spotted masu salmon O. masou ishikawae (iwame) is distributed in a few rivers within Japan. Iwame is thought to be an intraspecific color variation that has evolved independently in each river. We investigated the genetic variation of iwame and red-spotted masu salmon (amago) in the Kohbaru River system using 21 microsatellite loci in 299 individuals collected in 2005 and 2013–2014. Overall, the genetic diversity within iwame was almost lost as of 2013 (allelic richness: 1.0–1.1, HE: 0.01–0.02), and all microsatellite loci were fixed, except for two loci. In comparisons between temporal samples (i.e., 2005 vs. 2013), a remarkable reduction of genetic diversity was observed within the iwame collected in the middle reach. In contrast, amago did not show a reduction of genetic diversity, although the levels of genetic diversity were very low (allelic richness: 1.4–2.7, HE: 0.14–0.40). The effective number of breeders using linkage disequilibrium (LD) method and the effective population size using temporal method were very small (LD Method: <45; temporal method: <17). Significant genetic differentiation was found among most iwame and amago samples despite their geographic proximity. This genetic differentiation is probably due to the recent genetic drift caused by the isolation and reduction of the population size. We suggest that continuous genetic monitoring focused on further loss of genetic diversity and genetic introgression of non-native amago should be prioritized to make management plans for long-term persistence of iwame and amago in this river.
PubDate: 2023-03-19
- Effects of subpopulation extinction on effective size (Ne) of
metapopulations-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Population extinction is ubiquitous in all taxa. Such extirpations can reduce intraspecific diversity, but the extent to which genetic diversity of surviving populations are affected remains largely unclear. A key concept in this context is the effective population size (Ne), which quantifies the rate at which genetic diversity within populations is lost. Ne was developed for single, isolated populations while many natural populations are instead connected to other populations via gene flow. Recent analytical approaches and software permit modelling of Ne of interconnected populations (metapopulations). Here, we apply such tools to investigate how extinction of subpopulations affects Ne of the metapopulation (NeMeta) and of separate surviving subpopulations (NeRx) under different rates and patterns of genetic exchange between subpopulations. We assess extinction effects before and at migration-drift equilibrium. We find that the effect of extinction on NeMeta increases with reduced connectivity, suggesting that stepping stone models of migration are more impacted than island-migration models when the same number of subpopulations are lost. Furthermore, in stepping stone models, after extinction and before a new equilibrium has been reached, NeRx can vary drastically among surviving subpopulations and depends on their initial spatial position relative to extinct ones. Our results demonstrate that extinctions can have far more complex effects on the retention of intraspecific diversity than typically recognized. Metapopulation dynamics need heightened consideration in sustainable management and conservation, e.g., in monitoring genetic diversity, and are relevant to a wide range of species in the ongoing extinction crisis.
PubDate: 2023-03-19
- Conservation genomics of an exploited, popular aquarium trade species: the
giant Caribbean sea anemone Condylactis gigantea (Anthozoa: Actiniidae)-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The marine aquarium trade in the United States operates primarily in Florida, and though the trade’s effects on many marine taxa are largely unknown, local declines have been observed for some harvested species. To reverse local declines in the abundance of the giant Caribbean sea anemone Condylactis gigantea, state managers prohibited harvest of this popular aquarium organism in late 2012. To assess the recovery of C. gigantea following the moratorium, we monitored relative abundance at 45 fixed locations in South Florida from 2013 to 2016. Seventeen of the sites were locations provided to us by commercial aquarium-trade collectors. The remaining sites were locations at which C. gigantea was presumably not being exploited. We found increased densities at only 4 of those 17 sites, while densities at the remaining sites remained unchanged. We also examined genome-wide single nucleotide polymorphism data to assess genetic diversity and population structure of 82 individuals from seven locations (three collection and four non-collection locations) across South Florida. Observed genetic diversity was comparable in all locations. But the location in the eastern Gulf of Mexico showed a significant FIS value, suggesting inbreeding that might be attributed to a small number of occupants. Condylactis gigantea is generally well mixed across South Florida, though a relatively weak pattern of genetic differentiation was detected. These results suggest limited reproductive success and dispersal that is restricted by hydrological and geographical barriers. We highlight the importance of periodic population and genetic monitoring to assess changes in relative abundance and genetic diversity.
PubDate: 2023-03-17
- Shifting range in a stingless bee leads to pre-mating reproductive
interference between species-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Human-induced shifts in species’ ranges can increase contact between closely related species and lead to reproductive interference. In Australia, climate change and trade in stingless bee colonies is increasing the range overlap of two cryptic species: Tetragonula carbonaria and T. hockingsi. To investigate reproductive interactions between these species, we validated a diagnostic-PCR test based on the mitochondrial gene COI to ID field specimens to species. We then assessed the likelihood of reproductive interference in four ways. First, we imaged the male genitalia of each species and found no evidence of reproductive character displacement. Second, we assessed species composition of mating aggregations in an area of sympatry (Southeast Queensland) and confirmed that some males join the mating aggregations of interspecific colonies. Third, we translocated T. hockingsi colonies into the southern range of T. carbonaria (Sydney) and tracked their ability to requeen. These translocated colonies attracted mating aggregations comprised almost entirely of interspecific males, but never formed hybrid colonies; instead, queens either mated with their brothers, or the colony failed to requeen at all. Finally, we presented T. carbonaria males with either conspecific or interspecific virgin queens and found that males attempted to mate only with their own species’ queens. In all, we conclude that reproductive barriers between these species are complete with respect to “short-range” mating cues, but not for “long-range” mate attraction cues. Our study highlights that hive movements can increase some forms of pre-mating reproductive interference between managed bee species, even where the species do not actually mate or hybridize.
PubDate: 2023-03-14
- A 37 K SNP array for the management and conservation of Golden Eagles
(Aquila chrysaetos)-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract We describe the development of a custom 37 K Affymetrix Axiom myDesign single nucleotide polymorphism (SNP) array for a culturally and ecologically important apex predator, the golden eagle (Aquila chrysaetos). Using this SNP array, we performed population genomic analysis on 154 individuals of known natal localities and detected three genetic clusters that we designated as Taiga/High Arctic, Great Basin, and Rocky Mountains/Great Plains. Each of these clusters appears to display clinal variation within these geographic regions. After determining genetic structure, we performed an assignment test of 32 individuals, five of which were siblings of individuals used in the assessment of genetic structure, three had associated telemetry data, and the remaining individuals were of unknown natal locations. Using this array, four siblings were correctly assigned to the same geographic region as their sibling and the genetic assignment of the radio telemetered birds agreed with the expected movement patterns displayed by these individuals. For the remaining individuals, we were able to assign all but five individuals to one of the three genetic clusters. Our genetic assignments illustrates the utility of this SNP array to accurately assign most individuals to predesignated geographical regions. While further compiling genetic and other data types, we can increase the power of this tool for identifying those breeding populations that may need assistance due to anthropogenic stressors that negatively impact their population viability. The use of this genetic resource will help substantiate decisions by multiple conservation groups that seek to preserve the natural population structure of the golden eagle.
PubDate: 2023-03-14
- Conservation genetics of the tropical gar (Atractosteus tropicus,
Lepisosteidae)-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The tropical gar (Atractosteus tropicus) is the smallest member of the family Lepisosteidae; yet this species has a large socioeconomic impact in México and Central America where it is traditionally harvested commercially and for subsistence. While natural populations of tropical gar have been dwindling throughout its natural range, it is also an emergent aquaculture species that is produced in local hatcheries and grown out in privately owned ponds. The increased pressure on natural populations of A. tropicus and its increasing use in aquaculture production poses potential conflicts for the management and conservation of natural populations. Here, we investigated the population genetic structure of tropical gar populations, including over 200 individuals sampled in México, El Salvador, and Costa Rica. Using 11 microsatellite loci, we identified three genetic clusters with distinct geographic distributions, including a cluster in drainages along the Pacific versant of Central America, a cluster in the Grijalva and Usumacinta River basins that drain into the Gulf of México, and a cluster in the Río San Juan that drains into the Caribbean Sea. Given the degree of divergence observed, these results indicate the potential presence of evolutionary significant units within tropical gar that warrant separate fisheries and conservation management. We also found that tropical gar from an aquaculture facility along the Pacific versant of México were derived from Atlantic versant populations, indicating that individuals have already been translocated across biogeographic boundaries. We discuss how such translocations can negatively impact the natural population structure of tropical gar and provide recommendations for future research and aquaculture practices.
PubDate: 2023-03-06
- Fine-scale functional connectivity of two syntopic pond-breeding
amphibians with contrasting life-history traits: an integrative assessment
of direct and indirect estimates of dispersal-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Assessing patterns of functional connectivity among amphibian demes is crucial to unravel their population dynamics and prevent their isolation and eventual extinction. Integrative studies based on direct (capture-mark-recapture) and indirect (genetic) estimates of dispersal provide robust, biologically realistic inferences on population structure and connectivity, with applications for conservation efforts. We focused on two pond-breeding amphibians with contrasting life-history traits: the short-lived, semi-arboreal Hyla molleri and the long-lived, fossorial Pelobates cultripes. We PIT-tagged 2150 individuals of both species in two ponds (Laguna and Gravera, separated by 700 m) and monitored them from 2009 to 2021 to document the frequency and spatial extent of dispersal events. In addition, we genotyped individuals from these and two additional breeding populations at a maximum distance of 5 km with 15–16 microsatellites to characterize fine-scale patterns of genetic structure. We detected dispersal events connecting Laguna and Gravera in both species, albeit at low frequencies (4.8% and 7.7% of recaptured individuals of H. molleri and P. cultripes, respectively). However, both species were capable of covering long distances, with individual accumulated displacements up to 3.5 km (Hyla) and 1.8 km (Pelobates). Breeding populations > 2 km apart were genetically differentiated, indicating lower connectivity at this spatial scale. Estimates of pairwise migration rates differed between species and were asymmetrical, with different ponds representing “source” populations contributing more migrants to other populations in each species. We discuss the role of differences in life history traits and ecological preferences in shaping population dynamics in the two species and highlight management implications of our results.
PubDate: 2023-02-25
- Landscape genetics identifies barriers to Natterjack toad metapopulation
dispersal-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Habitat fragmentation and loss reduce population size and connectivity, which imperils populations. Functional connectivity is key for species persistence in human-modified landscapes. To inform species conservation management, we investigated spatial genetic structure, gene flow and inferred dispersal between twelve breeding sites of the Natterjack toad (Bufo calamita); regionally Red-Listed as Endangered in Ireland. Spatial genetic structure was determined using both Bayesian and non-Bayesian clustering analysis of 13 polymorphic microsatellite loci genotyping 247 individuals. We tested the influence of geographic distance, climate, habitat, geographical features, and anthropogenic pressure on pairwise genetic distances between breeding sites using Isolation-by-distance and Isolation-by-resistance based on least-cost path and circuit theory models of functional connectivity. There was clear spatial structuring with genetic distances increasing with geographic distance. Gene flow was best explained by Isolation-by-resistance models with coniferous forestry plantations, bog, marsh, moor and heath, scrub, anthropogenic presence (Human Influence Index) and rivers (riparian density) identified as habitats with high resistance to gene flow while metapopulation connectivity was enhanced by coastal habitats (beaches, sand dunes and salt marshes) and coastal grassland. Despite substantial declines in census numbers over the past 15 years and its regional status as Endangered, the Natterjack toad population in Ireland retains high genetic diversity. If declines continue, maintaining habitat connectivity to prevent genetic erosion by management of coastal grasslands, pond construction and assisted migration through translocation will be increasingly important.
PubDate: 2023-02-21
- Conservation genomics reveals low connectivity among populations of
threatened roseate terns (Sterna dougallii) in the Atlantic Basin-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract While the effects of barriers to dispersal such as population declines, habitat fragmentation, and geographic distance have been well-documented in terrestrial wildlife, factors impeding the dispersal of highly vagile taxa such as seabirds are less well understood. The roseate tern (Sterna dougallii) is a globally distributed seabird species, but populations tend to be both fragmented and small, and the species is declining across most of its range. We evaluated structuring of roseate tern populations in the Northwestern Atlantic, the Caribbean, and the Azores using both microsatellite markers and single-nucleotide polymorphisms generated through targeted sequencing of Ultra-conserved Elements. For both marker types, we found significant genetic differentiation among all 3 populations and evidence for moderate contemporary unidirectional gene flow from the Caribbean to the Azores, but not between other populations. Within the Caribbean population, we found high rates of unidirectional migration from the Virgin Islands to Florida, potentially indicative of movement from source population to sink or an artifact of dispersal among other unsampled populations in the Caribbean region. These observations have significance for species persistence in the Atlantic, as our results indicate that loss of genetic diversity within populations is unlikely to be buffered by inflow of new alleles from other breeding populations.
PubDate: 2023-02-20
- Correction: Conservation genetics of Phlox hirsuta, a serpentine endemic
-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
PubDate: 2023-02-13
|
Hybrid journal (It can contain Open Access articles)
