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Aim To determine the interplay between climate and land use changes in driving population dynamics in a butterfly species, Coenonympha hero, at the southern limit of its distribution. Location French Jura massif and Europe. Methods We analysed patterns of genetic diversity distribution at 817 loci in 136 butterflies from 31 sites using NGS to infer the genetic structure and population size changes over time, using two methods of demographic inference (SNP frequency spectrum analyses and coalescent ABC inferences). We then characterized the climate and land use descriptors of C. hero geographic distribution using species distribution modelling (SDM) and ordination method and compared demographic changes to changes in climatically suitable areas. Results Coenonympha hero persists in the Jura massif as three core populations that share a common history of decline in two steps: an old decline and a more recent decline that resulted in population fragmentation, the southernmost sites being the most threatened (lowest genetic diversity). Climate change during the Würm glaciation is presumably the main factor explaining the first demographic decline. The second decline started 2000 years ago possibly under increased human pressure as suggested by recent extinctions in several sites nowadays characterized by urban and agricultural surfaces. Both climate and land use variables are important descriptors of C. hero distribution, as SDM predictions were improved by adding aridity index, altitude and land use to bioclimatic predictors. Its habitats include forests in north‐eastern Europe and grasslands in the Jura massif. Main conclusions Using SDM and genetic demographic inferences, we identified a persistent glacial refuge for the species in Europe. We show that although this relictual population has declined and fragmented under the combined effects of climate warming and anthropization, the metapopulation is still functional but requires particular conservation attention to maintain its connectivity, and to favour the local persistence of this highly endangered butterfly species.

Aim To assess the origin and genetic relationship of the northernmost population of Rhododendron ferrugineum in the Karkonosze Mts. (the Sudetes), located 350 km north of the previously acknowledged species limit, in the context of the whole species range; to discuss, based on this case study, the glacial history of the Central European mountain flora and importance of rare, relict populations for biogeographical inference and diversity conservation. Location European mountains: Sudetes, Alps, Pyrenees. Methods We sampled 90 individuals from 26 R. ferrugineum populations spanning the whole species’ range. To infer genetic structure, diversity and relationships among populations and isolated parts of the geographical range, we applied genome‐wide amplified fragment length polymorphism (AFLP) genotyping and sequencing of four cpDNA fragments and nrDNA ITS region. Results Our AFLP analysis revealed four distinct genetic groups in R. ferrugineum, one formed by the northernmost population from (a) the Karkonosze Mts. (the Sudetes) and the other three comprising populations from the (b) Western Alps and Pyrenees, (c) South‐Westernmost Alps and (d) Eastern Alps. Genetic isolation of the Karkonosze population was further corroborated by a repetitive pattern differentiation in plastid DNA sequences, otherwise almost monomorphic across the range. Population from the Karkonosze was most closely related to those from the Western Alps and not from the geographically closest Eastern Alps. Main conclusions We show that the population of R. ferrugineum in the Karkonosze Mts. is a glacial relict and not a recently established or introduced population. Its distinctiveness and high genetic diversity show that it represents a northern, previously undetected, genetic lineage of the species in Europe, which persisted through climatic changes in a small but stable microrefugium. Our case study highlights the importance of an adequate coverage of a species’ range in phylogeographical studies and the significance of peripheral parts of the range to reveal biogeographical history of lineages. It also supports the Karkonosze Mountains as an important refugium for the Central European mountain flora.

Central European peatlands are important biodiversity hotspots and potential climate‐change refugia, preserving post‐glacial relict species and offering insights into long‐term ecological functioning. Despite pressures from climate change and land‐use disturbances, some relict populations persist even in degraded sites, with genetic studies revealing both their diversity and growing vulnerability to isolation. This paper highlights the importance of understanding the mechanisms underpinning the climate‐change refugia potential of a peatland, particularly the role of microclimatic conditions. Integrating paleoecological, ecological, and biogeographical perspectives is key to safeguarding peatlands' role in biodiversity conservation and climate regulation. Some peatlands in Central Europe serve as continuous refugia for glacial species, as shown by paleoecological data. However, the ecosystem mechanisms behind this are not well understood. Microclimate plays a key role, and understanding the factors shaping it is crucial for managing peatlands as climate‐change refugia. This paper highlights key issues that require further research.

Small, isolated populations are more vulnerable to natural disturbances and loss of genetic diversity. Scots pine, an abundant tree species in the boreal forest of Eurasia, has a scattered natural distribution across Eastern and Southern Carpathian Mountains, where only a few relict populations still exist. We estimated genetic diversity and spatial genetic structure in Scots pine on the basis of microsatellite nuclear markers (nSSR) data. We found a relatively high level of genetic diversity (He = 0.697) within populations and no evidence of recent bottlenecks. Genetic diversity was lower in peat bog populations, as compared to populations that grow on rocky slopes or acidic soils and nutrient-poor sites. Population genetic structure was weak, and genetic discontinuities among populations were detected. Spatial genetic structure (SGS) was observed in nearly all Scots pine populations. The strength of SGS, quantified by Sp statistics, varied greatly among populations, ranging from 0.0011 to 0.0207, with an average of 0.01. Our study highlights that Eastern and Southern Carpathian populations still possess high within-population diversity in spite of the recent fragmentation and reduction of the Scots pine natural distribution range. We discuss the importance of spatial patterns of genetic diversity for developing strategies of conservation and sustainable use of Scots pine genetic resources in the Carpathian region.

The Southern smooth snake, Coronella girondica, is a small-sized colubrid found in Northwest Africa and Southwest Europe. Mitochondrial DNA-based studies showed that the species can be split into five clades: two from Northwest Africa (one Moroccan and one Tunisian-Algerian) and three from Europe (one in the south-west of the Iberian Peninsula, one in the south-east of Spain and one in the rest of the European range). With regards to Italy, to date, only two samples have been analysed both from the Province of Pisa, Tuscany, pointing at that fact that genetic characterisation of Italian populations is still lacking. Accordingly, we have increased the sampling coverage with 19 new samples from northern and central regions of Italy, including two populations, apparently disconnected from the rest of the known range, and analysed their phylogenetic relationships using a portion of the mitochondrial cytochrome b gene. Our results confirm the general phylogenetic arrangement detected in previous studies; specifically for Italian populations, no variability emerged from the Apennine populations, and a slight differentiation could be shown for the Alpine and subalpine ones. This pattern can be explained assuming past spread and recent isolation of C. girondica relict populations in the Alpine region, likely during the Last Glacial Maximum. Later, during the Holocene, the Italian Alps and the Po Plain went through various climatic variations and high anthropization which may have influenced C. girondica distribution through expansion and contraction processes.

Water availability is a major constraint on socioeconomic development in northeastern Mexico, highlighting the need for effective water resource planning that accounts for the variability and extremes of precipitation. In this study, seasonal precipitation reconstructions were developed using tree-ring chronologies from spruce species (Picea spp.). A representative chronology for Picea mexicana Martínez was developed from two populations and spans the period 1786–2020, while a chronology for Picea martinezii T.F. Patterson was established from three populations covering 1746–2020. Both species exhibited significant positive correlations with January–May precipitation (r = 0.65 and 0.71, respectively; p < 0.01) and negative correlations with maximum temperature over the same period (r = −0.52 and −0.59, respectively). Two January–May precipitation reconstructions were produced for periods with adequate sample depth (EPS > 0.85): 1851–2020 for P. mexicana and 1821–2020 for P. martinezii. Both reconstructions revealed pronounced interannual variability, with recurrent droughts and persistently dry conditions, particularly evident in the P. mexicana series. Spatial correlation analyses indicated a historical link between reconstructed precipitation and the El Niño–Southern Oscillation (ENSO). These results highlight the value of spruce species for dendroclimatic reconstruction and their sensitivity to precipitation variability, especially as rising maximum temperatures may compromise their persistence in the Sierra Madre Oriental.

Aim: In deserts, past climate change (and particularly past rainfall variability) plays a large role in explaining current plant species distributions. We ask which species were most and which were least affected by changes in rainfall during the late Quaternary in northernmost Chile. Location: Quebrada La Higuera (QLH; 18° S), a shallow canyon that cuts east-west through the western Andean precordillera of northern Chile, connecting the Altipiano with the hyperarid Atacama Desert. Methods: We collected and dated 22 rodent middens from elevations of 3100-3500 m in QLH. These were analysed for identifiable plant macrofossils and pollen. We also measured chinchilla rat (Abrocoma cinerea) faecal pellets in the youngest middens to explore how they relate to past ecological and climatic change. Results: The three oldest middens dated to more than 37 ka (thousand calibrated ¹⁴C years), four middens dated to 14.4-11.6 ka, and fifteen middens spanned the last 650 years. During all the intervals examined, extralocal species (those found today at higher elevations and indicative of positive rainfall anomalies) were present at our midden sites. In the youngest interval, Parastrephia pollen (indicating increased rainfall) increased abruptly at AD 1760 and remained high until the mid-1800s. This increase was also seen in our faecal pellet record. Main conclusions: Extralocal species were prevalent in late Pleistocene middens at lower elevations when the climate was wetter. When combined with other regional midden records, we postulate that many species found today in the Altipiano were displaced to lower elevations during the late Pleistocene. The recent large-scale mortality documented among arboreal cactus populations along the present upper margins of the Atacama suggests that these are relict populations that are likely to have flourished during a wetter period in the early 1800s.

Scots pine is one of the dominant conifer species in forest ecosystems of the boreal zone in Eurasia. Knowledge of the genetic structure and the level of genetic variability of Scots pine populations is relevant for the development of measures aimed at conservation of species’ diversity. In this study, we used ten paternally inherited chloroplast microsatellite loci to investigate the genetic diversity of nineteen Scots pine populations from Middle Siberia and the Romanian Carpathians. The results of the study showed high genetic diversity (HCP = 0.91–1.00) in all of the investigated populations. The cpSSR analysis yielded a total of 158 haplotypes. The majority of the haplotypes (85%) were detected only once (unique haplotypes). Three common haplotypes were found between the Carpathian and the Siberian populations of Scots pine. Analysis of molecular variance (AMOVA) showed that only 3% of the variation occurred among populations from Middle Siberia and 6% of the variation existed among populations from the Carpathian Mountains. Overall, we found a weak geographic population structure in Scots pine from Middle Siberia and the Romanian Carpathians. The present study on genetic diversity in the Siberian and the Carpathian populations of Scots pine may contribute to the sustainable management and conservation of Scots pine genetic resources in Middle Siberia and the Romanian Carpathians.

Understanding the patterns and processes driving population structure is crucial for conservation planning . Spatial conservation units (CUs) for one or more species have been defined using similarities in communities, habitats, and resource management concerns. Additionally, CU boundaries can be informed by population genetic structure. Here, we determined the population structure of the Bobolink ( Dolichonyx oryzivorus ), a migratory grassland bird. Its breeding range spans longitudinally across most of North America in the northern U.S. and southern Canada, and its population has declined by 59% from 1971 to 2014. We sampled blood from Bobolinks at seven breeding sites and used a ddRAD sequencing approach to identify 3236 SNPs for population genetic analyses. Using the Bayesian clustering approach, STRUCTURE, we found low levels of genetic differentiation across the breeding range. F st values ranged from 0.002 to 0.036 among all population pairs, and genetic structure followed an isolation by distance model. Despite low levels of genetic differentiation, we found evidence for four genetic groupings—breeding populations in Oregon and British Columbia were distinct from each other as well as from Central and eastern North American breeding populations. Investigating the demographic history of the populations using approximate Bayesian computation, we found evidence that western Bobolink populations are not relict populations but instead were founded during a recent westward range expansion, possibly enabled by agricultural expansion. We identify four genetics-based CUs that may serve as a complementary spatial framework, broader in scale compared to the commonly-used Bird Conservation Regions, for defining and achieving population objectives.

We investigate patterns of genetic variation along an east–west transect of Central European populations of Linum flavum and interpret the Quaternary history of its peripheral populations, especially those at the westernmost isolated range edge, discussing their migrations and possible relict status. We defined our peripheral transect across three study regions from Central Hungary, eastern Austria to southwestern Germany. Using AFLP fingerprinting and cpDNA sequence variation (rpL16 intron, atpI‐H), we analyzed 267 and 95 individuals, respectively, representing each study region by four populations. Hierarchical AMOVA (AFLPs) indicated significant variation among study regions (12% of total variance) and moderate differentiation between populations (10%). Population differentiation was high at the westernmost range edge (11.5%, Germany), but also in the east (13.4%, Hungary), compared to the Austrian study region (8.6%). Correspondingly, AFLP diversity was highest in the center of the study transect in eastern Austria. CpDNA haplotypes support a pattern of regional structuring with the strongest separation of the westernmost range edge, and some haplotype sharing among Austrian and Hungarian individuals. Equilibrating nucleotide versus haplotype diversity patterns, the highly diverse populations at the Pannonian range edge (Austria) indicate long‐term persistence, while Central Pannonian populations are obviously effected by recent bottlenecks. Intermediate nucleotide, but high haplotype diversity within the westernmost exclave (Swabian Alb), is indicative of a founder bottleneck during its pre‐LGM or early postglacial migration history, followed by sufficient time to accumulate cpDNA variation. The not obviously reduced genetic diversity and distinctiveness of L. flavum at the westernmost range edge suggest a long‐term persistence (relict status) of populations in this region, where the species has survived probably even the Würm glaciation in extra‐Mediterranean refugia. This genetic relict variation represents an important part of the overall genetic diversity found in the western periphery of this steppe plant and highlights the high conservation priority of respective gene pools. Investigating patterns of genetic variation along an east–west transect of Central European populations of Linum flavum, we interpret the Quaternary history of its peripheral populations, especially those at the westernmost isolated range edge. No obviously reduced genetic diversity and the distinctiveness of the westernmost populations suggest a long‐term persistence in this region, where the species has survived probably even the Würm glaciation in extra‐Mediterranean refugia. This genetic relict variation represents an important part of the overall genetic diversity found in the western periphery of this steppe plant and highlights the high conservation priority of respective gene pools.