Find research datasets worth reusing

opencc-zeroMay 2022View details →

Exceptional longevity in northern peripheral populations of Wels catfish (Silurus glanis)

Studies of life-history variation across a species range are crucial for ecological understanding and successful conservation. Here, we examined the growth and age of Wels catfish (Silurus glanis) in Sweden, which represent the northernmost populations in Europe. A total of 1183 individuals were captured, marked and released between 2006 and 2020. Mark-recapture data from 162 individuals (size range: 13–195 cm) were used to estimate von Bertalanffy growth curve parameters which revealed very slow growth rates compared to catfish within the core distribution area (central Europe). The fitted von Bertalanffy growth curve predicted a 150 cm catfish to be around 40 years old, while the largest recaptured individual (length 195 cm) was estimated to be 70 (95% CI 50–112) years old. This was substantially older than the previously documented maximum age of a catfish. The weight at length relationships in these northern peripheral populations were similar to those documented for catfish in central Europe indicating that resources did not constrain growth. This indicates that the slow growth and exceptional high age in the northern catfish populations are the result of lower temperatures and/or local adaptations.

opencc-zeroSep 2023View details →

Evaluating the use of non‐invasive hair sampling and ddRAD to characterize populations of endangered species: Application to a peripheral population of the European mink

The application of next‐generation sequencing (NGS) to non‐invasive samples is one of the most promising methods in conservation genomics, but these types of samples present significant challenges for NGS. The European mink (Mustela lutreola) is critically endangered throughout its range. However, important aspects such as census size and inbreeding remain still unknown in many populations, so it is crucial to develop new methods to monitor this species. In this work, we placed hair tubes along riverbanks in a border area of the Iberian population, which allowed the genetic identification of 76 European mink hair samples. We then applied a reduced representation genomic sequencing (ddRAD) technique to a subset of these samples to test whether we could extract sufficient genomic information from them. We show that several problems with the DNA, including contamination, fragmentation, oxidation, and possibly sample mixing, affected the samples. Using various bioinformatic techniques to reduce these problems, we were able to unambiguously genotype 19 hair samples belonging to six individuals. This small number of individuals showed that the demographic status of the species in this peripheral population is worse than expected. The data obtained also allowed us to perform preliminary analyses of relatedness and inbreeding. Although further improvements in sampling and analysis are needed, the application of the ddRAD technique to non‐invasively obtained hairs represents a significant advance in the genomic study of endangered species.

publicAug 2024View details →

Data from: Genome-wide SNP assessment of contemporary European red deer genetic structure highlights the distinction between peripheral populations and the main admixture zones in Europe

Open the record for dataset details and reuse information.

publicMay 2025View details →

Data from: Microsite availability, not floral herbivory, limits recruitment in peripheral native thistle populations

Open the record for dataset details and reuse information.

publicSep 2023View details →

Evaluating the use of non‐invasive hair sampling and ddRAD to characterize populations of endangered species: Application to a peripheral population of the European mink

Open the record for dataset details and reuse information.

publicMay 2022View details →

Exceptional longevity in northern peripheral populations of Wels catfish (Silurus glanis)

Open the record for dataset details and reuse information.

opencc-zeroDec 2016View details →

Data from: Variation in fine-scale genetic structure and local dispersal patterns between peripheral populations of a South American passerine bird

The distribution of suitable habitat influences natal and breeding dispersal at small spatial scales, resulting in strong micro-geographic genetic structure. Although environmental variation can promote inter-population differences in dispersal behavior and local spatial patterns, the effects of distinct ecological conditions on within-species variation in dispersal strategies and in fine-scale genetic structure remain poorly understood. We studied local dispersal and fine-scale genetic structure in the thorn-tailed rayadito (Aphrastura spinicauda), a South American bird that breeds along a wide latitudinal gradient. We combine capture-mark-recapture data from eight breeding seasons and molecular genetics to compare two peripheral populations with contrasting environments in Chile: Navarino Island, a continuous and low density habitat, and Fray Jorge National Park, a fragmented, densely populated and more stressful environment. Natal dispersal showed no sex bias in Navarino, but was female-biased in the more dense population in Fray Jorge. In the latter, male movements were restricted and some birds seemed to skip breeding in their first year, suggesting habitat saturation. Breeding dispersal was limited in both populations, with males being more philopatric than females. Spatial genetic autocorrelation analyses using 13 polymorphic microsatellite loci confirmed the observed dispersal patterns: a fine-scale genetic structure was only detectable for males in Fray Jorge for distances up to 450 m. Furthermore, two-dimensional autocorrelation analyses and estimates of genetic relatedness indicated that related males tended to be spatially clustered in this population. Our study shows evidence for context-dependent variation in natal dispersal and corresponding local genetic structure in peripheral populations of this bird. It seems likely that the costs of dispersal are higher in the fragmented and higher density environment in Fray Jorge, particularly for males. The observed differences in micro-geographic genetic structure for rayaditos might reflect the genetic consequences of population-specific responses to contrasting environmental pressures near the range limits of its distribution.

opencc-zeroSep 2019View details →

Data from: Evidence of genetic erosion in a peripheral population of a North American game bird: the Montezuma quail (Cyrtonyx montezumae)

Population extirpations are often precursors to species extinctions. Anthropogenic activities often lead to smaller populations that are more prone to extirpations and advocates for active conservation management have recently called for the preservation and monitoring of genetic diversity, particularly with regard to the adaptive potential of vulnerable populations. We used genomics and curated arrays of molecular markers, including those expected to impact key fitness traits, to quantify evidence of genomic erosion in core and peripheral populations of a gallinaceous bird. The Montezuma quail (Cyrtonyx montezumae) is a game species considered vulnerable to extirpation in Texas, but core populations in Arizona and New Mexico are robust and have the potential to serve as genetic reservoirs. We sequenced the Montezuma quail genome then developed a single nucleotide polymorphism (SNP) assay to quantify genetic variation, effective population sizes, signatures of natural selection, and population structure. We genotyped SNPs from gene deserts and from genes associated with fitness traits and found the isolated Texas population exhibits an extremely small effective population size, is genetically distinct from our Arizona and New Mexico samples, and has reduced heterozygosity at the fitness-related markers. Thus, our samples from Texas exhibit symptoms of genetic erosion that could exacerbate future risk of local extirpation. Management agencies must decide if active conservation efforts such as assisted gene flow or genetic rescue are now warranted. This decision may not be straightforward because the current conservation status of the Texas population reflects its isolated geographic locale on the periphery of the species' range.

opencc-zeroDec 2009View details →

Data from: Implications of isolation and low genetic diversity in peripheral populations of an amphi-Atlantic coral

Limited dispersal and connectivity in marine organisms can have negative fitness effects in populations that are small and isolated, but reduced genetic exchange may also promote the potential for local adaptation. Here, we compare the levels of genetic diversity and connectivity in the coral Montastraea cavernosa among both central and peripheral populations throughout its range in the Atlantic. Genetic data from one mitochondrial and two nuclear loci in 191 individuals show that M. cavernosa is subdivided into three genetically distinct regions in the Atlantic: Caribbean-North Atlantic, Western South Atlantic (Brazil) and Eastern Tropical Atlantic (West Africa). Within each region, populations have similar allele frequencies and levels of genetic diversity; indeed, no significant differentiation was found between populations separated by as much as 3,000 km, suggesting that this coral species has the ability to disperse over large distances. Gene flow within regions does not, however, translate into connectivity across the entire Atlantic. Instead, substantial differences in allele frequencies across regions suggest that genetic exchange is infrequent between the Caribbean, Brazil and West Africa. Furthermore, markedly lower levels of genetic diversity are observed in the Brazilian and West African populations. Genetic diversity and connectivity may contribute to the resilience of a coral population to disturbance. Isolated peripheral populations may be more vulnerable to human impacts, disease or climate change relative to those in the genetically diverse Caribbean-North Atlantic region.

opencc-zeroJul 2019View details →

Data from: Repeated jumps from Northwest Africa to the European continent: the case of peripheral populations of an annual plant

Peripheral populations (i.e., those occurring on the edge of a species' distribution range) can have different origins and genetic characteristics, and they may be critical for conservation of genetic diversity. We investigated European peripheral populations of Scrophularia arguta, a widespread, annual plant distributed from Arabia to Northwest Africa and Macaronesia. Only two small disjunct population groups of this species occur in Europe, specifically in West‐Central and Southeast Iberia. To disclose the origin of these populations and determine their importance for conservation of S. arguta genetic diversity, we analysed DNA sequences from two nuclear and two plastid regions and AFLP markers in populations sampled mainly across the western distribution range of the species, and modelled the species distribution under present and late Quaternary conditions. The analyses revealed the presence of three distinct lineages of S. arguta in Europe, as a result of multiple colonisation waves at different times in the Quaternary. Two of these lineages, occurring in Southeast Iberia, are the result of more or less recent dispersal from Northwest Africa. In contrast, West‐Central Iberian populations are strongly differentiated from the remaining range of S. arguta, and can be considered as peripheral relict populations. Our study is the first to demonstrate the occurrence of at least three colonisations of the European continent from Africa by a native plant species. The diverse histories and genetic makeup of resulting populations confirm the importance of peripheral populations, and particularly of ancient relict populations, for conservation of global genetic diversity in widespread species.

opencc-zeroDec 2013View details →

Data from: Critically endangered island endemic or peripheral population of a widespread species? Conservation genetics of Kikuchi's gecko and the global challenge of protecting peripheral oceanic island endemic vertebrates

Aim: To highlight the significant conservation challenge of evaluating peripheral endemic vertebrates in island archipelago systems and to assess empirically the complexities of approaches to conservation genetic studies across political and biogeographic boundaries. To demonstrate the poignant need for international collaboration and coordination when species delimitation problems with high conservation concern involve island endemics with biogeographically peripheral ranges. Location: Southeast Asia, Lanyu Island, Taiwan, and the Philippines. Methods: Genetic samples were collected and sequenced for one mitochondrial gene and five nuclear loci for species of the Gekko mindorensis-G. kikuchii species complex in Southeast Asia. We used maximum likelihood and Bayesian phylogenetic methods and coalescent-based species delimitation analyses to estimate phylogeographic relationships, construct multilocus haplotype networks and test putative species boundaries. Results: Phylogenetic and population genetic analyses suggest that Kikuchi's Gecko may represent a peripheral population of a widespread species distributed from the northern Philippines to Taiwan. However, we identify a discrepancy between inferences of species boundaries resulting from methods based on allele frequencies versus coalescent-based methods that incorporate evolutionary history. Coalescent-based analyses suggest that G. kikuchii may be a distinct evolutionary lineage. Our study underscores the need for coalescent-based methods in conjunction with population genetic approaches for conservation genetic assessments of widespread species. Main conclusions: This study joins a few recent works suggesting that Philippine-derived anomalies in the fauna of Lanyu (and possibly greater Taiwan) are worthy of careful reconsideration. Determining whether each is the result of recent human-mediated introduction or (possibly more ancient) natural dispersal should be the goal of future studies on this seldom-conceived biogeographic relationship. Isolated species endemic to islands on the outer periphery of biogeographic and political regions represent particular conservation challenges. This is especially true if a species occurs on an isolated island that is allied biogeographically with one nation, but politically administered by another.

opencc-zeroDec 2011View details →

Data from: Effect of habitat fragmentation on the genetic diversity of peripheral populations of beech in Central Italy

Fragmentation can affect the demographic and genetic structure of populations near the boundary of their bio-geographic range. Higher genetic differentiation among populations coupled with lower level of within population variability is expected as a consequence of reduced population size and isolation. The effects of these two factors have been rarely disentangled. Given their high gene flow, anemophilous forest trees should be more affected, in terms of loss of genetic diversity, by small population size rather than geographic isolation alone. We studied the impact of distance from the main range (a measure of isolation) and reduced population size on the within and among population components of genetic variability. We assayed 11 isozyme loci in 27 marginal populations of European beech (Fagus sylvatica L.) in Central Italy. Populations were divided in three groups with an increasing level of fragmentation. In the most fragmented group the within population genetic variability was slightly smaller and the among population differentiation significantly larger than in the other two groups. These results support the role of random genetic drift having a larger impact on the most fragmented group, while gene flow seems to balance genetic drift in the two less fragmented ones. Given that average distance from the main range is not different between the intermediate and the most fragmented group, but average population size is smaller, we can conclude that gene flow is effective, even at relatively long distances, in balancing the effect of fragmentation if population size is not too small.

opencc-zeroJun 2022View details →

Genetic structure and dispersal in peripheral populations of a marine fish (Pacific cod, Gadus macrocephalus) and their importance for adaptation to climate change

Small and isolated peripheral populations, which are often remnants of glacial refugia, offer an opportunity to determine the magnitude and direction of fine-scale connectivity in high gene flow marine species. When located at the equatorial edge of a species' range, these populations may also harbor genetic diversity related to survival and reproduction at higher temperatures, a critical resource for marine species facing warming ocean temperatures. Pacific cod (Gadus macrocephalus), a marine fish in the North Pacific, has already experienced major shifts in biomass and distribution linked to climate change. We estimated the magnitude and direction of connectivity between peripheral populations of Pacific cod at the southern edge of the species' range, by conducting restriction site-associated DNA (RAD) sequencing and individual assignment on fish collected around the Korean Peninsula during the spawning season. Three populations on the western, eastern, and southern Korean coasts were highly differentiated (FST =0.025 – 0.042) and relatively small (Ne = 433-1777). Ten putative dispersers and estimates of contemporary migration rates revealed asymmetrical, west-to-east movement around the Korean Peninsula, at a higher rate than predicted by indirect estimates of connectivity (FST). Allele frequencies at 87 RAD loci were decisively correlated with strong marine temperature gradients between the warmer southern coast and the cooler waters of the eastern and western coasts. Despite relatively small sample sizes, our data suggest asymmetrical dispersal and gene flow, potentially involving adaptive alleles, between peripheral populations inhabiting markedly different thermal regimes. Our study emphasizes the conservation value of peripheral populations in high gene flow marine fish species.

Figure 6 in Limited genetic depletion despite extinction risk: genomic diversity of a peripheral population of red-spotted bluethroats in Central Europe

Figure 6. Manhattan plots showing SNP levels of ROH per autosome for A, All L. s. svecica individuals, B, Sve_Krk population. The Manhattan plot portrays ROH analysis across 28 autosomes. The height of the peak represents the percentage of individuals sharing homozygous SNP per ROH.

Figure 4 in Limited genetic depletion despite extinction risk: genomic diversity of a peripheral population of red-spotted bluethroats in Central Europe

Figure 4. SNP-based analyses of population structure. A, discriminant analysis of the principal components (DAPC) analysis of genetic structure for two subspecies' genetic clusters (on the left) and, B, for seven populations (on the right). Each colour shade represents subspecies or population genetic clusters, respectively. Every point represents an individual, while inertia ellipses represent 67% of the individuals. Discriminant analysis eigenvalues are displayed by small insets. C, admixture analysis for K = 2. Each vertical bar shows an individual level of shared ancestry between the two subspecies. The two bands below the admixture plot mark individual's subspecies and population affiliation, respectively.

Figure 5 in Limited genetic depletion despite extinction risk: genomic diversity of a peripheral population of red-spotted bluethroats in Central Europe

Figure 5. Pairwise FineRADStructure co-ancestry analysis of 148 genotyped specimens. Ancestral population labels are displayed on the vertical and horizontal axes. Upper horizontal bar stands for subspecies genetic clusters: L. s. svecica—left label, intermediate—centre, L. s. cyanecula—right. Lower horizontal bar depicts population origin if the individuals using the same coding as in Fig. 3.

Figure 3 in Limited genetic depletion despite extinction risk: genomic diversity of a peripheral population of red-spotted bluethroats in Central Europe

Figure 3. The Cytb haplotype network of red-spotted and white-spotted bluethroat populations. Pie charts illustrate the haplotype variants shared among populations. Each circle represents a unique haplotype variant. Sizes of the circles are proportional to the number of individuals. Hatch marks on the branches represent the number of mutational steps that separate haplotypes. Black circles represent hypothetical haplotypes. Red-spotted bluethroat populations are: 1. Krkonoše Mountains (Sve_Krk); 2. Kola (Sve_Klp); 3. Abisko (Sve_Abi). Whitespotted populations are: 1. Třeboňsko (Cya_Trb); 2. St Petersburg (Cya_Stp); 3. Vomáčka (Cya_Vmk); 4. Krkonose Mountains (Cya_Krk). The haplotype marked with the red asterisk is a shared haplotype found in both subspecies.

Figure 1 in Limited genetic depletion despite extinction risk: genomic diversity of a peripheral population of red-spotted bluethroats in Central Europe

Figure 1. Locations of sampled individuals of red-spotted (L. s. svecica) and white-spotted (L. s. cyanecula) bluethroat. L. s. svecica locations: Kola peninsula, Russia (Sve_Klp); Abisko, Sweden (Sve_Abi) and Krkonoše Mountains, Czech Republic (Sve_Krk). L. s. cyanecula locations are: Krkonoše Mountains, Czech Republic (Cya_Krk); Vomáčka, Czech Republic (Cya_Vmk);Třeboňsko, Czech Republic (Cya_Trb) and St. Petersburg, Russia (Cya_Stp). Inset: close-up of the populations in the Czech Republic.