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Aim Human‐induced environmental changes result in habitat loss and fragmentation, impacting wildlife population genetic structure and evolution. Urbanised and geographically peripheral areas often represent unfavourable environments, reducing connectivity among populations and causing higher population genetic differentiation and lower intra‐population genetic diversity. We examined how geographic peripherality and anthropogenic pressures affect genetic diversity and genetic differentiation in the protected southern damselfly (Coenagrion mercuriale, Odonata), which has low dispersal capabilities and specific habitat requirements and whose populations are declining. Location We studied two areas: one in semi‐natural habitats at the periphery of the species geographic range (northern France) and the other more central to the species' range, in an urbanised area surrounding the city of Strasbourg (Alsace, eastern France). Methods We genotyped 2743 individuals from 128 populations using 11 microsatellite loci. We analysed the spatial distribution of neutral genetic diversity (allelic richness, heterozygosity, levels of inbreeding and genetic relatedness), the extent of genetic differentiation and population affiliations (sPCAs) within the two areas. We also examined fine‐scale patterns of gene flow in the urbanised area of Alsace by investigating patterns of isolation by distance and estimating effective migration surfaces (EEMS) method. Results Northern peripheral populations showed lower levels of genetic diversity and higher levels of genetic differentiation than central Alsacian populations. Although located in anthropised habitats, geographically central Alsacian populations showed high levels of gene flow, with dispersal events mainly occurring overland and not restricted to watercourses. However, the highly urbanised city of Strasbourg negatively impacted nearby populations by reducing levels of genetic diversity and increasing population genetic differentiation. Main Conclusions These results showed the need for management action by restoring breeding sites and creating migratory corridors for peripheral southern damselfly populations. However, our results also highlighted the resilience of southern damselfly in central range populations facing strong urbanisation pressures.

Effective management and conservation of peripheral populations require an understanding of the landscape conditions inhibiting dispersal and spatially explicit predictions of connectivity. Here, we modeled landscape resistance and genetic connectivity for the western population of an American badger subspecies (Taxidea taxus jeffersonii) across 170,000 km2 in southern British Columbia, Canada, using 116 genetic samples genotyped at 14 microsatellite loci. We used gradient boosting machine models in a corridor‐based approach to predict genetic distances between pairs of individual badgers as a function of landscape variable data. Spatial genetic autocorrelation tests and our top model predicted that genetic similarities of T. t. jeffersonii were present up to 110 km. Gene diversity was lowest in the Cariboo region in the northwest portion of the study area and highest in the Okanagan region in the southeast. Our analyses suggest that the genetic connectivity of T. t. jeffersonii was impeded by colluvial soil parent material, geographic distance, steep slopes, and major roads, but was facilitated by organic and fluvial soil parent materials, and areas with relatively little snow cover during winter. Our predictive maps of landscape resistance and connectivity can help guide management actions such as habitat protection and underpass placement on major roads to promote genetic connectivity. We used a machine‐learning, corridor‐based approach to model landscape resistance and genetic connectivity for an endangered population of American badgers in southern British Columbia, Canada. We found that genetic connectivity in badgers was impeded by colluvial soil parent material, geographic distance, steep slopes, and major roads, but was facilitated by organic and fluvial soil parent materials and areas with relatively little snow cover during winter.

Ocean warming is one of the most important factors in shaping the spatial distribution and genetic biodiversity of marine organisms worldwide. The northwest Pacific has been broadly illustrated as an essential seaweed diversity hotspot. However, few studies have yet investigated in this region on whether and how past and ongoing climate warming impacted the distribution and genetic pools of coastal seaweeds. Here, we chose the invasive species Gracilaria vermiculophylla as a model, and identified multiple genetic lineages in the native range through genome-scale microsatellite genotyping. Subsequently, by reconstructing decadal trends of sea surface temperature (SST) change between 1978 and 2018, we found that SST in northern Japan and the East China Sea indeed increased broadly by 0.25-0.4 degrees C/decade. The projections of species distribution models (SDMs) under different future climate change scenarios (RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5) indicated that a unique genetic pool of G. vermiculophylla at its current southern range limit (i.e. the South China Sea) is at high risk of disappearance, and that the populations at its current northern range limit (i.e. in Hokkaido region) will undergo poleward expansions, particularly by the year 2100. Such responses, along with this species' limited dispersal potential, may considerably alter the contemporary distribution and genetic composition of G. vermiculophylla in the northwest Pacific, and ultimately threaten ecological services provided by this habitat-forming species and other associated functional roles.

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 = 433–1,777). 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. When located at the equatorial edge of a species’ range, small and isolated peripheral populations may harbor genetic diversity related to survival and reproduction at higher temperatures—a critical resource for adaptation to warming oceans. We use restriction site‐associated DNA (RAD) sequencing and individual assignment to reveal west‐to‐east movement of Pacific cod (Gadus macrocephalus) between highly differentiated peripheral populations around the Korean Peninsula. A total of 87 RAD loci had allele frequencies decisively correlated with strong marine temperature gradients between the warmer southern population and the cooler eastern and western populations. Our data suggest asymmetrical dispersal and gene flow, potentially involving adaptive alleles, between peripheral populations of a marine fish inhabiting markedly different thermal regimes.

How genetic diversity is maintained within a range of species is one of the crucial pieces of information in species conservation. Although the classical central-marginal hypothesis assumes genetic paucity in peripheral populations, this pattern is not always the case. The semi-shrub Chimaphila umbellata subsp. umbellate, population of which are located in the southernmost part of the subspecies distribution, is considered to be a threatened species in Japan. Thus, this study aimed to examine which populations should be preferentially conserved and if the central-marginal hypothesis can be applied to this case. Genetic diversity was examined in 15 populations of C. umbellata subsp. umbellata in Japan using 16 nuclear simple sequence repeat markers. Overall, the genetic diversity values within the populations did not correlate with the latitude of the population locality, although those of the southern marginal populations tended to be lower than those of populations in other regions. While the populations are genetically differentiated from each other, recent population size declines were only detected in a few cases. Bayesian inference of population structure revealed three genetically distinct groups. An approximate Bayesian computation revealed that these three genetic groups were derived from the ancient population in a recent times. The contribution of each population to total genetic diversity was estimated by removing a given population and recalculating the total genetic diversity. Only one population contributed to both gene diversity and allelic diversity, while several populations contributed to one or the other. Considering genetic diversity and structure, the conservation priority of Japanese populations of C. umbellata to preserve genetic diversity is discussed.

Understanding tree species responses to climate change is crucial for preserving biodiversity especially in Southern Europe hot spots where Abies alba is widely spread. Three Apennine silver fir populations, Pigelleto (PIG), La Verna (LV) and Bocca Trabaria (BT), ensured gene flows in interglacial periods between the two phylogenetically different groups of northern and southern Apennines. These stands were analysed (nuclear and chloroplast SSRs) with the aim to establish a baseline for their future management in view of the expected changes. The three forests were tested for the Centre-Periphery Hypothesis (CPH) compared to forty-five Italian populations. At the same time, permanent areas were surveyed within LV and PIG on dominant (a) and dominated or natural regeneration (r) tree layers, and on age classes. In two consecutive years, spring cambial phenology activity was also weekly monitored on microcores, and critical phenology dates recorded. The stands matched CPH only partially, showing different phylogenetic history and their bridging between northern and southern groups of silver fir populations was confirmed. LV was distinct from PIG and BT. The within-population variance component was significantly high, and no narrow relatedness was observed between dominant and dominated/regeneration spatially closer trees, and genetic parameters were comparable in both layers at LV and PIG. In both stands, older age classes ensured natural regeneration. Cambium phenology was highly variable within populations, consistently to other Mediterranean conifers, and highly sensitive to local and year's conditions and monitoring will improve population's adaptive capacity detection. Shelterwood-system silvicultural treatments are suggested on small areas to drive the demographic and panmictic balance towards an uneven-aged more resilient structure, and iterated monitoring will help to adapt the forest management to the isotherm shift.

Populations at the far edges of their ranges tend to be scarce, and they are frequently of conservation concern. This paper examines the distribution of three raptors (Circaetus gallicus, Hieraaetus pennatus and Milvus migrans) at the southwestern boundary of their breeding range. We modelled species distribution to obtain habitat suitability indexes that were validated with extensive fieldwork in Morocco and Spain. Our results support a strong effect of habitat suitability and a bottleneck effect of the Strait of Gibraltar on raptor distribution. However, after controlling for these effects, the three species were scarcer in Morocco than in Spain. We did not find differences between the two countries in the number of power lines that are dangerous to raptors or in general impacts of agricultural intensification on bird populations (we assessed more farmland birds in Morocco). However, many more people (i.e., shepherds) were detected in Morocco, whose negative effect on raptors could explain the depletion of their populations. These transboundary differences are used to discuss the fate of these peripheral populations in a context of climate change and rural abandonment. They also highlight the need for strengthening raptor conservation around the Strait of Gibraltar, where a permanent flow of raptors converges throughout the year.

Understanding how biological and environmental factors interactively shape the global distribution of plant and animal genetic diversity is fundamental to biodiversity conservation. Genetic diversity measured in local populations (GD P ) is correspondingly assumed representative for population fitness and eco-evolutionary dynamics. For 8356 populations across the globe, we report that plants systematically display much lower GD P than animals, and that life history traits shape GD P patterns both directly (animal longevity and size), and indirectly by mediating core-periphery patterns (animal fecundity and plant dispersal). Particularly in some plant groups, peripheral populations can sustain similar GD P as core populations, emphasizing their potential conservation value. We further find surprisingly weak support for general latitudinal GD P trends. Finally, contemporary rather than past climate contributes to the spatial distribution of GD P , suggesting that contemporary environmental changes affect global patterns of GD P . Our findings generate new perspectives for the conservation of genetic resources at worldwide and taxonomic-wide scales. A global analysis of population-level variation in genetic diversity for 727 plant and animal species finds that biogeography, life history traits and climate are important for predicting the distribution of local genetic diversity, and should be considered together when assessing the local conservation status of species.

Aim Population ecologists often focus on changes in the distribution and abundance of wildlife species, which are useful for trend analyses and status assessments. However, rarely are these responses evaluated simultaneously for a single species, despite their unique contributions to fully assess a species' viability. For example, focusing solely on total abundance can mask important losses in overall distribution within a metapopulation structure that may contribute to long‐term population instability that results from the extirpation of small peripheral populations. Location Bi‐State region of Nevada and California, USA. Methods We simultaneously evaluated changes in population abundance and distribution for greater sage‐grouse (hereafter sage‐grouse; Centrocercus urophasianus) within the Bi‐State Distinct Population Segment (DPS), a genetically distinct and isolated population straddling the border of Nevada and California. We combined population counts, demographic data, and information on space use from marked individuals to evaluate changes in population distribution and abundance over three time periods that corresponded to the three most recent population nadirs (1995–2019, 2002–2019 and 2008–2019). Results The Bi‐State DPS exhibited evidence of 1.2%–2.5% declines annually, over the short/medium‐term (1995–2019; λ̂ λ̂ = 0.987, 95% CRI: 0.970–0.999), short‐term (2002–2019; λ̂ λ̂ = 0.975, 95% CRI: 0.963–0.985) and recent‐term (2008–2019; λ̂ λ̂ = 0.988, 95% CRI: 0.973–1.001). Since 1995, the spatial distribution of sage‐grouse abundance in the Bi‐State DPS shifted amongst subpopulations, with peripheral subpopulations suffering the largest declines. Main Conclusions Gains in abundance and distribution amongst expanding subpopulations did not offset losses in the remaining subpopulations, with a net loss in occupied distribution of 156 km2 since 1995. Reductions in spatial distribution could have implications for metapopulation persistence as peripheral populations become more vulnerable to stochastic events, which would not have been apparent from the evaluation of overall metapopulation abundance on its own.

African elephants are keystone species facing severe declines due to the ivory trade and habitat loss. To investigate the genomic consequences, we analyze 232 high-coverage genomes from 17 African countries in the first continent-wide genomic analysis treating savanna ( Loxodonta africana ) and forest ( L. cyclotis ) elephants as distinct species. We find a deep divergence between species, with forest elephants showing higher heterozygosity and historically larger effective population sizes, while savanna elephants exhibit greater inbreeding and genetic load. Surprisingly, we detect widespread introgression of trace forest ancestry across savanna populations, suggesting a complex history of hybridization. Within species, historically high mobility promoted genetic connectivity, though we identify signs of human-induced isolation and drift in peripheral populations. Our findings highlight gene flow as a key force in African elephant evolution and underscore the urgency of understanding the impact of accelerating habitat fragmentation in these ecosystem engineers. The two species of African elephants are facing severe declines. Here, authors assess their continent-wide genomic diversity, identifying differences in their evolutionary histories and highlighting the formative role of gene flow.