Boloria Aquilonaris Research Articles

Comparative genetic and demographic responses to climate change in three peatland butterflies in the Jura massif

Climate is a main driver of species distributions, but all species are not equally affected by climate change, and their differential responses to similar climatic constraints might dramatically affect the local species composition. In the context of climate warming, a better knowledge of the ability of dispersal-limited and habitat-specialist species to track climate change at local scale is urgently needed. Comparing the population genetic and demographic impacts of past climate cycles in multiple co-distributed species with similar ecological requirements help predicting the community-scale response to climate warming, but such comparative studies remain rare. Here, we studied the relationship between demographic history and past changes in spatial distribution of three protected peatland butterfly species (Boloria aquilonaris, Coenonympha tullia, Lycaena helle) in the Jura massif (France), using a genomic approach (ddRAD sequencing) and species distribution modeling (SDM). We found a similar and narrow thermal niche among species, and shared demographic histories of post-glacial decline and recent fragmentation of populations. Each species functions as a single metapopulation at the regional scale, with a North-South gradient of decreasing genetic diversity that fits the local dynamics of the ice cover over time. However, we found no correlation between changes in the quantity or the quality of suitable areas and changes in effective population size over time. This suggests that species ranges moved beyond the Jura massif during the less favorable climatic periods, and/or that habitat loss and deterioration are major drivers of the current dramatic decline observed in the three species. Our findings allow better understanding how history events and contemporary dynamics shape local biodiversity, providing valuable knowledge to identify appropriate conservation strategies.

New and interesting records of Lepidoptera in the Ural Mountains (Russia) (Lepidoptera: Papilionoidea, Noctuoidea)

We report new findings of rare and little studied Macrolepidoptera species of the Ural Mountains. The new localities of the rare species are revealed: Euchloe ausonia (Hübner, [1804[), Boloria aquilonaris (Stichel, 1908), Oeneis jutta (Hübner, [1806]), Xestia lorezi (Staudinger, 1891), X. sincera (Herrich-Schäffer, 1851), and Coenophyla subrosea (Stephens, 1829). For the first time, the following species are reported from the Urals: Apamea schildei (Staudinger, 1901), Coranarta cordigera (Thunberg, 1778), Cardepia irrisoria (Erschoff, 1874), Polia vesperugo (Eversmann, 1856), Hadena corrupta (Herz, 1898), and Pseudohermonassa melancholica (Lederer,1853).

The distribution pattern of mire specialist butterflies in raised bogs of the northern lowlands of Central Europe

Raised bogs are extreme and azonal ecosystems with a characteristic hydrological balance, microclimatic conditions and a specific flora and fauna. Recently, these ecosystems have increasingly become the focus of scientific and general attention because of their important ecosystem roles in the face of global warming and providing biodiversity refuges. From a biogeographical and evolutionary context, the peat bogs of the European Lowlands serve as palaeorefugia, acting as cold, edaphic island habitats for arcto-alpine or boreo-montane insect species in temperate biomes. Analysing 105 peat bog sites in the northern lowlands of Central Europe, we compare the diversity and geographic distribution pattern of a subset of six butterfly species, which appear to be tyrphobiontic or tyrphophile mire specialists. We demonstrate a decrease in mean species number in the European Lowlands on a gradient from the east (Northern Belarus, about 4 species) to the west (Northern Germany, about 1 species), and suggest that the decreasing species number may be mainly caused by human impact in the past. The individual distribution pattern shows a nearly complete gap in occurrence of the sensitive bog specialist species Colias palaeno and Boloria eunomia in Northern Germany and an increasing presence of those species in peat bogs of eastern Europe. Boloria aquilonaris shows a different pattern, which, in contrast to C. palaeno, is continuously distributed in all sampled regions and seems to be the more tolerant of tyrphobiontic butterflies in the face of human impact on peat bogs. In the light of other recent findings our results also suggest that Boloria aquilonaris and Plebejus optilete may serve as target species reflecting success in ecological restoration of peat bog ecosystems.

К фауне булавоусых чешуекрылых (Lepidoptera, Papilionoformes) особо охраняемых природных территорий Ленского района (Юго-Западная Якутия)

Five specially protected natural territories have been created to preserve the biological resources of Lensky District in the Republic of Sakha (Yakutia) from the increasing impact of the oil and gas industry. The article presents the results of research on the fauna of butterflies in these territories from 1999 to 2018. Over the time period, 83 species from six families were registered. The research made it possible to evaluate species diversity for each reserve. As a result, common (Aporia crataegi, Colias palaeno, Plebeius argus, P. argyrognomon, Argiades optilete, Cyaniris semiargus, Neptis rivularis, Brenthis ino, Lopinga deidаmia), rare (Ochlodes sylvanus, O. venata, Fixsenia pruni, Neptis sappho, Clossiana titania, Boloria aquilonaris banghaasi, Lasiommata petropolitana, Lopinga achine, Erebia jeniseiensis, E. ligea), and protected (Parnassius eversmanni, Colias hecla viluensis, Phengaris teleius, Neptis sappho, Lasiommata petropolitana) species were revealed.

Sozological analysis of the Butterflies (Lepidoptera, Papilionoidea) of upper bogs in Belarus

The sozological index for boggy species of Papilionoidea group of Lepidoptera inhabiting the territory of Belorussia has been calculated. It is established that 7 species deserve a special attention. The condition of Boloria freija (Becklin, 1791) and B. frigga (Becklin, 1791) populations, having the 1st category of protection, is assessed as critical; these species are classified as rapidly dying out. The condtion of Coenonympha oedippus (Fabricius, 1787) corresponds to the 3rd category of protection, Oeneis jutta (Hübner, 1806) – to the 4th category of protection. Colias palaeno (Linnaeus, 1761) is recommended to be put on the list of preventive protection, and Boloria aquilonaris (Stichel, 1908) to be included into the Red Book on the 3rd category of protection. Coenonympha tullia (Müller, 1764) is considered to be a taxon of preventive protection. The transformation of the environment in the marshes as a result of their desiccation also causes concern, as well as the penetration of some species non-typical for these ecosystems to the upper bogs. It can cause an additional threat to these “conservative” ecosystems due to the possible competition from the invaders, penetration of additional parasites and infectious invasions.

Sex, size and timing: Sampling design for reliable population genetics analyses using microsatellite data

Abstract Population genetics is used in a wide variety of fields such as ecology and biodiversity conservation. How estimated genetic characteristics of natural populations can be influenced by the sampling design has been a long‐standing concern. Multiple simulation and empirical studies illustrated the influence of both sample size and polymorphism of markers. However, our review of studies on butterfly population genetics indicates no consensus on sample size for the estimation of genetic diversity or differentiation. Furthermore, other aspects of sampling design (sex ratio and timing of sampling) were not addressed and their potential impact on genetic parameter estimates rarely explored. Using a large empirical dataset (with spatial and temporal replicates) collected on a butterfly species, Boloria aquilonaris, as well as simulated datasets reflecting (1) three scenarios of migration–genetic drift equilibrium and (2) one scenario of parameter stabilization after 100,000 generations, we quantified the impacts of three aspects of genetic sampling design (namely, sample size, sex ratio and timing of sampling) on the estimation of allele frequencies and its potential downstream impact on the estimation of genetic parameters. With empirical data, we found that sample size and timing of sampling strongly affected the accuracy of allele frequencies and the downstream analyses, while sex ratio did not. Our results were consistent across spatial and temporal replicates. Also, with simulated data, we showed that the genetic sampling design had limited effect in systems where dispersal outweighs genetic drift, while it can have major consequences on our understanding of the genetic diversity and population differentiation in systems dominated by genetic drift (such as most study systems with conservation concerns). We advocate for careful consideration of all aspects of the sampling design in population genetics studies, that is a sufficient number of samples, while ensuring similar sex ratio among sampling locations and collecting with timing appropriate to the question under study. This is particularly important when the study aims at species conservation.

Flight Morphology, Compound Eye Structure and Dispersal in the Bog and the Cranberry Fritillary Butterflies: An Inter- and Intraspecific Comparison.

Understanding dispersal is of prime importance in conservation and population biology. Individual traits related to motion and navigation during dispersal may differ: (1) among species differing in habitat distribution, which in turn, may lead to interspecific differences in the potential for and costs of dispersal, (2) among populations of a species that experiences different levels of habitat fragmentation; (3) among individuals differing in their dispersal strategy and (4) between the sexes due to sexual differences in behaviour and dispersal tendencies. In butterflies, the visual system plays a central role in dispersal, but exactly how the visual system is related to dispersal has received far less attention than flight morphology. We studied two butterfly species to explore the relationships between flight and eye morphology, and dispersal. We predicted interspecific, intraspecific and intersexual differences for both flight and eye morphology relative to i) species-specific habitat distribution, ii) variation in dispersal strategy within each species and iii) behavioural differences between sexes. However, we did not investigate for potential population differences. We found: (1) sexual differences that presumably reflect different demands on both male and female visual and flight systems, (2) a higher wing loading (i.e. a proxy for flight performance), larger eyes and larger facet sizes in the frontal and lateral region of the eye (i.e. better navigation capacities) in the species inhabiting naturally fragmented habitat compared to the species inhabiting rather continuous habitat, and (3) larger facets in the frontal region in dispersers compared to residents within a species. Hence, dispersers may have similar locomotory capacity but potentially better navigation capacity. Dispersal ecology and evolution have attracted much attention, but there are still significant gaps in our understanding of the mechanisms of dispersal. Unfortunately, for many species we lack detailed information on the role of behavioural, morphological and physiological traits for dispersal. Our novel study supports the existence of inter- and intra-specific evolutionary responses in both motion and navigation capacities (i.e. flight and eye morphology) linked to dispersal.

Specialist butterflies benefit most from the ecological restoration of mires

Anthropogenic disturbances cause biotic homogenization through the replacement of specialist species with generalists. Restoration has the potential to counteract these negative effects. Recently, restoration in the peatlands of Northern Europe has started to show positive effects on biodiversity. However, seldom have studies evaluated the response of insects to restoration by comparing populations prior to restoration to those thereafter with a Before-After Control-Impact (BACI) design. The aim of this study was to evaluate whether the restoration actions taken were appropriate to facilitate the successful recolonization of mire butterflies and plants. We found that, generally, drainage was negatively associated with mire specialist butterfly species and butterfly and plant communities, while generalist butterflies were not or were positively associated with drainage. In addition, mire specialist butterflies responded negatively to environmental variables associated with drained mires (number of tall trees) and positively to pristine mire-associated variables (larval food plant cover, number of low trees). Although restoration had a significantly positive effect on only two mire specialist butterflies (Boloria aquilonaris, Colias palaeno), it had a significantly positive effect on overall specialist species abundance. Furthermore, the structure of the butterfly and plant communities in restored sites became more similar to pristine sites a few years after restoration. We conclude that the restoration actions taken (removing tall trees but leaving smaller trees, and raising the water table level) are appropriate in creating suitable habitat conditions for mire butterflies. Finally, appropriate restoration actions in well-prioritized locations can reverse the trend of biotic homogenization.

Conservation genetics of a threatened butterfly: comparison of allozymes, RAPDs and microsatellites.

BackgroundAddressing genetic issues in the management of fragmented wild populations of threatened species is one of the most important challenges in conservation biology. Nowadays, a diverse array of molecular methods exists to assess genetic diversity and differentiation of wild populations such as allozymes, dominant markers and co-dominant markers. However it remains worthwhile i) to compare the genetic estimates obtained using those several markers in order to ii) test their relative utility, reliability and relevance and iii) the impact of these results for the design of species-specific conservation measures.ResultsFollowing the successful isolation of 15 microsatellites loci for the cranberry fritillary butterfly, Boloria aquilonaris, we analyzed the genetic diversity and structure of eight populations located in four different landscapes, at both the regional and the landscape scales. We confront results based on microsatellites to those obtained using allozymes and RAPDs on the same samples. Genetic population analyses using different molecular markers indicate that the B. aquilonaris populations are characterized by a weak genetic variation, likely due to low effective population size and low dispersal at the regional scale. This results in inbreeding in some populations, which may have detrimental consequences on their long term viability. However, gene flow within landscape is limited but not inexistent, with some long range movements resulting in low or no isolation by distance. Spatial structuring was detected among the most isolated populations.ConclusionsThe use of allozymes and RAPD are of very limited value to determine population structuring at small spatial (i.e. landscape) scales, microsatellites giving much higher estimate resolution. The use of RAPD data is also limited for evidencing inbreeding. However, coarse-grain spatial structure (i.e. regional scale), and gene flow estimates based on RAPD and microsatellites data gave congruent results. At a time with increasing development of new molecular methods and markers, dominant markers may still be worthwhile to consider in organisms for which no genomic information is available, and for which limited resources are available.

Plant quality and local adaptation undermine relocation in a bog specialist butterfly

The butterfly Boloria aquilonaris is a specialist of oligotrophic ecosystems. Population viability analysis predicted the species to be stable in Belgium and to collapse in the Netherlands with reduced host plant quality expected to drive species decline in the latter. We tested this hypothesis by rearing B. aquilonaris caterpillars from Belgian and Dutch sites on host plants (the cranberry, Vaccinium oxycoccos). Dutch plant quality was lower than Belgian one conferring lower caterpillar growth rate and survival. Reintroduction and/or supplementation may be necessary to ensure the viability of the species in the Netherlands, but some traits may have been selected solely in Dutch caterpillars to cope with gradual changes in host plant quality. To test this hypothesis, the performance of Belgian and Dutch caterpillars fed with plants from both countries were compared. Dutch caterpillars performed well on both plant qualities, whereas Belgian caterpillars could not switch to lower quality plants. This can be considered as an environmentally induced plastic response of caterpillars and/or a local adaptation to plant quality, which precludes the use of Belgian individuals as a unique solution for strengthening Dutch populations. More generally, these results stress that the relevance of local adaptation in selecting source populations for relocation may be as important as restoring habitat quality.

The fauna and ecology of butterflies (Lepidoptera, Rhopalocera) of the Kanin Peninsula and Kolguev Island

A total of 29 butterfly species in the forest-tundra and 14 species in the hypoarctic tundra were recorded on the Kanin Peninsula. Six species of butterflies were identified on Kolguev Island. The data on the fauna and distribution of species in the forest-tundra of the Kanin Peninsula are generally typical of this natural zone (Chernov and Tatarinov, 2006). The faunas of the northern part of the Kanin Peninsula and the southern part of Kolguev Island comprise fewer species, including those of the Arctic complex. This phenomenon is related to the coastal position of the regions, the cool summer and strong winds. On Kolguev Island, seasonal migrants appear simultaneously with the local species or considerably later. The most abundant species in the forest-tundra of the Kanin Peninsula are Erebia disa, Oeneis norna, Clossiana freija, Pieris napi, and Vacciniina optilete. The dominant species in southern tundra localities are Erebia euryale, E. pandrose, and Boloria aquilonaris, which coincides with the result of the 1903 research (Poppius, 1906). Only the dewy ringlet Erebia pandrose was recorded regularly in the south of Kolguev Island in 2009. In spite of the impoverished fauna of Rhopalocera some butterfly species clearly prevail in abundance and inhabit a wide range of biotopes, which agrees with the concept of compensatory mechanisms (Chernov, 2005). A high abundance of E. pandrose is a specific feature of the northern part of the Kanin Peninsula and Kolguev Island, pointing to the connection of the biota of these territories with the Subarctic regions of Fennoscandia.

Development of novel microsatellite markers for a specialist species of Lepidoptera, Boloria aquilonaris (Nymphalidae), based on 454 sequences

Microsatellites are the most common markers used in population and conservation genetic studies. However, their isola- tion is laborious and expensive. In some taxa, such as Lepidoptera, it is particularly difficult to isolate microsatellite markers due to the high similarity of the flanking regions of different loci and the presence of null alleles. Here we isolated microsatellites of the endangered butterfly Boloria aquilonaris using 454 GS-FLX Titanium pyro-sequences of biotin enriched DNA libraries and tested the success of cross-amplification on the sister-species B. eunomia. Fifteen polymorphic microsatellite loci were isolated in B. aquilonaris using initially 101 stringently designed primer pairs. Unlike in many other studies of microsatellite isolation in Lepidoptera, few null alleles were detected and only at very low frequencies. Additionally, the raw data set can still be used for the isolation of other microsatellite loci. None of the selected polymorphic loci for B. aquilonaris gave clear banding patterns for B. eunomia, although about 15 other loci gave promising banding patterns for the latter species. Low intra- and inter-specific transferability of developed markers in this study also lends support to the hypothesis that the evolution of the genome of Lepidoptera is dissimilar from that of other organisms.

Spatial distribution and mobility of butterflies in a population of the cranberry fritillary Boloria aquilonaris (Lepidoptera, Nymphalidae)

A population of the cranberry fritillary (Boloria aquilonaris) was studied in a forest bog in Southern Karelia. The butterflies in this habitat were distributed unevenly, forming large aggregations in the driest sites overgrown by Comarum palustre. All areas inhabited by the population were interconnected by fluxes of butterflies. The maximum recorded distance covered by a an individual was 1.5 km. The B. aquilonaris residence area was delimited on the basis of an exponential model. Specific features of the spatial organization of B. aquilonaris populations in spatially homogeneous and fragmented environments are discussed.

Species- and sex-specific adjustments of movement behavior to landscape heterogeneity in butterflies

Landscapes are often considered as islands of suitable habitat patches located in a hostile and homogeneous matrix. Variation in matrix quality, however, can be differently perceived by individuals, generating variation in movements related to external conditions (i.e., contrasted boundaries, corridors, or barriers) and/or individual phenotypes (i.e., sex or age). Accordingly,movements may differ both among species and among conspecific individuals of various age and/or sex. Here, we quantified sex-dependent and condition-dependent variations in orientation capacity, exploration behavior, and adjustment of flight speed to landscape heterogeneity in 2 related butterfly species (Boloria aquilonaris and B. eunomia). Using experimental cages, we assessed 1) individual butterfly’s ability to discriminate between habitat and matrices of different types and hence to orientate themselves towards their habitat, 2) individual butterfly’s ability to adapt their flight behavior to their local environment, and 3) their propensity to cross habitat–matrix boundaries. We showed the existence of species-specific orientation capacity, changes in exploration behavior according to local environment, and differences in behavior at habitat boundaries that are consistent between sexes. The adjustment of flight speed was also species-specific and varied in an opposite way between sexes. We explore how these differences might have arisen from adaptive responses to differences in the spatial configuration of habitats and in life-history traits, and we discuss how they can lead to differences in functional connectivity measurements.

Microclimatic buffering and resource‐based habitat in a glacial relict butterfly: significance for conservation under climate change

AbstractIn contrast to several organisms that have already shown range shifts to the north as a response to climate change, southern populations of relict species are trapped in isolated altitudinal habitats. Therefore, there is a growing interest to better understand their habitat use, with particular attention to the thermal aspects and associated significance for their habitat management. We address this issue by a study of larval habitat use relative to vegetation structure and microclimate in a glacial relict butterfly of peat bog ecosystems, using a functional, resource‐based habitat approach. We analysed caterpillar presence and density relative to vegetation composition (reflecting gradients of humidity, temperature, and natural succession of the peat bog) and to the availability and quality of thermal refuges for caterpillars (i.e., structures provided by Sphagnum hummocks). We also tested caterpillar survival rates under different temperature and humidity treatments. We found that (1) Boloria aquilonaris was a specialist butterfly of early successional stages with very humid zones of peat bog, (2) the lack of Sphagnum hummocks reduced larval habitat suitability, and hence the population density, and (3) a reduction of the thermal buffering ability of Sphagnum hummocks was observed in less humid, degraded parts, or late‐successional stages of peat bog. A larval rearing experiment showed a significant impact of temperature on caterpillar survival; survival being higher at lower temperature. Our field and laboratory results support the idea that the thermal environment exploited by caterpillars should be considered as a functional resource and included in a population‐specific habitat definition. Appropriate management of the peat bog habitat of this glacial relict species should not exclusively focus on the larval and adult feeding resources, but also on the quality of thermal refuges provided by Sphagnum hummocks in humid zones of the peat bog, especially in the current critical context of climate warming.

Diurnal butterflies (Lepidoptera, Rhopalocera) of the Solovetskie Islands (Northwestern Russia, the White Sea)

The species composition and diversity of Lepidoptera Rhopalocera were studied on the Solovetskie Islands during five years (2001–2005). Twenty-nine species of five families were recorded. The most abundant species are Leptidea sinapis, Boloria aquilonaris, Heodes virgaureae, Plebejus argus, Arcia eumedon, and Cyaniris semiargus. The fauna of these islands is poorer than local faunas of the continental northern taiga, forest-tundra, and southern tundra of Europe. The species diversity of insular assemblages of diurnal lepidopterans is lower in comparison with analogous continental assemblages. They are characterized by the mixed species composition, when species with different ecological preference occur within the same habitat.

Local population dynamics are important to the conservation of metapopulations in highly fragmented landscapes

Summary 1. Population viability analyses (PVA) are extremely useful tools for the management of endangered species at the landscape scale. Two main families of spatially explicit models are available to perform PVA: (i) presence–absence models, in which local populations are either existing or extinct at each generation, and (ii) structured population models, in which the dynamics of each local population are modelled. In this study we compared the usefulness of both approaches for the prediction of the persistence of a species living in a highly fragmented landscape. 2. The cranberry fritillary Boloria aquilonaris is an arctic–alpine relict species in western Europe. It lives in landscapes where altitude or the proximity of oceans provide the high humidity conditions required for the formation of peat bogs, the only habitat of the butterfly. In such landscapes, the distribution of the butterfly is fragmented, following the natural distribution of peat bogs; this fragmentation is increased by human‐induced peat bog destruction. 3. The study of the dynamics of a highly fragmented metapopulation of the cranberry fritillary in a network of 14 habitat patches totalling 26·23 ha revealed that: (i) the density at the equilibrium was c. 700 butterflies ha−1; (ii) local population dynamics in small populations were negative; and (iii) six estimates of the growth rate Rt showed large variations even in a large population. Both local extinctions and recolonization events are likely to occur, and two sites (one of 7 ha) unoccupied during two generations were recolonized in the third year. 4. We conclude that the future of this metapopulation is not guaranteed, given its large spatial scale and unbalanced, erratic local population dynamics. We hypothesize that global warming could explain the instability of local population dynamics detected here in addition to the decline of this arctic–alpine relict species, which is currently reported in all its refuge localities in the Netherlands. 5. Presence–absence models based on metapopulation structure and habitat characteristics should provide relatively safe predictions, as the population network (14 patches) is just below the minimum amount of suitable habitat (MASH) for the long‐term persistence of a viable metapopulation. However, careful investigation of local population dynamics showed a high instability in the network, which is confirmed by population extinction at a large site. 6. Synthesis and applications. We urge conservation biologists to consider the local population dynamics of endangered species for the management of metapopulations in fragmented landscapes. In the case of the cranberry fritillary, continuing site protection is essential.

The genetic structure of endangered populations in the Cranberry Fritillary, Boloria aquilonaris (Lepidoptera, Nymphalidae): RAPDs vs allozymes.

The genetic population structure of the Cranberry Fritillary Boloria aquilonaris was studied using both RAPDs (random amplified polymorphic DNA) and allozymes. In Belgium, B. aquilonaris has a naturally fragmented distribution that has been accentuated due to human activity during the last century. The genetic population structure of this butterfly was analysed at the regional (several Ardenne uplands) and at the landscape level (several populations within an Ardenne upland). Both population genetic markers confirmed results from a previous CMR study at the landscape scale. At the regional scale however, important incongruences were observed between RAPDs and allozymes. The average gene diversity for the RAPD data was twice that of the allozyme data. The degree of population subdivision was also much greater for RAPDs than for allozymes. The UPGMA clusters produced by each of these markers differed significantly. We believe that, given the higher rate of mutation of RAPDs and the greater number of loci assayed by this method, RAPDs reveal a more accurate and recent population genetic structure than allozymes.

Metapopulation structure and conservation of the cranberry fritillary Boloria aquilonaris (lepidoptera, nymphalidae) in Belgium

The spatial structure and dynamics of local populations of an endangered specialist butterfly, the cranberry fritillary Boloria aquilonaris living on peat bogs was studied in Southern Belgium. Seventeen populations on the Ardenne uplands (Plateau des Tailles, Hautes-Fagnes, Plateau de Recogne, Plateau de St-Hubert) and one population in the forested lowlands of Lorraine were monitored in 1996. The population structure and dynamics were investigated on the “Plateau des Tailles”, the most important area for B. aquilonaris in Belgium with 12 distinct populations. A mark–release–recapture survey was carried out on four sites in 1995 and 1996 within an area of 85 km 2. An unexpectedly high degree of interchange was detected between sites. This connectivity, together with the asynchrony of local dynamics suggest that populations act as a single metapopulation within the whole study area. We observed that adult butterflies were less prone to move out of their natal patch when this patch was small (<1 ha), isolated and sheltered. Therefore, such patches must also be taken into account when planning the conservation of the species.