Location Of Refugia Research Articles

Early postglacial recolonisation, refugial dynamics and the origin of a major biodiversity hotspot. A case study from the Malá Fatra mountains, Western Carpathians, Slovakia

While general trends in Central European postglacial recolonisation dynamics are relatively well known, we often lack studies on intermediate (meta-population, landscape) scales. Such studies are needed to increase our understanding of, for example, the location of refugia; emergence of endemism, rates and trajectories of postglacial migrations; and anthropogenic landscape changes. Here, we focused on the outer Western Carpathian mountain chain Malá Fatra, which is currently characterised by high biodiversity and endemism and is thus considered a likely refugium of the Last Glacial period for the temperate biota of Eastern–Central Europe. We used molluscs and vascular plants as reference taxonomic groups and supported palaeoenvironmental interpretations of their (sub)fossil assemblages using high-resolution geochemical data. Generally, postglacial biotic successions from the study region fit the standard developmental pattern well in Middle and Eastern European uplands. Nevertheless, we found important biogeographically based peculiarities. In total, more than 50 species per (sub)fossil community at the reference site Valča, including 30 woodland species and 11 Carpathian endemites, make site of the highest known Holocene mollusc species diversity in Europe. Our palaeoecological analysis of this long-term biodiversity hotspot suggests that the Western Carpathians were likely an important source of the postglacial recolonisation of Central Europe by forest biota and, at the same time, an area of refugium-based endemism.

Hybrid zone formation and contrasting outcomes of secondary contact over transects in common toads.

Much progress in speciation research stems from documenting patterns of morphological and genetic variation in hybrid zones. Contrasting patterns of marker introgression in different sections of the contact can provide valuable insights on the relative importance of various evolutionary mechanisms maintaining species differences in the face of hybridization and gene flow and on hybrid zone temporal and spatial dynamics. We studied species interactions in the common toads Bufo bufo and B.spinosus in France and northwestern Italy using morphological and molecular data from the mitochondrial and nuclear genomes in an extensive survey, including two independent transects west and east of the Alps. At both, we found sharp, coincident and concordant nuclear genetic transitions. However, morphological clines were wider or absent and mtDNA introgression was asymmetric. We discuss alternative, nonexclusive hypotheses about evolutionary processes generating these patterns, including drift, selection, long-distance dispersal and spatial shifts in hybrid zone location and structure. The distribution of intraspecific mtDNA lineages supports a scenario in which B.bufo held a local refugium during the last glacial maximum. Present-day genetic profiles are best explained by an advance of B.spinosus from a nearby Iberian refugium, largely superseding the local B.bufo population, followed by an advance of B.bufo from the Balkans, with prongs north and south of the Alps, driving B.spinosus southwards. A pendulum moving hybrid zone, first northwards and then southwards, explains the wide areas of introgression at either side of the current position of the contact zones.

Population genetics of three sympatric springtail species (Hexapoda: Collembola) from the South Shetland Islands: evidence for a common biogeographic pattern

Three sympatric springtail species, from the South Shetland Islands archipelago in the maritime Antarctic, are analysed here in a common biogeographic and evolutionary framework. This study was designed to compare their population genetic structure using the same molecular marker. Haplotype data for the mitochondrial cox1 gene have been obtained for seven populations of Folsomotoma octooculata and are compared with the data obtained, in previous studies and the current one, for the sympatric species Cryptopygus antarcticus antarcticus, and Friesea grisea. Molecular data obtained are consistent with the hypothesis that all species have been present in the archipelago since well before the last glacial maximum (around 20 000 ybp) and that their early diversifications appear to be linked with known interglacial periods in the region. These springtails may have survived the last glacial cycle in local refugia, from which they dispersed subsequently to ice-free ground re-exposed during the current interglacial period. The populations of the different species diversified at different times, although all of them are within the Pleistocene epoch. We propose that the earliest diversification of haplotypes in all three springtails in this archipelago occurred from local refugia in Livingston I., with subsequent spread of some haplotypes throughout the South Shetland Islands.

Post-glacial colonization of Europe by the wood mouse,Apodemus sylvaticus: evidence of a northern refugium and dispersal with humans

The wood mouse Apodemus sylvaticus is an opportunistic rodent that is found throughout most of the European mainland. It is present on many islands around the margins of the continent and in northern Africa. The species has been the subject of previous phylogeographical studies, although these have focussed on the more southerly part of its range. A substantial number of new samples, many of them from the periphery of the species' range, contribute to an exceptional dataset comprising 981 mitochondrial cytochrome b sequences. These new data provide sufficient resolution to transform our understanding of the survival of the species through the last glaciation and its subsequent re-colonization of the continent. The deepest genetic split that we found is in agreement with previous studies and runs from the Alps to central Ukraine, although we further distinguish two separate lineages in wood mice to the north and west of this line. It is likely that this part of Europe was colonized from two refugia, putatively located in the Iberian peninsula and the Dordogne or Carpathian region. The wood mouse therefore joins the growing number of species with extant populations that appear to have survived the Last Glacial Maximum in northern refugia, rather than solely in traditionally recognized refugial locations in the southern European peninsulas. Furthermore, the existence of a northern refugium for the species was predicted in a study of mitochondrial variation in a specific parasite of the wood mouse, demonstrating the potential value of data from parasites to phylogeographical studies. Lastly, the presence of related haplotypes in widely disparate locations, often on islands or separated by substantial bodies of water, demonstrates the propensity of the wood mouse for accidental human-mediated transport.

Bumble bees of Kanawha County, WV, with statewide trends over the last century.

The goal of our research is to assess the overall diversity of and to evaluate the presence and relative abundance of declining bumble bee species (e.g., Bombus affinis, B. pensylvanicus and B. terricola), in Kanawha County, WV. We collected bees locally from a variety of field sites to establish local population numbers and community structure. Additionally, to determine whether the community structure of bumble bees has changed over time, we compiled museum collection data to calculate community structure data from the last 95 years. Our local data indicated suggested that the bumble bee community of Kanawha County is dominated (~95% of total specimens collected) by three species (B. impatiens, B. bimaculatus and B. griseocollis); a pattern of diversity similar to that found in other regions of North America that have been similarly surveyed. Additionally, our data suggested very weak populations of bumble bees in the subgenera Thoracobombus and Bombus (sensu strictu). Our statewide data indicated that species of bees that are experiencing declines in other parts of North America are also declining in WV and that the bees that are replacing those declining species are predominantly those in the subgenera Pyrobombus and Cullumanobombus.This study undoubtedly contributes to our understanding of the local diversity of these insects, but perhaps more importantly, it will provide valuable data regarding the decline of these pollinators and perhaps provide insights to the locations of refugia where otherwise declining species may occur in higher, sustainable densities.

The effects of drainage and restoration of pine mires on habitat structure, vegetation and ants

Habitat loss and degradation are the main threats to biodiversity worldwide. For example, nearly 80% of peatlands in southern Finland have been drained. There is thus a need to safeguard the remaining pristine mires and to restore degraded ones. Ants play a pivotal role in many ecosystems and like many keystone plant species, shape ecosystem conditions for other biota. The effects of mire restoration and subsequent vegetation succession on ants, however, are poorly understood. We inventoried tree stands, vegetation, water-table level, and ants (with pitfall traps) in nine mires in southern Finland to explore differences in habitats, vegetation and ant assemblages among pristine, drained (30–40 years ago) and recently restored (1–3 years ago) pine mires. We expected that restoring the water-table level by ditch filling and reconstructing sparse tree stands by cuttings will recover mire vegetation and ants. We found predictable responses in habitat structure, floristic composition and ant assemblage structure both to drainage and restoration. However, for mire-specialist ants the results were variable and longer-term monitoring is needed to confirm the success of restoration since these social insects establish perennial colonies with long colony cycles. We conclude that restoring the water-table level and tree stand structure seem to recover the characteristic vegetation and ant assemblages in the short term. This recovery was likely enhanced because drained mires still had both acrotelm and catotelm, and connectedness was still reasonable for mire organisms to recolonize the restored mires either from local refugia or from populations of nearby mires.

Historical and contemporary determinants of global phylogenetic structure in tropical reef fish faunas

Identifying the main determinants of tropical marine biodiversity is essential for devising appropriate conservation measures mitigating the ongoing degradation of coral reef habitats. Based on a gridded distribution database and phylogenetic information, we compared the phylogenetic structure of assemblages for three tropical reef fish families (Labridae: wrasses, Pomacentridae: damselfishes and Chaetodontidae: butterflyfishes) using the net relatedness (NRI) and nearest taxon (NTI) indices. We then related these indices to contemporary and historical environmental conditions of coral reefs using spatial regression analyses. Higher levels of phylogenetic clustering were found for fish assemblages in the Indo‐Australian Archipelago (IAA), and more particularly when considering the NTI index. The phylogenetic structure of the Pomacentridae, and to a lower extent of the Chaeotodontidae and Labridae, was primarily associated with the location of refugia during the Quaternary period. Phylogenetic clustering in the IAA may partly result from vicariance events associated with coral reef fragmentation during the glacial periods of the Quaternary. Variation in the patterns among fish families further suggest that dispersal abilities may have interacted with past habitat availability in shaping the phylogenetic structure of tropical reef fish assemblages.

Persistence, isolation and diversification of a naturally fragmented species in local refugia: the case of Hydromantes strinatii.

The study of the European plethodontid salamander Hydromantes strinatii using allozyme and mitochondrial markers showed a strong geographical genetic structure. This was likely the outcome of different evolutionary mechanisms leaving their signature despite the effects of the genetic drift due to the low population size typical of this species. Two highly divergent clades were identified in the eastern and central-western part of the range, with further geographic sub-structure. Nuclear and mitochondrial markers substantially recovered the same population groups but were conflicting in reconstructing their relationships. This apparent incongruence highlighted the action of different mechanisms such as secondary contacts and incomplete lineage sorting in originating the observed genetic variation. The troglophilic habit of this species provided the opportunity to show the importance of caves as local refugia in maintaining the genetic diversity through the persistence of local populations. Accordingly, high nucleotide and haplotype diversity, strong geographic genetic structuring and lack of expansion were evidenced. This signature was found in the populations from the Ligurian and Maritime Alps, in agreement with the complex orography and paleoclimatic history of this Mediterranean hotspot.

Origin and Genetic Diversity of Lake Trout in the Togiak National Wildlife Refuge, Alaska

AbstractLake trout Salvelinus namaycush is a slow-growing, late-maturing, cold-water-adapted species whose native distribution is described by the glaciated regions of North America. Southwestern Alaska, the western limit of the species range, has undergone repeated episodes of glacial advance and retreat. In this study, lake trout were sampled from 15 lakes in six drainages on or near Togiak National Wildlife Refuge (TNWR) in southwestern Alaska. Data from 14 microsatellite loci were used to test for genetic evidence that lake trout survived the most recent glacial advance in a local refugium, and to test the effect of habitat size, elevation, and drainage on within- and among-population variation. We could not infer that unglaciated lakes within the TNWR served as a refugium during the most recent glacial maximum. In a neighbor-joining tree, populations largely clustered by drainage, suggesting a single founding source for each drainage. An exception occurred in the Nushagak and Kuskokwim rivers, where evidence for stream capture was detected. Among-population variation, as measured by FST, was 0.35; pairwise FST within drainages ranged from 0.05 to 0.47, indicative of low gene flow, even within drainages, though individual-based analysis detected movement of lake trout among lakes within the Kanektok, Goodnews, and Nushagak rivers. Lake surface area was positively associated with allele richness, and negatively associated with FIS, indicating that smaller lakes in the TNWR harbor less genetic diversity and may have more limited adaptive potential.

Evidence for cryptic northern refugia in the last glacial period in Cryptomeria japonica.

Distribution shifts and natural selection during past climatic changes are important factors in determining the genetic structure of forest species. In particular, climatic fluctuations during the Quaternary appear to have caused changes in the distribution ranges of plants, and thus strongly affected their genetic structure. This study was undertaken to identify the responses of the conifer Cryptomeria japonica, endemic to the Japanese Archipelago, to past climatic changes using a combination of phylogeography and species distribution modelling (SDM) methods. Specifically, this study focused on the locations of refugia during the last glacial maximum (LGM). Genetic diversity and structure were examined using 20 microsatellite markers in 37 populations of C. japonica. The locations of glacial refugia were assessed using STRUCTURE analysis, and potential habitats under current and past climate conditions were predicted using SDM. The process of genetic divergence was also examined using the approximate Bayesian computation procedure (ABC) in DIY ABC to test the divergence time between the gene pools detected by the STRUCTURE analysis. STRUCTURE analysis identified four gene pools: northern Tohoku district; from Chubu to Chugoku district; from Tohoku to Shikoku district on the Pacific Ocean side of the Archipelago; and Yakushima Island. DIY ABC analysis indicated that the four gene pools diverged at the same time before the LGM. SDM also indicated potential northern cryptic refugia. The combined evidence from microsatellites and SDM clearly indicates that climatic changes have shaped the genetic structure of C. japonica. The gene pool detected in northern Tohoku district is likely to have been established by cryptic northern refugia on the coast of the Japan Sea to the west of the Archipelago. The gene pool in Yakushima Island can probably be explained simply by long-term isolation from the other gene pools since the LGM. These results are supported by those of SDM and the predicted divergence time determined using ABC analysis.

Demography linked to climate change projections in an ecoregional case study: integrating forecasts and field data

Anticipating species movement under climate change is a fundamental concern in 21st century conservation. For blue oak (Quercus douglasii), an endemic, flagship species in California, we modeled potential responses to future climate, then tested the fit of those projections to empirical field data from natural populations. Specifically, we tested how well species forecasts captured observed recruitment and adult tree mortality, and whether recruitment was structured spatially as a function of fine‐scale micro‐topographic and hydrologic environments. In this ecoregional case study, observed demographic patterns were broadly consistent with theoretical expectations. Adult survivorship was three times lower in areas forecasted to be least suitable as a result of climate change than in areas projected to become suitable. This novel field validation exercise documents patterns of adult tree mortality consistent with model predictions of an emergent shift in distribution. Seedlings and saplings showed evidence of spatial structuring into local refugia in areas projected to contract, suggesting that climate change may reshape how blue oak associates with California landscapes and highlighting the potential importance of micro‐environmental diversity in enhancing species resilience to warming.

Spatial structure in European moose (Alces alces): genetic data reveal a complex population history

AbstractAimMoose, Alces alces (Linnaeus, 1758), survived the European Pleistocene glaciations in multiple southern refugia, in a northern refugium near the Carpathians and possibly in other locations. During the second millennium ad, moose were nearly extirpated in Europe and only recolonized their current range after World War II. The number and location of refugia during the Pleistocene and recent population lows may have affected the current genetic diversity. We sought to characterize the genetic diversity in European moose in order to determine its genetic structure and the location of genetic hotspots as a way of inferring its population history and the number of Last Glacial Maximum (LGM) refugia.LocationEurope.MethodsWe sequenced 538 nucleotides from the mitochondrial control region of 657 moose from throughout the species' European range. We estimated diversity within and among 16 sampling localities, and used samova to cluster sampling locations into subpopulations. We constructed phylogenetic trees and median‐joining networks to examine systematic relationships, and conducted Bayesian analysis of the coalescent and used mismatch distributions and approximate Bayesian computation to infer demographic history.ResultsEstonia had the highest nucleotide diversity, and western Belarus had the highest haplotype diversity. We observed four regional populations from the samova analysis. We found three haplogroups in European moose, probably representing lineages conserved in different refugia during the Pleistocene. European moose underwent spatial expansion after the LGM, but did not undergo demographic expansion. The effective population size has declined markedly within the last 2000 years.Main conclusionsThe current levels and distribution of genetic diversity in European moose indicate the effects both of Pleistocene glaciations and of a recent bottleneck, probably associated with anthropogenic influences such as pastoralization and hunting, and a very recent re‐expansion. We show that both historical and recent events can influence the diversity and distribution of a large mammal on a large scale.

Revisiting the phylogeography and demography of European badgers (Meles meles) based on broad sampling, multiple markers and simulations.

Although the phylogeography of European mammals has been extensively investigated since the 1990s, many studies were limited in terms of sampling distribution, the number of molecular markers used and the analytical techniques employed, frequently leading to incomplete postglacial recolonisation scenarios. The broad-scale genetic structure of the European badger (Meles meles) is of interest as it may result from historic restriction to glacial refugia and/or recent anthropogenic impact. However, previous studies were based mostly on samples from western Europe, making it difficult to draw robust conclusions about the location of refugia, patterns of postglacial expansion and recent demography. In the present study, continent-wide sampling and analyses with multiple markers provided evidence for two glacial refugia (Iberia and southeast Europe) that contributed to the genetic variation observed in badgers in Europe today. Approximate Bayesian computation provided support for a colonisation of Scandinavia from both Iberian and southeastern refugia. In the whole of Europe, we observed a decline in genetic diversity with increasing latitude, suggesting that the reduced diversity in the peripheral populations resulted from a postglacial expansion processes. Although MSVAR v.1.3 also provided evidence for recent genetic bottlenecks in some of these peripheral populations, the simulations performed to estimate the method's power to correctly infer the past demography of our empirical populations suggested that the timing and severity of bottlenecks could not be established with certainty. We urge caution against trying to relate demographic declines inferred using MSVAR with particular historic or climatological events.

Precipitation rather than temperature influenced the phylogeography of the endemic shrub Anarthrophyllum desideratum in the Patagonian steppe

AbstractAimIn order to assess the impact of precipitation changes during Pleistocene glaciations on plant species of the Patagonian steppe, a phylogeographical study of the endemic shrub Anarthrophyllum desideratum was performed.LocationSouthern Patagonia: Argentina and Chile.MethodsChloroplast intergenic spacers trnS–trnG and rpoB–trnC were sequenced for 264 individuals from 33 localities spanning the entire distribution of A. desideratum. Phylogenetic (statistical parsimony, maximum likelihood and Bayesian inference) and population genetic analyses (spatial analyses of molecular variance, mismatch distributions, neutrality tests and Bayesian skyline plot) were performed. Divergence time estimates using a calibrated molecular clock were also conducted. Niche modelling was used to reconstruct the palaeodistribution to validate phylogeographical patterns.ResultsThirty haplotypes were identified that clustered into two main lineages, revealing a significant latitudinal phylogeographical break north and south of the Deseado River (c. 47° S). Infra‐specific diversification began in the late Miocene, with northern and southern lineages separating c. 3 Ma, after the eastern Patagonian lowlands started to become increasingly arid. Three areas of high molecular diversity were identified: one in southern and two in northern Patagonia where niche modelling indicates that the species may have survived during the Last Glacial Maximum. These putative refugia received more moisture than much of the steppe during glaciation‐associated aridization. The south‐western refugium is the more likely source for eastward range expansion during post‐glacial humidification.Main conclusionsAnarthrophyllum desideratum responded differently to historical processes north and south of the Deseado River. In the north this species survived in situ in fragmented populations, whereas in the south it survived in localized refugia that presumably avoided extreme aridization, and from which it expanded eastwards. For southern Patagonia, our results support a new historical scenario affected more by precipitation regimes than by temperature changes associated with glacial cycles. This hypothesis should be considered in future plant phylogeographical studies from the Patagonian steppe.

Buxus in Europe: Late Quaternary dynamics and modern vulnerability

Abstract The suggested location of broadleaved evergreen trees in Europe during the last full-glacial has traditionally favoured a southerly refugial model, which proposes survival in the Mediterranean peninsulas and recolonization of central and northern Europe during the Holocene. This hypothesis is not always substantiated by thorough reviews of original past and modern occurrence data, or considered in the light of plant traits and autoecology. Our approach focuses on the genus Buxus with the aim of exploring (i) the relationship between the location of refugia and post-glacial population dynamics, (ii) past processes determining density, fragmentation and local extinctions of modern populations, and (iii) the vulnerability of Buxus in the context of the undergoing environmental changes. We compiled a database of over 3600 modern occurrences and 676 fossil sites to reconstruct the distribution of Buxus in Europe since 30 ka cal BP. The location of fossil finds and the plant traits of Buxus indicate that it persisted widely across its modern distribution through the last glacial period with modes varying from region to region. The E Pyrenees, W Alps, and Jura Mts hosted dense populations, which expanded exponentially during the whole Holocene, and resulted in a modern continuous distribution area. In contrast, the Mediterranean Peninsulas hosted sparse populations, which increased exponentially only during the first half of the Holocene, clearly decreased in the last 4.5 ka BP and resulted in a highly fragmented modern distribution area, most likely in relation to the climate trends towards dry conditions of the last few millennia. These results challenge the common view that the Mediterranean regions are the exclusive and most important refuge areas for evergreen broadleaved trees and stress the importance of considering long-term population dynamics based on fossil data to evaluate the vulnerability of modern fragmented plant populations in view of conservation actions.

Genetically diverse but with surprisingly little geographical structure: the complex history of the widespread herb Carex nigra (Cyperaceae)

AbstractAim Based on extensive range‐wide sampling, we address the phylogeographical history of one of the most widespread and taxonomically complex sedges in Europe, Carex nigra s. lat. We compare the genetic structure of the recently colonized northern areas (front edge) and the long‐standing southern areas (rear edge), and assess the potential genetic basis of suggested taxonomic divisions at the rank of species and below.Location Amphi‐Atlantic, central and northern Europe, circum‐Mediterranean mountain ranges, central Siberia, Himalayas.Methods A total of 469 individuals sampled from 83 populations, covering most of the species’ range, were analysed with amplified fragment length polymorphism (AFLP) and chloroplast DNA (cpDNA) markers. Bayesian clustering, principal coordinates analysis, and estimates of diversity and differentiation were used for the analysis of AFLP data. CpDNA data were analysed with statistical parsimony networks and maximum parsimony and Bayesian inference of phylogenetic trees.Results Overall genetic diversity was high, but differentiation among populations was limited. Major glacial refugia were inferred in the Mediterranean Basin and in western Russia; in addition, there may have been minor refugia in the North Atlantic region. In the southern part of the range, we found high levels, but geographically quite poorly structured genetic diversity, whereas the levels of genetic diversity varied among different areas in the north. North American populations were genetically very similar to the European populations.Main conclusions The data are consistent with extensive gene flow, which has obscured the recent history of the taxon. The limited differentiation in the south probably results from the mixing of lineages expanding from several local refugia. Northward post‐glacial colonization resulted in a leading‐edge pattern of low diversity in the Netherlands, Belgium, Scotland and Iceland, whereas the observed high diversity levels in Fennoscandia suggest broad‐fronted colonization from the south as well as from the east. The patterns found in the American populations are consistent with post‐glacial colonization, possibly even with anthropogenic introduction from Europe. Our data also suggest that the tussock‐forming populations of C. nigra, often referred to as a distinct species (Carex juncella), represent an ecotype that has originated repeatedly from different populations with creeping rhizomes.

Environmental context of the Magdalenian settlement in the Jura Mountains using stable isotope tracking (13C, 15N, 34S) of bone collagen from reindeer (Rangifer tarandus)

The Jura Mountains are considered to be a region where phases of ice cap extension and retreat in response to climatic variation during the Upper Pleniglacial and Lateglacial (ca. 24,000–12,800 cal BP) are well reflected in the vegetation and animal spectrum composition. A new set of direct AMS radiocarbon dates of collagen from reindeer (Rangifer tarandus) bones found at archaeological sites indicated an almost continuous occupation of the Jura region since the end of Last Glacial Maximum, at ca. 24,000 cal BP, until its local disappearance around 14,000 cal BP. To investigate a possible change in reindeer ecology, isotopic analysis of carbon, nitrogen, sulfur in collagen (δ13Ccoll, δ15Ncoll, δ34Scoll) were performed on the dated specimens. A decrease in the δ13Ccoll and δ15Ncoll values of Jura reindeer was found at the beginning of the Lateglacial period around 16,300–15,600 cal BP. While the change in δ13Ccoll values was better explained by a change in diet composition with a decreasing input of lichens, the relative low δ15Ncoll values of the reindeer during the Lateglacial was consistent with a geographical pattern of soil maturity inherited from the Last Glacial Maximum. The same pattern was also seen in the δ15Ncoll values of the Lateglacial horse (Equus sp.) and red deer (Cervus elaphus) until ca. 14,000 cal BP. The decrease in reindeer δ15Ncoll around 16,300–15,600 cal BP and around 21,000–20,000 cal BP in the Jura region may be linked to the occupation of territories recently released by glaciers that formed during the Heinrich event 1 and the Last Glacial Maximum, respectively. The associated high δ15Ncoll and δ34Scoll values found in two specimens indicate the occurrence of areas of high soil activity in a globally cold context. This might correspond to the occupation of refugia in the close surroundings of the Jura region. Such local refugia could explain the capacity of the reindeer to occupy rapidly the newly available territories during phase of glacier retreat. The intensification of the Magdalenian human settlement could have been favored by these local ecosystem expansions.

Extensive range persistence in peripheral and interior refugia characterizes Pleistocene range dynamics in a widespread Alpine plant species (Senecio carniolicus, Asteraceae)

Recent evidence suggests that survival of arctic-alpine organisms in peripheral or interior glacial refugia are not mutually exclusive and may both be involved in shaping an organism’s Pleistocene history, yet potentially at different time levels. Here, we test this hypothesis in a high-mountain plant (diploid lineage of Senecio carniolicus, Asteraceae) from the Eastern European Alps, in which patterns of morphological variation and current habitat requirements suggest survival in both types of refugia. To this end, we used AFLPs, nuclear and plastid DNA sequences and analysed them, among others, within a graph theoretic framework and using novel Bayesian methods of phylogeographic inference. On the basis of patterns of genetic diversity, occurrence of rare markers, distribution of distinct genetic lineages and patterns of range connectivity both interior refugia in the formerly strongly glaciated central Alps and peripheral refugia along the southern margin of the Alps were identified. The presence of refugia congruently inferred by markers resolving at different time levels suggests that these refugia acted as such throughout several glacial cycles. The high degree of range persistence together with gradual range expansion, which contrasts with the extent of range shifts implied for other Alpine species, is likely responsible for incipient lineage differentiation evident from the genetic data. Replacing a simplistic peripheral vs. interior refugia dualism by more complex models involving both types of refugia and considering different time levels will help identifying common phylogeographic patterns with respect to, for instance, location of refugia and colonization routes and elucidating their underlying genetic and/or ecological causes.

AN EVALUATION OF LOCAL AND REGIONAL DIVERSITY OF BENTHIC MACROINVERTEBRATE COMMUNITIES IN TWO SMALL REGIONS OF IRELAND AND THEIR POTENTIAL AS LOCALISED REFUGIA FOR CERTAIN TAXONOMIC GROUPS

The objective of this study was to evaluate the taxonomic diversity of freshwater benthic macroinvertebrate communities in two small geographical regions of Ireland and assess their potential as critical refugia for local recolonisation in the future. Areas were identified from previous studies as potentially supporting a high diversity of aquatic macroinvertebrates. Six rivers in the Slieve Bloom Mountains and five rivers in the Killarney region of County Kerry were sampled. Where possible, each river was sampled at intervals along its course at source, 2.5km, 5km and 10km. The local and regional taxonomic richness and β-diversity were assessed at all sites. The results showed that both regions have many healthy freshwater systems and a high occurrence of selected Irish benthic macroinvertebrate species. The local richness and diversity was found to be low, with a high heterogeneity among sites sampled. The regional richness and diversity was high, however, indicating the importance of both regions for benthic macroinvertebrate diversity in Ireland and their potential to act as local refugia in the future. The protection of these regions may be extremely important in providing refuge populations in the future from which surrounding areas can be re-populated, facilitating ecological recovery as required by the Water Framework Directive.

Continuous 300,000-year fossil record: changes in the ornithofauna of Biśnik Cave, Poland

Biśnik Cave is situated in a limestone rock about 50 km northeast of Krakow, southern Poland. Its importance stems from the fact that it is one of the few sites in Europe, and the only one in Poland, with 300,000-year-long sequence of uninterrupted sediments, that cover the time span from before the Saalian to the Holocene. The excavations yielded about 200,000 animal bones and more than 4,000 stone, bone and antler artifacts. Bird remains from Biśnik Cave consist of nearly 1,600 skeletal fragments of at least 96 taxa that represent a minimum of 285 individuals. The majority of the remains belong to Galliformes; relatively numerous are also Corvidae, Falconiformes, Anseriformes and the genus Turdus. The remains include one extinct taxon (Falco tinnunculus atavus) and four species new for the Polish fossil avifauna (Aquila heliaca, Pinicola enucleator, Loxia pytyopsittacus and Carduelis flammea). Avian remains indicate a mosaic of various habitats in the surroundings of Biśnik Cave. Some kind of mature forest or at least sparsely growing trees, as well as water bodies, marshes, wet meadows, steppe and tundra habitats must have been present during the entire time of sedimentation. It is postulated that the Krakow-Czestochowa Upland was a local refugium for the forest fauna during the Saalian and Vistulian glaciations.