Host associations of <Emphasis Type="Italic">Coenonympha hero</Emphasis> (Lepidoptera: Nymphalidae) in northern Europe: microhabitat rather than plant species

Understanding ecological requirements of endangered species is a primary precondition of successful conservation practice. Regrettably, we know surprisingly little about the life history of numerous threatened insects, and about their use of larval host plants in particular. The brown butterflies (Nymphalidae: Satyrinae) have traditionally been considered polyphagous on grasses and indiscriminatory in their oviposition behavior. However, detailed studies on several species have revealed local specialization in host plant use as well as the decisive role of microlimatic conditions as determinants of habitat quality. The present study addresses host plant relationships in the endangered brown butterfly Coenonympha hero (L.) at the northern limit of its European distribution. We combine laboratory-based host preference and performance tests with an analysis of microhabitat use by adult butterflies in the field. Both lines of evidence suggest that C. hero is polyphagous enough not to be associated with one particular host species. Oviposition choices of C. hero are not driven by host plant species but rather by structural characteristics of the substrate. The preferred rigid needle-like structures may serve as cues of ‘transparent’ vegetation which allows the larvae to benefit from sunlight reaching the lower strata of the tuft. Our results suggest that conservation efforts should prioritize microclimatic parameters, rather than the presence of any particular host plant species, as decisive determinants of habitat quality in C. hero.     

Distribution and habitats of <Emphasis Type="Italic">Phengaris</Emphasis> (<Emphasis Type="Italic">Maculinea</Emphasis>) butterflies and population ecology of <Emphasis Type="Italic">Phengaris</Emphasis><Emphasis Type="Italic">teleius</Emphasis> in China

Many species of the butterfly genus Phengaris are regarded as endangered in many parts of their distribution. Several species are also widely distributed across northern China. Due to land use change and overgrazing, their habitats are declining and many patches have been lost. This paper investigates the distribution and habitats of the Chinese Phengaris species (of the subgenus Maculinea). Shrub-grassland near forests seem the most frequent habitat for Phengaris, while flat open grasslands are mostly over-grazed and thus survival for Phengaris butterflies there seems difficult. Throughout Europe, P. teleius is an endangered species, while there is still no information on its status in China. To improve the knowledge on the population ecology of P. teleius, its population structure, adult behaviour and movement were studied through mark–release–recapture methods in the Qinling Mountains of Taibai County. Eight grassland patches which were potentially suitable were found in the area in 2013. In total, 480 individuals (274 females) were marked, resulting in an overall recapture rate of 16 %. The average daily population size was 44 butterflies (±23 SD) during the adult flight period. Sixty-seven percent of the females and 38 % of the males moved less than 50 m, and 17 % of recaptured females and 38 % of males moved more than 200 m. The mean movement distance was 107 ± 177 m for males and 182 ± 122 m for females. The majority of the recaptures (86 %) were made within the patches, only a few individuals (14 %) moved between patches. Due to human disturbance and destruction, all of the eight potentially suitable patches are becoming smaller and increasingly isolated, thus these populations of P. teleius may face an increasing risk of extinction, which may well be a tip of the iceberg of habitat loss and fragmentation of P. teleius in Taibai County and possibly beyond. Hence we hope our initial study of P. teleius could have positive impacts on the conservation of Phengaris butterflies in China.     

Genetic variability and structure of an isolated population of <Emphasis Type="Italic">Ambystoma altamirani</Emphasis>, a mole salamander that lives in the mountains of one of the largest urban areas in the world

Amphibians are globally threatened by habitat loss and fragmentation; species within the order Ambystoma are not the exception, as there are 18 species of mole salamanders in México, of which 16 are endemic and all species are under some national or international status of protection. The mole salamander, Ambystoma altamirani is a microendemic species, which is distributed in central México, within the trans-Mexican volcanic belt, and is one of the most threatened species due to habitat destruction and the introduction of exotic species. Nine microsatellite markers were used to determine the genetic structure, genetic variability, effective population size, presence of bottlenecks and inbreeding coefficient of one population of A. altamirani to generate information which might help to protect and conserve this threatened species. We found two genetic subpopulations with significant level of genetic structure (\(F_{\mathrm{ST}}= 0.005\)) and high levels of genetic variability (\(H_{\mathrm{o}}= 0.883\); \(H_{\mathrm{e}}= 0.621\)); we also found a small population size (\(N_{\mathrm{e}} = 8.8\)), the presence of historical (\(M =\) 0.486) and recent bottlenecks under IAM and TPM models, with a low, but significant coefficient of inbreeding (\(F_{\mathrm{IS}} = -\)0.451). This information will help us to raise conservation strategies of this microendemic mole salamander species.     

Genetic diversity of endangered orchid <Emphasis Type="Italic">Phaius australis</Emphasis> across a fragmented Australian landscape

Historical events such as colonisation, spatial distribution across different habitats, and contemporary processes, such as human-mediated habitat fragmentation can leave lasting imprints on the population genetics of a species. Orchids currently comprise 17% of threatened flora species in Australia (Environment Protection and Biodiversity Conservation Act 1999) due to the combination of fragmentation and illegal harvesting (Benwell in Recovery plan, swamp orchids Phaius australis, Phaius tancarvilliae, NSW National Parks and Wildlife Service, Sydney, 1994; Jones in A complete guide to native orchids of Australia including the island territories, 2nd edn, Reed Natural History, Sydney, 2006; DE in Phaius australis in species profile and threats database, Department of the Environment. http://www.environment.gov.au/sprat, 2015). The federally endangered Swamp Orchid Phaius australis has a disjunct distribution across an almost 2000 km latitudinal range along Australia’s east coast but it was estimated that 95% of the populations have been lost since European settlement (Benwell 1994). Phaius australis is endangered due to illegal collection and habitat loss that has resulted in limited connectivity between populations, in ecosystems that are vulnerable to climate change. Thus the genetic impacts of its history combined with more recent fragmentation may have impacts on its future viability especially in light of changing environmental conditions. Thirty-four populations were sampled from tropical north Queensland to the southern edge of the subtropics in New South Wales. Population genetics analysis was conducted using 13 polymorphic microsatellite markers developed for the species using NextGen sequencing. Spatial genetic patterns indicate post-colonisation divergence from the tropics southwards to its current climate niche limits. Genetic diversity is low across all populations (A?=?1.5, H _e  = 0.171), and there is little evidence of genetic differentiation between regions. Consistent with population genetic theory, the historic loss of populations has resulted in significantly lower genetic diversity in small populations compared to large (P, A, He; p?<?0.05). The viability and persistence of P. australis populations now and in a changing climate are discussed in the context of conservation priorities.     

The effects of introduced vespid wasps (<Emphasis Type="Italic">Vespula germanica</Emphasis> and <Emphasis Type="Italic">V. vulgaris</Emphasis>) on threatened native butterfly (<Emphasis Type="Italic">Oreixenica ptunarra</Emphasis>) populations in Tasmania

Introduced vespid wasps (Vespula germanica and V. vulgaris) are highly efficient predators of native invertebrates. They have the potential to reduce populations of threatened species and change ecosystem dynamics, yet their impact is largely unknown in Australia. The introduction of vespid wasps has coincided with a decline in numbers of threatened Ptunarra brown butterflies (Oreixenica ptunarra) in Tasmania, Australia. The Ptunarra brown butterfly is endemic to Tasmania, where its habitat has been fragmented by clearance for agriculture and forestry. Local extinctions of the species were previously thought to be principally due to its inability to fly the long distances between habitat patches in this disjointed landscape. We investigate the importance of the new threat of vespid wasp predation in the decline of O. ptunarra in the highland grasslands of northwest Tasmania. Numbers of O. ptunarra analysed over a period of 15 years dramatically declined after the arrival of vespid wasps. Wasp control was trialled to determine whether it affected butterfly numbers. Current control methods decreased wasp numbers considerably, resulting in a small increase in butterfly numbers, indicating that wasp predation is keeping O. ptunarra at low densities. Without ongoing conservation measures, it is likely that butterfly numbers will stay low, potentially leading to genetic bottlenecks and more local extinctions. An increase in the intensity of wasp control, in combination with other conservation management methods, is required for the protection and recovery of O. ptunarra.     

All natural habitat edges matter equally for endangered <Emphasis Type="Italic">Maculinea</Emphasis> butterflies

An obvious consequence of habitat fragmentation is an increasing role of habitat edges for species survival. Recently it has been suggested that the endangered butterfly Maculinea nausithous prefers forested edges of its meadow habitats. However, the prevalence of forests in the study area used for this analysis makes it impossible to distinguish whether the effect detected is a genuine preference for forest edges or a preference for any natural patch edges as opposed to patch interiors. We investigated habitat selection by Maculinea nausithous and Maculinea teleius occurring sympatrically at five habitat patches surrounded by mosaic landscape. Butterfly capture positions were marked with GPS and subsequently analysed with GIS software. Both species avoided the interiors of their patches and concentrated in the edge zone, but these preferences were visible only at three larger patches exceeding 1 ha in area. Among different types of edges those bordering densely built-up areas were avoided, whereas all natural edges (adjacent to forests, reeds or grasslands) were similarly used. We hypothesise that preferences towards natural patch edges, regardless of their type, can be explained by the spatial interactions between Maculinea butterflies and Myrmica ants they parasitise. Patch surroundings constitute refuge space for the ants, and hence their densities may be expected to be higher near patch edges. Our findings indicate the importance of patch surroundings for the persistence of Maculinea populations. Regretfully, current legal framework makes it difficult to protect patch surroundings, where neither priority species nor their habitats occur.     

Phenotypic variation of the scarce heath <Emphasis Type="Italic">Coenonympha hero</Emphasis> (L.) (Lepidoptera,Satyridae) from the central part of its range

Variation of the fore and hind wing lengths and the diameters of wing eyespots in two subspecies of Coenonympha hero (L.) from the central part of the species range was analyzed. Clinal variation was revealed, manifested in a gradual increase of the wing size and eyespot diameters from west to east in the Urals. Both in C. h. hero in the Urals and in C. h. perseis in Siberia, the northern peripheral populations had a specific wing pattern with eyespots smaller than in more southern parts of the corresponding ranges. In most cases, such climatic factors as the mean annual air temperature, precipitation, duration of the frost-free period, and humidity were shown to affect significantly the variation of morphological traits of C. hero. Chrono-geographical analysis of variation showed that in some cases the differences between the samples collected in the same locality in different years were comparable to or greater than geographic variation within the subspecies range. Thus, the population as a whole is influenced by climatic factors and weather conditions in a particular part of the range during a particular season; C. hero may therefore be a suitable object for monitoring the impact of environmental changes on insects.     

<Emphasis Type="Italic">Parasitaxus</Emphasis> parasitized: novel infestation of <Emphasis Type="Italic">Parasitaxus usta</Emphasis> (Podocarpaceae)

The world’s sole ‘parasitic’ gymnosperm Parasitaxus usta (Podocarpaceae) is endemic to the island of Grande Terre, New Caledonia. It is a threatened species because of its limited geographic range and progressing habitat fragmentation. Here, we report a novel scale insect outbreak on a Parasitaxus sub-population from Monts Dzumac in the southern part of Grande Terre. The identity of the scale insect was determined through combining morphological and molecular methods. The field collection of scale insects and their secretions from infested Parasitaxus specimens allowed morphological identification of the superfamily Coccoidea. Subsequent genetic sequencing using CO1 markers allowed phylogenetic placement of the wax scale insects to the genus Ceroplastes (Coccoidea, Coccidae), a widespread pest genus. The identified species, C. pseudoceriferus, has not been previously recorded from New Caledonia. As Parasitaxus is already vulnerable to extinction, this new threat to its long-term survival needs to be monitored. Other New Caledonian endemic plant species are potentially at risk of this new species, although it was not observed on Falcatifolium taxoides, the host of Parasitaxus.     

Demographics and spatial ecology in a population of cryptic wood white butterfly <Emphasis Type="Italic">Leptidea juvernica</Emphasis> in Northern Ireland

The cryptic wood white Leptidea juvernica is one of a newly-discovered species complex comprising three morphologically similar species in Europe. In the British Isles, L. juvernica is absent from Great Britain, but is widespread in Ireland, where it has experienced recent declines; it is classed as a priority species in Northern Ireland. Using a mark–recapture approach, this study aims to elucidate the population and spatial ecology of L. juvernica based on a population resident on a small, suburban site and to propose conservation measures. The results demonstrated that populations of L. juvernica, even on small sites, can reach high numbers during the peak flight season. Unusually for European Pieridae, there was only weak evidence of protandry in this population, possibly reflecting weather conditions prior to the flight season. The spatial distribution and abundance of L. juvernica was associated with the distribution of its larval host-plants, as well as maintaining close proximity to south-facing habitat edges for shelter. Males had a closer association to sheltered habitat edges, whilst females were found more commonly on open ground with a shorter sward which was the preferred egg-laying habitat. Long vegetation in sheltered areas was important for roosting during periods of non-activity. These results inform conservation measures which will benefit L. juvernica; appropriate measures focus on habitat management providing a mosaic of open, semi-natural grassland interspersed with tall vegetation, scrub, and trees.     

Spatial genetic structure of an endangered orchid <Emphasis Type="Italic">Cypripedium calceolus</Emphasis> (Orchidaceae) at a regional scale: limited gene flow in a fragmented landscape

Plant species that are capable of propagating clonally are expected to be less vulnerable to habitat fragmentation due to their long life span. Cypripedium calceolus L. is a rare, clonal, long-lived orchid species. It has suffered marked decline because of habitat loss and fragmentation and over-collection, yet an IUCN report on this species does not regard fragmentation as a major threat to the species. We applied 13 nuclear microsatellites and cpDNA sequences to identify the patterns of population structure, genetic diversity and connectivity of six remnant local populations of C. calceolus in highly fragmented Gdańsk Pomerania region (N Poland). Despite severe (80%) loss of localities in the studied area we found that the local populations retain high levels of clonal (R 0.86–1) and genetic diversity (H_e = 0.572). However, their differentiation is relatively high (F_ST = 0.132 for nuclear SSR and F_ST = 0.363 for cpDNA) despite close geographic proximity (0.6–57 km). Bayesian clustering classified populations according to their geographic origin with little admixture. Low genetic connectivity between the remnant populations shows that the current gene flow is too low to serve as a cohesive force in a fragmented habitat, which may impede a quick response to environmental change. The species’ ability to retain ancestral variation may help withstand fragmentation, but in the light of observed extirpation rate it should be rather considered as a factor that only delays local populations’ extinction. This leads to the conclusion that habitat loss and fragmentation should be regarded as a real threat to stability of C. calcelolus populations.     

Habitat loss of a rainforest specialist pollinator fly as an indicator of conservation status of the South American Temperate Rainforests

We estimate habitat loss and fragmentation in a hoverfly, Aneriophora aureorufa, used as a representative forest specialist species. This species is a pollinator specialist of two native trees, forming a triad endemic to the South American Temperate Rainforest (SATR). We combine species distribution models with species-specific requirements to estimate the habitat range of A. aureorufa over two non-overlapping time periods (before human settlement to 2000, and from 2000 to 2014). We analyzed the predicted distribution range of A. aureorufa in Chile, quantifying habitat loss in both periods and fragmentation in the latter. In addition, we evaluated the representativeness of the Chilean protected areas system in relation to the current habitat of the species. We found that the total habitat of A. aureorufa decreased by 68.3% compared to historic pre-settlement levels; in the period 2000–2014 the loss was 4.9%. The northern zone was the most affected by habitat loss and fragmentation, with an estimated total loss of 89.9% from the historic period to 2014, with the loss of 238.2 km² per year between 2000 and 2014. Eighteen percent of the habitat of A. aureorufa occurs within protected areas. We found an overrepresentation in the southern zone (24.79%) and an underrepresentation in the northern zone (3.44%). We propose that forest specialist species of the northern zone of the SATR could be threatened due to the high pressure of habitat loss and the underrepresentation of the Chilean protected areas systems.     

Habitat fragmentation provides a competitive advantage to an invasive tree squirrel, <Emphasis Type="Italic">Sciurus carolinensis</Emphasis>

Changes in the composition of biological communities can be elicited by competitive exclusion, wherein a species is excluded from viable habitat by a superior competitor. Yet less is known about the role of environmental change in facilitating or mitigating exclusion in the context of invasive species. In these situations, decline in a native species can be due to the effects of habitat change, or due to direct effects from invasive species themselves. This is summarized by the “driver-passenger” concept of native species loss. We present a multi-year study of tree squirrels that tested the hypothesis that tree canopy fragmentation, often a result of human development, influenced the replacement of native western gray tree squirrels (Sciurus griseus) by non-native eastern gray tree squirrels (Sciurus carolinensis). We tested this hypothesis along a continuum of invasion across three study sites in central California. We found that within the developed areas of the University of California at Santa Cruz campus and city of Santa Cruz, S. carolinensis excluded S. griseus from viable habitat. The competitive advantage of S. carolinensis may be due to morphological and/or behavioral adaptation to terrestrial life in fragmented hardwood forests. We classify S. carolinensis as a “driver” of the decline of native S. griseus in areas with high tree canopy fragmentation. Future habitat fragmentation in western North America may result in similar invasion dynamics between these species. Our study warrants consideration of existing and predicted interactions between potentially invasive species that co-occur with native species where land use change is proposed.     

Highly diversified population structure of the spider <Emphasis Type="Italic">Lycosa ishikariana</Emphasis> inhabiting sandy beach habitats

Sandy beach ecosystems are decreasing worldwide and organisms living there are becoming threatened. The burrowing wolf spider Lycosa ishikariana is one such example. To establish effective conservation strategies under habitat fragmentation, we examined population genetic structure of L. ishikariana from mitochondrial cytochrome oxidase I gene and 6 microsatellite loci. Mitochondrial sequence data revealed 6 population subgroups with very high fixation indices, indicating that L. ishikariana has a clear phylogeographic structure and that the level of differentiation among regions is considerable. In particular, one subgroup in the western Honshu mainland (clade G) has a highly distinct genetic structure, despite having no clear geographic barriers from its parapatric population. Moreover, the distribution ranges of the other two subgroups (clades D and E) were highly restricted, suggesting their vulnerability to local human impacts and highlighting their high conservation priorities. Microsatellite data revealed 10 subgroups that were compatible with the clades identified from the mitochondrial data. Fixation indices among these groups were very high, indicating a limited gene flow induced by male spiders. Based on these results, we proposed six conservation units of L. ishikariana and effective conservation/restoration strategies in the face of ongoing coastal armoring.     

Predicting the distribution of <Emphasis Type="Italic">Encephalartos latifrons</Emphasis>, a critically endangered cycad in South Africa

This study evaluates how a modelling approach to determine areas of suitable habitat for the Critically Endangered Albany cycad Encephalartos latifrons can assist in systematic conservation planning for this and other rare and threatened cycads. A map distinguishing suitable from unsuitable habitat for E. latifrons was produced and important environmental predictors (climate, geology, topography and vegetation) influencing the suitable habitat were estimated. The maximum entropy (MaxEnt) modelling technique was chosen for this study as it has consistently performed well compared with alternative modelling methods and is also an appropriate model choice when the sample size is small and locality records are relatively few. Predicted habitat suitability showed that some locations chosen for translocation and restoration of E. latifrons specimens are not suitable. This revealed that modelling suitable habitat can guide relocation and regeneration of E. latifrons and perhaps other threatened cycads with restricted distributions and few locality records. The species distribution model constructed for E. latifrons is the first reported habitat model for a Critically Endangered cycad in South Africa. The results may be incorporated into conservation planning and structured decision-making about translocations and restoration programmes involving vulnerable cycads, which are among the most threatened organisms globally.     

Genetic diversity in the locally declining <Emphasis Type="Italic">Laserpitium prutenicum</Emphasis> L. and the more common <Emphasis Type="Italic">Selinum carvifolia</Emphasis> (L.) L.: a “silent goodbye”?

Evaluating the consequences of the decline of threatened species on their population genetic structure is crucial for establishing effective conservation strategies in the strongly fragmented landscapes of Central Europe. Laserpitium prutenicum is a bi- to perennial forb occurring in intermittently wet meadows and light oak forests throughout central to eastern and south-eastern Europe. During the past 70 years, the western limit of its distributional range retracted dramatically, the number of populations decreased and the remaining populations faced a considerable increase of fragmentation. To study the effects of this decline on the genetic diversity of L. prutenicum, we conducted an AFLP study on 20 populations from Germany, Poland and the Czech Republic. For comparison, we collected the same data on Selinum carvifolia, a taxonomically related and both ecologically and morphologically similar species, which is still more common in the study area. Both species showed similarly weak spatial genetic structuring and intermediate genetic diversities. We attribute this result to the loss of habitat being faster than the loss of genetic diversity in smaller and fragmented populations. Depending on the ecological characteristics of a species, even a gradual disappearance is not necessarily accompanied by any detectable effect at the population genetic level (“silent goodbye”). In the case of L. prutenicum, habitat preservation should be given priority over all other conservation measures.     

Adult population ecology and egg laying strategy in the ‘<Emphasis Type="Italic">cruciata</Emphasis>’ ecotype of the endangered butterfly <Emphasis Type="Italic">Maculinea alcon</Emphasis> (Lepidoptera: Lycaenidae)

Population dynamics studies in insects mostly focus on a specific life stage of a species and seldom consider different stages. Here, we studied the population demography of a protected Maculinea alcon ‘cruciata’ population and the factors that could influence the distribution of eggs. The results of the mark-recapture survey showed a relatively short flight period between mid-June and mid-July with a clearly marked early peak period. Unlike in many other butterflies, protandry was not strong. The total population of M. alcon ‘cruciata’ was estimated at 699 individuals. The survival rate, and consequently the average life span, was relatively low. Eggs showed a highly aggregated pattern, and egg numbers were positively related to general shoot size, while the number of flower buds and the features of the surrounding vegetation did not display any effect on egg laying. Based on our findings, the studied population appears viable, but specific management techniques could ensure optimal conditions for egg laying in this protected butterfly.     

Natural re-establishment of a population of a critically endangered primate in a secondary forest: the San Martin titi monkey (<Emphasis Type="Italic">Plecturocebus oenanthe</Emphasis>) at the Pucunucho Private Conservation Area,Peru

The San Martin titi monkey (Plecturocebus oenanthe) is endemic to a small area of northern Peru and is considered Critically Endangered on the IUCN due to massive habitat loss. Between 1994 and 2005 small scale reforestation efforts in the 23.5 ha area of Pucunucho have led to the recuperation of habitat from an area of pasture and crop lands. The first record of P. oenanthe re-establishment in the area is from 2010, although re-establishment probably began earlier. We carried out short population surveys using triangulation to monitor densities of P. oenanthe in Pucunucho in 2011, 2012 and 2016. We estimate the current population of P. oenanthe in this area at 27 individuals, giving population densities of 35 groups/km² and 124 individuals/km². The successful regeneration of habitat and natural re-population of the area by this Critically Endangered species provides evidence of successful reforestation based conservation activities for this and potentially other primate species. Although now protected as a Private Conservation Area, Pucunucho remains threatened.     

Biogeography and phenology of oviposition preference and larval performance of <Emphasis Type="Italic">Pieris virginiensis</Emphasis> butterflies on native and invasive host plants

In invaded environments, formerly reliable cues might no longer be associated with adaptive outcomes and organisms can become trapped by their evolved responses. The invasion of Alliaria petiolata (garlic mustard) into the native habitat of Pieris virginiensis (West Virginia White) is one such example. Female butterflies oviposit on the invasive plant because it is related to their preferred native host plant Cardamine diphylla (toothwort), but larvae are unable to complete development. We have studied the impact of the A. petiolata invasion on P. virginiensis butterflies in the Southeastern USA by comparing oviposition preference and larval survival on both plants in North Carolina (NC) populations without A. petiolata and West Virginia (WV) populations where A. petiolata is present. Larval survival to the 3rd instar was equally low in both populations when raised on A. petiolata. Mean oviposition preference on the two plants also did not differ between populations. However, we found a seasonal effect on preference between early and late season flights within WV populations. Late season females laid 99% of total eggs on A. petiolata while early season females utilized both host plants. Late season females were also less likely to lay eggs than early season females. This change in preference toward A. petiolata could be driven by the early senescence of C. diphylla and suggests a seasonal component to the impact of A. petiolata. Therefore, the already short flight season of P. virginiensis could become further constrained in invaded populations.     

Social structure and landscape genetics of the endemic New Caledonian ant <Emphasis Type="Italic">Leptomyrmex pallens</Emphasis> Emery, 1883 (Hymenoptera: Formicidae: Dolichoderinae), in the context of fire-induced rainforest fragmentation

Habitat fragmentation is a major threat to biodiversity, as it can alter ecological processes at various spatial and trophic scales. At the species level, fragmentation leading to the isolation of populations can trigger reductions in genetic diversity, potentially having detrimental effects on population fitness, adaptability and ultimately population persistence. Leptomyrmex pallens is a widespread rainforest ant endemic to New Caledonia but now confined to habitat patches that have been fragmented by anthropogenic fire regimes over the last 200 years. We investigated the social structure of L. pallens in the Aoupinié region (c.a. 4900 ha), and assessed the impacts of habitat fragmentation on its population genetic structure. Allele frequencies at 13 polymorphic microsatellite loci were compared among 411 worker ants from 21 nests distributed across the region. High within-nest relatedness (r = 0.70 ± 0.02), and a single queen found in 38 % of the nests by pedigree analysis indicate that the species is monogynous to weakly polygynous. Estimates of gene flow and genetic structure across the region were subsequently determined using a combined dataset of single workers per nest and of unrelated foraging workers. These estimates coupled with a comprehensive landscape genetic analysis revealed no evidence of significant population structure or habitat effects, suggesting that the Aoupinié region harbours a single panmictic population. In contrast, analyses of mitochondrial DNA sequence data revealed a high degree of genetic structuring, indicating limited maternal gene flow and suggesting that gene flow among nests is driven primarily by winged males. Overall these findings suggest that fire-induced habitat fragmentation has had little impact on the population dynamics of L. pallens. Additional studies of less mobile species should therefore be conducted to gain further insights into fire related disturbances on the unique biodiversity and function of New Caledonian ecosystems.