Landscape genetics of a recent population extirpation in a burnet moth species

The intensification of agricultural land use over wide parts of Europe has led to the decline of semi-natural habitats, such as extensively used meadows, with those that remain often being small and isolated. These rapid changes in land use during recent decades have strongly affected populations inhabiting these ecosystems. Increasing habitat deterioration and declining permeability of the surrounding landscape matrix disrupt the gene flow within metapopulations. The burnet moth species Zygaena loti has suffered strongly from recent habitat fragmentation, as reflected by its declining abundance. We have studied its population genetic structure and found a high level of genetic diversity in some of the populations analysed, while others display low genetic diversity and a lack of heterozygosity. Zygaena loti was formerly highly abundant in meadows and along the skirts of forests. However, the species is currently restricted to isolated habitat remnants, which is reflected by the high genetic divergence among populations (F _ST: 0.136). Species distribution modelling as well as the spatial examination of panmictic clusters within the study area strongly support a scattered population structure for this species. We suggest that populations with a high level of genetic diversity still represent the former genetic structure of interconnected populations, while populations with low numbers of alleles, high F _IS values, and a lack of heterozygosity display the negative effects of reduced interconnectivity. A continuous exchange of individuals is necessary to maintain high genetic variability. Based on these results, we draw the general conclusion that more common taxa with originally large population networks and high genetic diversity suffer stronger from sudden habitat fragmentation than highly specialised species with lower genetic diversity which have persisted in isolated patches for long periods of time.     

Three ways of assessing metapopulation structure in the butterfly Plebejus argus

1. Three independent methods were used to investigate population structure in the butterfly Plebejus argus . First, migration and dispersal ability were measured by mark–release–recapture in seven adjacent habitat patches, and by release of butterflies in unoccupied habitat. Secondly, colonization of newly created habitat was observed over 7 years. Finally, genetic differentiation of local populations within a metapopulation was investigated. Sampled local populations included parts of the mark–release–recapture study area.
2. Plebejus argus is relatively sedentary: the maximum movement detected was 395 m, and only 2% of individuals moved further than 100 m between recaptures on different days. None the less, adjacent local populations in the mark–release–recapture study area were linked by occasional migration, with ≈ 1.4% of individuals moving between patches separated by 13–200 m.
3. Despite low mobility, observed colonizations occurred rapidly over distances of 1 km. Because P. argus occurs at high population densities, 1.4% migration can generate enough migrants to colonize newly suitable habitat quickly at this spatial scale.
4. Mark–release–recapture data were used to predict that there would be limited genetic differentiation through drift between local populations at this spatial scale. The prediction was supported by allele frequency data for the same local populations.
5. Genetic differentiation often indicates higher levels of migration than are revealed by the movements of marked individuals. This study shows that when experimental releases and extensive marking are undertaken in areas that are large relative to most movements, indirect measures of gene flow and direct measures of dispersal can concur.
6. Evidence from the three different approaches was complementary, indicating that P. argus occurs as metapopulations within the study area.     

Low genetic diversity of a high mountain burnet moth species in the Pyrenees

The burnet moth Zygaena anthyllidis, endemic to the high elevations of the Pyrenees, is vulnerable to land-use. In order to identify conservation priorities based on an assessment of genetic diversity within populations and gene flow among populations, we examined Z. anthyllidis’ genetic variability and differentiation based on allozyme electrophoresis from seven populations scattered across its entire range. In comparison to other mountain Lepidoptera, the populations studied exhibit a low level of genetic diversity. Remarkable between-population differentiation (F _ST = 0.053), the presence of private alleles, and the lack of significant isolation-by-distance pattern characterises the genetic make-up of the species. We interpreted the pattern of genetic differentiation as a consequence of low dispersal power in combination with insufficient landscape connectivity. Ongoing land-use change might reinforce genetic differentiation due to habitat fragmentation and additionally affect negatively allozyme variability at shifting range margins, i.e. the capacity to adapt to changing environments. We therefore suggest creating a network of suitable habitats at the landscape scale to facilitate genetic exchange and to conserve the species’ overall genetic variability.     

Post-glacial history of Trillium grandiflorum (Melanthiaceae) in eastern North America: inferences from phylogeography

Dispersal and migration are important processes affecting the evolutionary history and genetics of species. Here we investigate post-glacial migration and gene flow in Trillium grandiflorum (Melanthiaceae), a wide-ranging, forest herb from eastern North America. Using phylogeographic approaches, we examined cpDNA and allozyme diversity in 35 populations of T. grandiflorum sampled from throughout the geographic range of the species. Nested clade analysis (NCA) of cpDNA haplotypes indicated that T. grandiflorum likely survived in two refugia in the southeastern US during the last glaciation and that long-distance dispersal characterized the post-glacial recolonization of northern areas. There was no evidence for reduced allozyme diversity in populations from glaciated compared to ice-free regions, probably because of the greater abundance and larger effective size of populations in the north. An analysis of isolation-by-distance based on the allozyme data suggested a pattern of population differentiation consistent with restricted gene flow. Notwithstanding the significance of rare seed dispersal events for migration, a comparison of allozyme and cpDNA genetic structure indicates that pollen flow between populations is more likely than seed dispersal. These results for T. grandiflorum represent the first phylogeographic analysis of a temperate woodland herb in eastern North America and support the importance of occasional long-distance dispersal events in the post-glacial migration of plants.     

Strongly diverging population genetic patterns of three skipper species: the role of habitat fragmentation and dispersal ability

The fragmentation of landscapes has an important impact on the conservation of biodiversity, and the genetic diversity is an important factor for a populations viability, influenced by the landscape structure. However, different species with differing ecological demands react rather different on the same landscape pattern. To address this feature, we studied three skipper species with differing habitat requirements (Lulworth Skipper Thymelicus acteon: a habitat specialist with low dispersal ability, Small Skipper Thymelicus sylvestris: a habitat generalist with low dispersal ability, Essex Skipper Thymelicus lineola: a habitat generalist with higher dispersal ability). We analysed 18 allozyme loci for 1,063 individuals in our western German study region with adjoining areas in Luxembourg and north-eastern France. The genetic diversity of all three species were intermediate in comparison with other butterfly species. The F _ST was relatively high for T. acteon (5.1%), low for T. sylvestris (1.6%) and not significant for T. lineola. Isolation by distance analyses revealed a significant correlation for T. sylvestris explaining 20.3% of its differentiation, but no such structure was found for the two other species. Most likely, the high dispersal ability of T. lineola in comparison with T. sylvestris leads to a more or less panmictic structure and hence impedes isolation by distance. On the other hand, the isolation of the populations of T. acteon seems to be so strict that the populations develop independently. Although no general genetic impoverishing was observed for the endangered T. acteon, small populations had significantly lower genetic diversities than big populations, and therefore the high degree of isolation among populations might threaten its local and regional survival.     

Potential metapopulation structure and the effects of habitat quality on population size of the endangered False Ringlet butterfly

The False Ringlet (Coenonympha oedippus) is a European butterfly species, endangered due to the severe loss and fragmentation of its habitat. In Hungary, two remaining populations of the butterfly occur in lowland Purple Moorgrass meadows. We studied a metapopulation occupying twelve habitat patches in Central Hungary. Our aim was to reveal what measures of habitat quality affect population size and density of this metapopulation, estimate dispersal parameters and describe phenology of subpopulations. Local population sizes and dispersal parameters were estimated from an extensive mark–release–recapture dataset, while habitat quality was characterized by groundwater level, cover of grass tussocks, bush cover, height of vegetation and grass litter at each habitat patch. The estimated size of the metapopulation was more than 3,000 individuals. We estimated a low dispersal capacity, especially for females, indicating a very low probability of (re)colonization. Butterfly abundance and density in local populations increased with higher grass litter, lower groundwater level and larger area covered by tussocks. We suppose that these environmental factors affect butterfly abundance by determining the microclimatic conditions for both larvae and adult butterflies. Our results suggest that the long-term preservation of the studied metapopulation needs the maintenance of high quality habitat patches by appropriate mowing regime and water regulation. Management also should facilitate dispersal to strengthen metapopulation structure with creating stepping-stones or gradually increase habitat quality in present matrix.     

Population genetic structure in Myrtus communis L. in a chronically fragmented landscape in the Mediterranean: can gene flow counteract habitat perturbation?

Ancient managed landscapes provide ideal opportunities to assess the consequences of habitat fragmentation on the patterns of genetic diversity and gene flow in long-lived plant species. Using amplified fragment length polymorphism (AFLP) and allozyme markers, we quantified seed-mediated gene flow and population genetic diversity and structure in 14 populations of Myrtus communis (myrtle), a common endozoochorous shrub species of forest patches in lowland agricultural Mediterranean areas. Overall, allozyme diversity for myrtle was low (P₉₅   =   25%; A   =   1.411; H_e = 0.085) compared to other known populations, and a significant portion of populations (57%) had lower levels of allelic diversity and/or heterozygosity than expected at random, as shown by simulated resampling of the whole diversity of the landscape. We found significant correlations between allozyme variability and population size and patch isolation, but no significant inbreeding in any population. Genetic differentiation among populations for both allozyme and AFLP markers was significant (Φ_ST = 0.144 and Φ_ST = 0.142, respectively) but an isolation-by-distance pattern was not detected. Assignment tests on AFLP data indicated a high immigration rate in the populations ( ca. 20–22%), likely through effective seed dispersal across the landscape by birds and mammals. Our results suggest that genetic isolation is not the automatic outcome of habitat destruction since substantial levels of seed-mediated gene flow are currently detectable. However, even moderate rates of gene flow seem insufficient in this long-lived species to counteract the genetic erosion and differentiation imposed by chronic habitat destruction.     

Genetic population structure of the vulnerable bog fritillary butterfly

Populations of the bog fritillary butterfly Proclossiana eunomia (Lepidoptera, Nymphalidae) occur in patchy habitat in central and western Europe. P. eunomia is a vulnerable species in the Belgian Ardennes and the number of occupied sites has significantly decreased in this region since the 1960s. RAPD (random amplified polymorphic DNA) markers were used to study the consequences of habitat loss and fragmentation on the genetic population structure of this species. Gene diversity was lower in populations with smaller population sizes. Genetic subdivision was high (Fst=0.0887) considering the small spatial scale of this study (150 km2). The most geographically isolated population was also the most genetically differentiated one. The genetic population structure and genetic differentiation detected in this study were explained by (1) differences in altitude of the sampled locations and, (2) lower dispersal propensity and dispersal rate in fragmented landscapes versus continuous landscapes. Results from the RAPD analyses were compared with a previous allozyme based study on the same populations. The results of this study suggest that increased fragmentation has lead to a greater genetic differentiation between remaining P. eunomia populations.     

Extreme genetic structure in a social bird species despite high dispersal capacity

Social barriers have been shown to reduce gene flow and contribute to genetic structure among populations in species with high cognitive capacity and complex societies, such as cetaceans, apes and humans. In birds, high dispersal capacity is thought to prevent population divergence unless major geographical or habitat barriers induce isolation patterns by dispersal, colonization or adaptation limitation. We report that Iberian populations of the red‐billed chough, a social, gregarious corvid with high dispersal capacity, show a striking degree of genetic structure composed of at least 15 distinct genetic units. Monitoring of marked individuals over 30 years revealed that long‐distance movements over hundreds of kilometres are common, yet recruitment into breeding populations is infrequent and highly philopatric. Genetic differentiation is weakly related to geographical distance, and habitat types used are overall qualitatively similar among regions and regularly shared by individuals of different populations, so that genetic structure is unlikely to be due solely to isolation by distance or isolation by adaptation. Moreover, most population nuclei showed relatively high levels of genetic diversity, suggesting a limited role for genetic drift in significantly differentiating populations. We propose that social mechanisms may underlie this unprecedented level of genetic structure in birds through a pattern of isolation by social barriers not yet described, which may have driven this remarkable population divergence in the absence of geographical and environmental barriers.     

The genetic consequence of differing ecological demands of a generalist and a specialist butterfly species

Many studies aim at testing the impact of recent fragmentation on the genetic diversity and connectivity of populations, while some species do exist naturally in fragmented landscapes because of their habitat requirements. Therefore, it is important to look at the genetic signatures of species occurring in naturally fragmented landscapes in order to disentangle the effect of fragmentation from the effect of habitat requirements. We selected two Nymphalid butterflies for this purpose. While Melanargia galathea is a common butterfly in flower-rich meadows, Melitaea aurelia is closely connected to calcareous grasslands, thus being historically fragmented due to its ecological demands. For the analysis of the genetic response on these opposed patterns, we analysed 18 allozyme loci for 789 individuals (399 individuals of M. galathea and 390 individuals of M. aurelia) in a western German study region with adjacent areas in Luxemburg and northeastern France. Both species showed similarly low genetic differentiations among local populations (M. galathea: F _ST 3.3%; M. aurelia: F _ST 3.6%), both combined with a moderate level of inbreeding. Isolation-by-distance analysis revealed a significant correlation for both species with similar amounts of explained variances (M. galathea: r ² = 27.8%; M. aurelia: r ² = 28.5%). Most parameters of genetic diversity were higher in M. galathea than in M. aurelia, but the latter species had a considerably higher amount of rare or locally restricted genes; the differing ecological demands are thus reflected in these differences. Both species thus seem to be genetically well suited to their respective ecological requirements. In the light of conservation genetics, we deduce that highly fragmented populations are not necessarily prone to extinction. The extinction risk might be linked to the life history of an organism and its population genetic structure.     

Interactions between habitat quality and connectivity affect immigration but not abundance or population growth of the butterfly, Parnassius smintheus

Habitat geometry has been a primary focus in studies of spatially structured systems. Recent studies have indicated that a more comprehensive approach including habitat quality may be needed, however most previous studies have neglected potential interactions between quality and geometry. We investigated the effects of habitat quality for the butterfly Parnassius smintheus among a series of 17 sub‐populations. Specifically, we examined how habitat connectivity and local nectar flower density affect dispersal, and local population abundance and growth. We first determined which flower species were potentially important by examining nectar flower electivity and then quantified nectar flower density in meadows over a five year period (2003–2007). These data along with meadow connectivity were compared to local population statistics derived from mark–recapture over the same time period. The number of immigrants to a meadow increased as meadow connectivity increased, but showed no direct relationship with nectar flower density; however, there was a significant interaction between meadow connectivity and nectar flower density such that meadows with high connectivity and a high density of nectar flowers received the greatest number of immigrants. The number of emigrants from a meadow increased with increasing habitat quality and connectivity, but showed no interactive effect. The abundance of butterflies increased with meadow connectivity, but showed no relationship with habitat quality or any interactive effect. Separate experiments showed that access to nectar flowers significantly increased female reproductive output, but not lifespan. Despite the effects on immigration and reproductive output, local population growth rates also showed no relationship to nectar flower density. Our results indicate that habitat quality can be important for immigration in spatially structured populations; however, effects of habitat quality may not necessarily translate into higher abundance or population growth. Additionally, habitat quality should not be considered independently from habitat isolation, particularly if it directly affects dispersal. Preserving or augmenting habitat quality will do little to bolster immigration or colonization without adequate connectivity.     

Survival of cold-adapted species in isolated mountains: the population genetics of the Sudeten ringlet,Erebia sudetica sudetica,in the Jeseník Mts., Czech Republic

Relic populations of cold-adapted species, trapped in isolated mountain pockets within the temperate zone, are predicted to suffer considerably due to ongoing climate warming. The butterfly Erebia sudetica sudetica is an example restricted to the Eastern Sudety Mts. Here, the butterfly forms permanent populations on subalpine tall-herb grasslands, but also occupies woodland clearings and hay meadows at lower altitudes. We assume differences among the genetic diversities of the populations due to differences in the temporal continuity of these habitats. Therefore, 17 allozyme loci were analysed for 276 individuals from 13 different localities (six tall-herb stands, two meadows, five forest clearings) in the Jeseník Mts. with a maximum distance of 20 km among them. We obtained a significantly higher genetic diversity for the subalpine populations than for the forest clearing populations. The genetic differentiation among the forest clearing populations was higher than among the subalpine ones. They also showed a significant isolation-by-distance system. These findings support the idea that the lower-elevation populations might have been founded by more than one dispersal event from the subalpine sites, but also secondary colonisations and gene flow in the forest belt. Due to founder effects and possibly further subsequent bottlenecks, these forest clearing populations did not harbour the entire genetic diversity of the taxon. Therefore, conservation actions should focus on the subalpine tall-herb formation.     

Genetic differentiation of the tephritid fly Urophora cardui in Europe as evidence for its biogeographical history

Gaps in the large-scale distribution of the tephritid fly Urophora cardui in Europe have been explained as the results of an ongoing re-immigration from Pleistocene refugia due to a very low dispersal capacity. Following evidence of a much greater dispersal capacity of U. cardui than previously assumed, the pattern of genetic differentiation of 41 populations from 16 European regions was studied using allozyme electrophoresis. In these analyses 18 enzyme systems were scored consistently providing 27 alleles. Allozyme variation indicated high gene flow and low levels of genetic differentiation within and between sampling regions as well as in recently colonized areas. No geographical pattern of heterozygosity or allozyme differentiation could be found matching the previously suggested recent immigration pattern. An observed south-north gradient in allozyme frequencies was interpreted as a geographical cline due to environmental factors. The results corroborate evidence from more recent studies that U. cardui is a highly mobile species which is likely to have repeatedly colonized some suboptimal European regions since the Pleistocene after retreats during 'little ice ages'. Patterns resulting from postglacial immigration processes are likely to have been long wiped out through high exchange rates.     

NONSTATIONARY PATTERNS OF ISOLATION‐BY‐DISTANCE: INFERRING MEASURES OF LOCAL GENETIC DIFFERENTIATION WITH BAYESIAN KRIGING

Patterns of isolation‐by‐distance (IBD) arise when population differentiation increases with increasing geographic distances. Patterns of IBD are usually caused by local spatial dispersal, which explains why differences of allele frequencies between populations accumulate with distance. However, spatial variations of demographic parameters such as migration rate or population density can generate nonstationary patterns of IBD where the rate at which genetic differentiation accumulates varies across space. To characterize nonstationary patterns of IBD, we infer local genetic differentiation based on Bayesian kriging. Local genetic differentiation for a sampled population is defined as the average genetic differentiation between the sampled population and fictive neighboring populations. To avoid defining populations in advance, the method can also be applied at the scale of individuals making it relevant for landscape genetics. Inference of local genetic differentiation relies on a matrix of pairwise similarity or dissimilarity between populations or individuals such as matrices of between pairs of populations. Simulation studies show that maps of local genetic differentiation can reveal barriers to gene flow but also other patterns such as continuous variations of gene flow across habitat. The potential of the method is illustrated with two datasets: single nucleotide polymorphisms from human Swedish populations and dominant markers for alpine plant species.     

Dynamic landscapes shape post‐wildfire recolonisation and genetic structure of the endangered Hermes copper (Lycaena hermes) butterfly

1. The coastal sage scrub vegetation community experiences frequent fires, so the long‐term survival of species depends on the rate of recolonisations exceeding the rate of local extinctions. Recolonisation of these post‐wildfire habitats probably requires long‐distance dispersal events. These movements can also counter detrimental impacts associated with inbreeding. 2. The Hermes copper (Lycaena hermes) is an extremely rare butterfly inhabiting coastal sage scrub adjacent to San Diego, California, USA. Habitat loss due to urbanisation and impacts of recent wildfires has greatly restricted its range, prompting the United States Fish and Wildlife Service to list the Hermes copper as a Candidate Species in 2011. 3. Surveys for Hermes copper butterflies in 2010–2013 documented only two recolonisation events following wildfires in 2003 and 2007. Larger populations were readily detected each year, but detection of smaller populations was inconsistent. 4. Amplified fragment length polymorphism was used to identify potential genetic discontinuities within this species across the landscape. Results indicated that movements across much of the landscape were possible historically. However, individuals from three peripheral populations exhibited a higher degree of differentiation, suggesting more restricted dispersal in these regions. 5. From the results, it can be concluded that historically Hermes copper butterflies were able to move among habitat patches prior to recent changes in the landscape. However, low post‐fire recolonisation rates suggest limited contemporary dispersal, probably due to recent habitat fragmentation. This fragmentation is a relatively new event, as the human population in San Diego County experienced substantial growth in the late 20th Century.     

Population genetics of marine species: the interaction of natural selection and historically differentiated populations

High gene flow, particularly as mediated by larval dispersal, has usually been viewed as sufficient to limit geographic isolation as a major source of population differentiation among marine species. Despite the general observation of relatively little geographic variation among populations of high dispersal marine species many cases of divergence have been observed and natural selection has usually been invoked to explain geographic divergence. Detailed study of several allozyme polymorphisms provided additional evidence that selection may be the predominant force that determines genetic divergence in marine systems. There is, however, growing evidence that marine species with high dispersal are more subdivided than originally thought. The use of multi-locus approaches and the application of molecular techniques have provided new insight into the nature of population divergence in marine species. I argue that (1) many species, which were formerly thought to be unstructured, are in fact subdivided into genetically discrete groups, (2) it is often the case that genetically subdivided populations have distinct evolutionary histories, (3) in many cases, natural selection is the consequence of introgression between these groups, and (4) the combination of molecular assays of both nuclear and mitochondrial DNA and allozyme loci provides the best approach to understanding the evolutionary dynamics of these interacting populations.     

The genetic signature of ecologically different grassland Lepidopterans

The level of genetic diversity found for species is strongly influenced by properties of the species’ ecology, abundance and behaviour (as dispersal). To address this coherence, we selected twenty-two grassland butterfly and burnet moth species, which were previously analysed by allozyme electrophoresis (using 15–25 loci per species) over a study area in western Germany with adjoining areas of Luxembourg and north-eastern France. For this study area, we calculated the species’ specific climatic niche breadths and derived various ecological parameters from literature and own field observations. The obtained parameters of genetic diversity (heterozygosity, number of alleles and percentage of polymorphic loci), genetic differentiation (D _est as well as F _ST and F _IS values as proxis for genetic differentiation among populations and inbreeding within populations), as well as ecological and climatic niche dimensions did not show significant differences among the different Lepidoptera families; therefore taxonomic assignment apparently has a negligible influence on the genetic structure of taxa. Genetic diversity and differentiation showed a significant correlation with the ecological and climatic niche-breadth of species in many cases: generalistic species with rather unspecific ecological characteristics and climatic niche had higher genetic diversities and tend to have lower differentiation and inbreeding, whereas specialist taxa (i.e. with narrow ecological and climatic niches) have lower genetic diversities and higher differentiation and inbreeding. The results might reflect contrasting population structures of specialist species with lower abundances compared with the more common generalists. The more restricted and isolated occurrence of specialists might consequence a reduction in genetic diversity and an increase in genetic differentiation among local populations. In contrast, generalists with unspecific habitat requirements occur in higher abundances and in consequence show a more homogenous genetic structure with higher diversities.     

Extensive local‐scale gene flow and long‐term population stability in the intertidal mollusc Katharina tunicata (Mollusca: Polyplacophora)

The dispersal capabilities of intertidal organisms may represent a key factor to their survival in the face of global warming, as species that cannot adapt to the various effects of climate change will have to migrate to track suitable habitat. Although species with pelagic larval phases might be expected to have a greater capacity for dispersal than those with benthic larvae, interspecies comparisons have shown that this is not always the case. Consequently, population genetic approaches are being increasingly used to gain insights into dispersal through studying patterns of gene flow. In the present study, we used nuclear single‐nucleotide polymorphisms (SNPs) and mitochondrial DNA (mtDNA) sequencing to elucidate fine‐scale patterns of genetic variation between populations of the Black Katy Chiton, Katharina tunicata, separated by 15–150 km in south‐west Vancouver Island. Both the nuclear and mitochondrial data sets revealed no genetic differentiation between the populations studied, and an isolation‐with‐migration analysis indicated extensive local‐scale gene flow, suggesting an absence of barriers to dispersal. Population demographic analysis also revealed long‐term population stability through previous periods of climate change associated with the Pleistocene glaciations. Together, the findings of the present study suggest that this high potential for dispersal may allow K. tunicata to respond to current global warming by tracking suitable habitat, consistent with its long‐term demographic stability through previous changes in the Earth's climate. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 589–597.     

Gene flow among native bush rat,Rattus fuscipes (Rodentia: Muridae), populations in the fragmented subtropical forests of south‐east Queensland

Abstract Many natural populations in areas of continuous habitat exhibit some form of local genetic structure. Anthropogenic habitat fragmentation can also strongly influence the dynamics of gene flow between populations. We used eight microsatellite markers to investigate the population genetic structure of an abundant forest species, the Australian bush rat (Rattus fuscipes), in the subtropical forests of south‐east Queensland. Five sites were sampled, allowing pairwise comparisons within continuous habitat and across clearings. Weak, but significant population differentiation and a significant pattern of isolation by distance was detected over the small scale (<10 km) of this study. Fine‐scale analysis at a single site (<1 km) showed a significant correlation between individual female genetic distance and geographical distance, but no similar pattern among male individuals. There was no evidence of increased population differentiation across clearings relative to comparisons within continuous forest. This was attributed to dispersal within corridors of remnant and revegetated habitat between the forested areas. We concluded that an inherently restricted dispersal ability, female philopatry and natural habitat heterogeneity play an important part in the development of genetic structure among populations of R. fuscipes. It is important to understand the relationship between landscape features and the pattern of gene flow among continuous populations, as this allows us to predict the impact of fragmentation on natural populations.     

Within-patch mobility and flight morphology reflect resource use and dispersal potential in the dryad butterfly Minois dryas

Knowledge of mobility is essential for understanding animal habitat use and dispersal potential, especially in the case of species occurring in fragmented habitats. We compared within-patch movement distances, turning angles, resting times, and flight-related morphological traits in the locally endangered butterfly, the dryad (Minois dryas), between its old populations occupying xerothermic grasslands and newly established ones in wet meadows. We expected that the latter group should be more mobile. Individuals living in both habitat types did not differ in their body mass and size, but those from xerothermic grasslands had wider thoraxes and longer wings, thus lower wing loading index (defined as body mass to wing length ratio). The majority of movements were short and did not exceed 10 m. Movement distances were significantly larger in males. However, there was no direct effect of habitat type on movement distances. Our results suggest that the dryads from xerothermic grasslands have better flight capabilities, whereas those from wet meadows are likely to invest more in reproduction. This implies that mobility is shaped by resource availability rather than by recent evolutionary history. Lower female mobility may have negative implications for the metapopulation persistence because only mated females are able to (re)colonise vacant habitat patches efficiently. Conservation efforts should thus be focused on maintaining large habitat patches that prevent stochastic local extinctions. Furthermore, the recommendation of promoting the exchange of individuals among patches through improving matrix permeability, as well as assisted reintroductions of the species into suitable vacant habitats should also improve its conservation.