Habitat preference and dispersal of the Duke of Burgundy butterfly (Hamearis lucina) on an abandoned chalk quarry in Bedfordshire, UK

The Duke of Burgundy butterfly (Hamearis lucina) has declined severely since the 1970s and is a UK Biodiversity Action Plan Priority species. Its populations are mostly confined to scrubby calcareous grassland, where management for short-turf species can be detrimental to the butterfly. We briefly review the literature on the Duke of Burgundy and investigate their habitat preferences, survival and dispersal at a chalk grassland reserve in Bedfordshire, UK. We found that adults generally preferred more sheltered locations but that their habitat preferences were less restrictive than choice of food-plants. Females chose larger plants with longer leaves in denser patches on which to lay eggs. Adults showed reasonable dispersal ability with turnover recorded between areas isolated by scrub. Our results indicate that the species is able to use isolated areas of favourable habitat at a reserve scale and that conservation could therefore involve cyclic management to provide suitable habitat year-to-year.     

The influence of chalk grasslands on butterfly phenology and ecology

The influence of large‐scale variables such as climate change on phenology has received a great deal of research attention. However, local environmental factors also play a key role in determining the timing of species life cycles. Using the meadow brown butterfly Maniola jurtina as an example, we investigate how a specific habitat type, lowland calcareous grassland, can affect the timing of flight dates. Although protracted flight periods have previously been reported in populations on chalk grassland sites in the south of England, no attempt has yet been made to quantify this at a national level, or to assess links with population genetics and drought tolerance. Using data from 539 sites across the UK, these differences in phenology are quantified, and M. jurtina phenology is found to be strongly associated with both site geology and topography, independent of levels of abundance. Further investigation into aspects of M. jurtina ecology at a subset of sites finds no genetic structuring or drought tolerance associated with these same site conditions.     

松嫩平原不同生境蝴蝶群落多样性及其保护建议

随着气候变化加剧和人类活动影响,生物多样性变化及其保护逐渐受到广泛关注。蝴蝶作为开花植物的传粉媒介和生态环境监测及评价的关键指示者,其多样性变化能够在一定程度上反映生境状况,因此,有必要清晰认识不同生境中的蝴蝶多样性变化。为明确松嫩平原蝴蝶资源和不同生境的群落多样性差异,采用样线法于2016年5月-2018年8月对松嫩平原的割草草地、湿地、农田、放牧利用草地及恢复草地共五种生境类型进行调查研究。结果发现,调查共记录蝴蝶5108头,隶属于6科21属26种,其中牧女珍眼蝶（Coenonympha amaryllis）和红珠灰蝶（Plebejus argyrognomon）为优势种类,分别占蝴蝶个体总数的25.61%和31.66%,且在五种生境类型中均有分布。不同生境类型中,蝴蝶群落的物种丰富度指数和均匀度指数无明显差异,而恢复草地生境的蝴蝶群落Shannon-Wiener多样性指数较高,优势度指数较低。农田生境中的蝴蝶个体数量较少,且群落组成与其他四种生境之间均具有显著差异。五种生境类型中的蝴蝶数量和多样性均呈现一定的月动态和年动态变化趋势。除湿地和农田外,其余三种生境中蝴蝶物种和个体数量从5月到8月均持续升高。四种生境的蝴蝶物种数量、个体数量（除农田外）在2018年均出现明显下降趋势。物种丰富度指数等指标的月动态和年动态在不同生境类型间存在较大差异。这些结果表明,生境类型和人类活动与蝴蝶多样性变化关系密切,表现为单一生境中蝴蝶多样性较低,复杂生境有利于保护蝴蝶多样性。本研究有助于厘清松嫩平原蝴蝶资源的基础数据,并为该地区蝴蝶多样性保护和利用及评估该区域生态环境提供一定理论支撑。     

Natural history museum collections provide information on phenological change in British butterflies since the late-nineteenth century

Museum collections have the potential to provide valuable information on the phenological response of organisms to climate change. This is particularly useful for those species for which few data otherwise exist, but also to extend time series to the period before other observational data are available. To test this potential, we analysed data from 2,630 specimens of four species of British butterflies (Anthocharis cardamines, Hamearis lucina, Polyommatus bellargus and Pyrgus malvae), collected from 1876 to 1999 and stored in the Natural History Museum, London, UK (NHM). In A. cardamines, first-generation P. bellargus and P. malvae, we found that there was a strong significant negative relationship between spring temperature and 10th percentile collection dates, which approximates mean first appearance date, and median collection date, which approximates mean flight date. In all four species, there was a significant negative relationship between the 10th percentile collection date and the length of the collection period, which approximates flight period. In second-generation P. bellargus, these phenological measurements were correlated with summer temperature. We found that the rates of phenological response to temperature, based on NHM data, were similar to, or somewhat greater than, those reported for other organisms based on observational data covering the last 40 years. The lower rate of phenological response, and the significant influence of February rather than March or April temperatures, in recent decades compared with data from earlier in the twentieth century may indicate that early emerging British butterfly species are currently approaching the limits of phenological advancement in response to recent climate warming.     

High-speed railways are not barriers to Pyronia tithonus butterfly movements

Linear infrastructures such as railways and roads can be barriers to the movements of individuals and, hence, may have strong impacts on populations. We tested the barrier effect of a high-speed railway for Pyronia tithonus, a butterfly species showing homing behaviour when displaced. We captured, marked and displaced 152?individuals in two different locations. One-third of the butterflies were released at a capture plot, one-third on the other side of the railway (in a similar habitat) and one-third on the same side but 100?m away from the capture plot. We obtained recapture rates of 40 and 23?% per location. Many (31?%) butterflies crossed the railway, showing homing behaviour. Thus, contrary to wide, busy roads, high-speed railways do not seem to be barriers for these butterflies. We suggest that in an intensive agrarian landscape, railway verges can play a substitution habitat role for grassland butterflies.     

Not only the butterflies: managing ants on road verges to benefit Phengaris (Maculinea) butterflies

Obligate myrmecophilic butterfly species, such as Phengaris (Maculinea) teleius and P. nausithous, have narrow habitat requirements. Living as a caterpillar in the nests of the ant species Myrmica scabrinodis and M. rubra, respectively, they can only survive on sites with both host ants and the host plant Great Burnet Sanguisorba officinalis. After having been reintroduced into a nature reserve in the Netherlands in 1990, both butterfly species expanded their distribution to linear landscape elements such as road verges and ditch edges outside this reserve. As additional habitat of both butterfly species, vegetation management of these landscape elements became important. Our results show that a management beneficial for Phengaris butterflies should aim to increase the nest density of Myrmica species, at the same time reducing the density of nests of the competitor Lasius niger or at least keeping them at a low density. Unfavourable grassland management under which L. niger thrives, includes not mowing or flail-cutting the grass, or depositing dredgings along the side of the ditch. Management favourable for the two Myrmica species differs, demanding some flexibility if both species are to benefit. M. scabrinodis is best supported with early mowing of the road verge vegetation or late mowing in the nature reserve, both of which result in an open vegetation and warm microclimate. In contrast, the nest sites of M. rubra should be left undisturbed during the summer, and mown in late autumn. Mowing of butterfly habitat should be avoided between mid-June and mid-September as this would remove the flowerheads of the Sanguisorba plants, on which the butterflies lay their eggs.     

长江三峡库区蝶类群落的等级多样性指数

在三峡库区蝶类物种多样性调查基础上,从等级多样性角度进行分析,结果表明,蝴蝶属级,科级和等级多样性指数在灌丛生境较高,森林、农田和草地生境多样性较低;非参数检验和方差分析结果表明4种生境在属级和等级多样性上差异显著,灌丛生境和其他生境差异显著。海拔500-1500m高度,蝴蝶的生物多样性相对较高,是库区蝴蝶最重要的生存地带。属级和科级多样性指数的变异系数在森林植被型样本间最大,前者有4个小生境在100％以上,后者有6个小生境超过100%;农田科的变异系数有1个小生境超过100%;草地的属和科变异系数均是1个小生境超过100%;灌丛则全部低于100%。这些数值,反映了三峡库区的形成对蝴蝶的生存及分布的产生了很大的影响,进一步证明库区蝶类生存环境的多样性和破碎化;其中,森林对蝴蝶生存的影响是最复杂的;通过蝴蝶做环境质量评估时,灌丛可作为首选考察对象。     

The Influence of Landscape Grain Size on Butterfly Diversity in Grasslands

The relationship between butterfly diversity and both habitat and landscape variables was studied in two areas of southern Sweden. The habitat quality of the grasslands was similar in the two study areas but the landscape pattern differed in grain size and amount of grassland and forest. Using a transect survey method, a total of 3341 butterflies were observed and 30 taxa identified. We found that both habitat and landscape variables influenced the butterfly diversity of the investigated grasslands. Species composition differed markedly between the two study areas. A study area with a fine-grained landscape pattern, a high cover of semi-natural grassland and many forest edges had twice as many butterfly species but half the number of individuals compared with a coarser-grained study area with larger grasslands widely spread in a matrix of arable fields. The results of our study indicate that both habitat quality and landscape pattern have to be considered when developing conservation strategies for grassland butterflies.     

Does Müllerian Mimicry Work in Nature? Experiments with Butterflies and Birds (Tyrannidae)1

The selective advantage of Müllerian mimicry in nature was investigated by releasing live mimetic and nonmimetic butterflies close to wild, aerial‐hunting tropical kingbirds (Tyrannus melancholicus) and cliff‐flycatchers (Hirundinea ferruginea) in three Amazon habitats (rain forest, a city, and “canga” vegetation). Only mimetic butterflies elicited sight‐rejections by birds, but protection conferred by mimicry was restricted to sites in which both predators and mimics co‐occurred, as in the case of six mimicry rings at a forest site and two at a city site. Most other Müllerian mimics released at city and canga vegetation were heavily attacked and consumed by birds. These results appear to reflect the birds’previous experiences with resident butterfly faunas and illustrate how birds’discriminatory behavior varied among habitats that differed in butterfly species and mimicry ring composition.     

Seasonal fluctuations in butterflies and nectar resources in a semi-natural grassland near Mt. Fuji, central Japan

We investigated seasonal fluctuation patterns in species and individuals of adult butterflies and flowering plants providing nectar in a semi-natural grassland in central Japan. We considered their interrelationships and implications for conservation. The semi-natural grassland included different vegetation structures and management regimes, including: (1) firebreaks where the grass was mowed and removed, (2) plantation areas that were mowed, (3) unpaved roads with mowed banks, (4) abandoned grassland, (5) scattered scrub forest, and (6) the surrounding forest. The sites with management (e.g., firebreaks), plantations and banks of the unpaved road sustained a larger number of butterflies and flowers than sites without management, such as the abandoned grassland, scrub forest and surrounding forest. The number of butterflies increased in the firebreak in June and at all sites in August and September. The firebreak sustained flowers in the spring, and the plantation area and banks of the unpaved road sustained flowers primarily in August and September, which was correlated with the distribution of butterflies. The different treatments such as mowing or mowing with removal of grass induced different numbers of flowers of each species affecting the habitat of adult butterflies through a season. On the other hand, the shrub tree species composing the scrub forest were host plants for the larvae of certain butterfly species. Our results suggest that heterogeneous environments with different human management or different vegetation structure or both could support habitat for various butterfly species, depending on the season and the seral stage.     

Molecular evidence for a recent founder event in the UK populations of the Adonis blue butterfly (<Emphasis Type="Italic">Polyommatus bellargus</Emphasis>)

Contrary to accepted theories of post-glacial colonisation of the UK approximately 10,000 year BP (yBP), historical population data for Polyommatus bellargus suggests the butterfly was either extremely rare or not present before 1775. We examined the phylogeography of the species by sequencing the ‘hypervariable’ mitochondrial control region of UK and French butterflies. Overall, 22 polymorphic nucleotide sites were identified within the control region. French specimens were highly variable, with 17 polymorphic sites, whereas most UK specimens were monomorphic. Average nucleotide diversity was 0.026 (SD 0.016, n = 8) in France, whilst the UK values ranged from 0.00 (n = 6) (for every UK population outside Dorset, n = 43) to 0.01 (SD 0.008, n = 7) (Dorset). The mean number of pairwise differences among the French samples was 7.42, whilst the UK values ranged from 0.00 (all populations except Dorset) to 0.295 (Dorset). One French haplotype differed from the predominant UK version by just a single nucleotide substitution. It seems implausible that the species can have been resident in the UK for 10,000 years without accumulating variation at this mitochondrial region. Thus, the results suggest that either a severe genetic bottleneck or founder event has occurred recently in the UK.     

Effects of managing semi-natural grassland buffers on butterflies

Butterflies are important components of biodiversity in grassland ecosystems and provide ecosystem services such as pollination. Although agricultural intensification has led to a scarcity of native grassland habitats within most agricultural landscapes of North America, fragmented remnants and semi-natural habitats may support diverse communities, including butterflies, as long as vital resources such as host plants are available. The United States Department of Agriculture’s (USDA) Conservation Reserve Program practice CP33 Habitat Buffers for Upland Birds (USDA 2004) provides semi-natural grassland habitat in agricultural landscapes, but a knowledge gap exists about impacts of prescribed disturbance (e.g. burning or disking) on butterflies. We monitored butterfly habitat and butterfly communities on experimentally manipulated CP33 grassland buffers in Clay County, Mississippi from 2007 to 2009. Disturbance guild butterfly species richness did not differ among treatments. However, disturbance guild abundance was positively affected by disking in both the first and second growing seasons following disking, and the magnitude of this response varied between years. Effects of burning on disturbance guild abundance did not differ from the control treatment. There were no treatment differences for grassland guild butterfly abundance and species richness suggesting that periodic disturbance does not unduly impact grassland-associated butterflies in the southeastern US. Our results support current USDA practice standards that require periodic disturbance during the 10-year contract, but restrict the disturbance to 1/3 or 1/4 of grassland buffer area in a given year.     

The effects of habitat fragmentation on niche requirements of the marsh fritillary, Euphydryas aurinia, (Rottemburg, 1775) on calcareous grasslands in southern UK

The marsh fritillary, Euphydryas aurinia, has declined greatly in distribution across its range within Europe, resulting in its designation as a protected species under Annex II of the 1979 Bern Convention and the EC Habitats and Species Directive. The decline has been linked to a marked reduction in the extent of suitable calcareous and wet grassland habitats, habitats which have been lost through conversion of land to agriculture or urban areas, or reduced in quality due to inappropriate management. The UK is now one of the major strongholds for this butterfly in Europe, although much of the remaining habitat is small, isolated and highly fragmented. E. aurinia populations fluctuate greatly due to the combined effects of biotic (e.g. parasitoids) and abiotic (e.g. climate change) factors. We quantified the habitat associations of larval webs of E. aurinia on fragmented versus extensive (unfragmented) calcareous grassland habitat in southern England to test the hypothesis that habitat requirements of E. aurinia are more constrained within fragmented landscapes. Within both fragmented and unfragmented landscapes the quality and quantity of its main host plant in the UK, Succisa pratensis, was positively related to numbers of E. aurinia larval webs found. The sward height was also important at predicting the distribution of larval webs in both landscapes, although the heights were greater within sites in the unfragmented (≈20 cm) compared to fragmented (≈15 cm) landscape. We also found significant effects of elevation and the cover of bare ground on numbers of larval webs. Elevation was strongly correlated with the availability of host plant, whilst bare ground was only significant on sites within the fragmented landscape, showing a negative relationship with number of larval webs. Our results further emphasise the importance of not only maintaining the habitat quality of extant calcareous grassland sites for E. aurinia in the UK, but also increasing the size and connectivity of these sites to increase the chances and rate of (re)colonisation of unoccupied but suitable habitat. In addition, we show that the habitat requirements of E. aurinia on sites in a large unfragmented landscape may be less specific and thus require less extensive management than that required to create optimal conditions necessary at smaller, more isolated sites in fragmented landscapes.     

Habitat complementarity and butterfly traits are essential considerations when mitigating the effects of exotic plantation forestry

Habitat loss threatens insect diversity globally. However, complementary vegetation types in remaining habitat increases opportunities for species survival. We assess the extent to which indigenous forest patches moderate the impact of exotic commercial afforestation on grassland butterflies. Butterflies were sampled in grassland along uncorrelated gradients of landscape-scale indigenous forest and plantation cover, while controlling for variation in local vegetation composition. We separately assessed responses by butterfly groups differing in habitat preference, larval diet, and mobility. There was no effect of landscape- or local-scale variables on species richness, but there was a strong interactive effect of forest and plantation cover on butterfly assemblage structure. The effect varied according to species traits. When forest cover was high, assemblages did not differ at different levels of plantation cover. However, plantation cover significantly influenced assemblage structure when forest cover was low. Grassland with limited forest cover in the protected area supported unique assemblages with high frequency of less mobile, specialized species with herbaceous larval host plants, whereas grassland with low forest cover near plantations had a prevalence of mobile, generalist species. A positive association between forest cover and butterflies with woody larval host plants suggests that indigenous forest patches improved the suitability of fragmented grassland for a subset of butterflies, emphasising the value of natural heterogeneity in transformed areas. However, certain butterfly traits associated with large, open grassland were under-represented in grassland between plantations, underscoring the importance of open areas in the broader landscape to conserve the full diversity of species.

     

Assessing a farmland set-aside conservation program for an endangered butterfly: USDA State Acres for Wildlife Enhancement (SAFE) for the Karner blue butterfly

Private lands provide critical habitat for threatened and endangered species, but only recently have farm-based conservation programs focused on at-risk, invertebrate species. The USDA Conservation Reserve Program State Acres for Wildlife Enhancement (CRP-SAFE) is one of the first federal programs to do so with a Wisconsin-based initiative for the US federally endangered Karner blue butterfly (KBB). This study is the first to evaluate how well the KBB-SAFE provides suitable habitat for the Karner and other butterflies. It also provides a critical foundation for better understanding the potential of new USDA programs that create pollinator habitat including for declining species such as the Monarch butterfly. Here we compare data (2009–2014) on assemblages of grassland communities, blooming floral resource availability, and abundance and richness of butterflies, between KBB-SAFE and native prairie sites. We found that KBB-SAFE and native sites had distinctly different forb species assemblages, with SAFE sites having fewer native blooming species available during the first flight of the KBB yet similar availability during second flight. Butterfly abundance was ultimately greater on native sites compared to SAFE sites, but richness was comparable between sites. We conclude that KBB-SAFE can provide habitat for many grassland species, and serve as surrogate KBB habitat. We provide straightforward management recommendations designed to better meet the needs of the Karner blue and other sensitive butterfly species and we provide further evidence that increased abundance and richness of native forbs and grasses on land formerly used for agriculture can provide habitat for butterflies adapted to early successional habitats.     

Variation in grazing management practices supports diverse butterfly communities across grassland working landscapes

Landscape changes and resource exploitation have driven global biodiversity declines and reduced provision of ecological functions and services. In grassland working landscapes managed for ecological services and livestock production, it is essential to understand the influence of grazing practices on biodiversity to guide conservation. We used grassland butterflies to investigate the effects of four grazing management practices on biodiversity and pollination services from 2015 to 2016. We hypothesized grazing management practices would generate differing floristic resources that would thereby influence grassland butterfly community composition. To address our hypothesis, we sampled floral resources using belt transects and butterfly community and species level dynamics using line-transect distance sampling. We detected 2578 butterflies representing 34 species. Management practice was not a significant predictor of floral (p?=?0.319) or butterfly community composition (p?=?0.604), and sites under the same management showed dissimilarity in ordination space, indicating differences that may not be associated with grazing practices. At the species level, management explained density for six of nine butterfly species, but no individual management practice was optimal for a majority of detected species. Thus, over the timeframe of this study, grazing management practices did not generate differences in floristic community composition to drive community-level responses in grassland butterflies. Rather, management drove differences in individual species’ abundance within the butterfly community, likely contributing to the butterfly diversity observed at a broader scale.     

Mitochondrial DNA and microsatellite markers evidence a different pattern of hybridization in red-legged partridge (Alectoris rufa) populations from NW Italy

Genetic introgression with exotic genomes represents a major conservation concern for the red-legged partridge (Alectoris rufa, Phasianidae). In particular, massive releases of chukar partridges (Alectoris chukar) and/or red-legged × chukar partridge hybrids for hunting purposes have cast serious doubts on the Italian present-day occurrence of wild A. rufa populations not affected by introgressive hybridization. This study investigates the genetic structure of red-legged partridges populations in two ecologically different areas in Northern Italy. Analysis of maternal mitochondrial DNA and biparental microsatellite markers excluded the presence of hybridization in a typical agricultural habitat where hunting and release of reared birds are strictly banned. By contrast, signs of chukar introgression were detected in a perifluvial habitat unusual for the red-legged partridge in Italy. The present study documents the first red-legged partridge population with no genetic evidences of recent chukar introgression presently living in Italy. We recommend that urgent conservation actions are taken to preserve the genetic integrity of this population from the risk of hybridization with farm-reared birds and to support its long-term conservation.     

Local and landscape effects on butterfly density in northern Idaho grasslands and forests

Understanding butterfly response to landscape context can inform conservation management and planning. We tested whether local-scale resources (host and nectar plants, canopy cover) or landscape context, measured at two scales, better explained the densities of four butterfly species. The density of Coenonympha tullia, which has host plants strongly associated with grassland habitats, was positively correlated with the amount of grassland in 0.5- and 1-km radius landscapes and only occurred in forests when they bordered grasslands. For the other species, Celastrina ladon, Cupido amyntula, and Vanessa cardui, local-scale resources better explained butterfly densities, emphasizing the importance of local habitat quality for butterflies. These three species also used host plants that were distributed more heterogeneously within and among habitat types. Our findings demonstrate the importance of host plant spatial distributions when determining the scale at which butterfly density relates to resources, and we recommend that both these distributions and landscape context be evaluated when developing butterfly monitoring programs, managing for species of concern, or modeling potential habitat.     

Chronosequential change in a butterfly community after clear-cutting of deciduous forests in a cool temperate region of central Japan

Transect counts of butterflies were conducted in the northern part of Ibaraki, central Japan, from 1997 to 2001 at 11 census sites, composed of successive stages of deciduous forest development: grassland (one site, early abandoned stage); cutover land (one site, 1–5 years after clear‐cutting); secondary forests (very young (two sites, 6–9 years), middle (two sites, 16–22 years) and old (two sites, 47–51 years)) and old‐growth natural forests (three sites, ≥124 years old). A total of 86 species and 8858 individual butterflies were recorded by 29 sets (406 times) of transect counts. The species richness (number of species), abundance (number of individuals) and diversity indices (Shannon–Wiener H′ and Simpson's 1–λ) of butterflies were high in the early stages (grassland, cutover land and very young secondary forests) of secondary succession. Typical natural forest species increased with the progress of succession, and the old secondary forests and old‐growth natural forests had similar species composition. In contrast, most of the typical natural grassland species were recorded only in the grassland site. In the cutover land site, the number of individuals of grassland species considerably decreased from the first to the second year; furthermore, only one typical natural grassland species was recorded. Thus, the suitable stage for grassland butterfly species lasts for only 1–2 years after clear‐cutting. Old secondary forests (approximately>50 years old) would be able to give refuge to the forest butterfly species, including typical natural forest species. Based on the results, a practical, forestry‐based plan to conserve butterfly diversity was proposed.     

Landscape composition and habitat area affects butterfly species richness in semi-natural grasslands

During the last 50 years, the distribution and abundance of many European butterfly species associated with semi-natural grasslands have declined. This may be the result of deteriorating habitat quality, but habitat loss, resulting in decreasing area and increasing isolation of remaining habitat, is also predicted to result in reduced species richness. To investigate the effects of habitat loss on species richness, we surveyed butterflies in semi-natural grasslands of similar quality and structure, but situated in landscapes of different habitat composition. Using spatially explicit habitat data, we selected one large (6–10 ha) and one small (0.5–2 ha) grassland site (pasture) in each of 24 non-overlapping 28.2 km² landscapes belonging to three categories differing in the proportion of the area that consisted of semi-natural grasslands. After controlling for local habitat quality, species richness was higher in grassland sites situated in landscapes consisting of a high proportion of grasslands. Species richness was also higher in larger grassland sites, and this effect was more pronounced for sedentary than for mobile species. However, the number of species for a given area did not differ between large and small grasslands. There was also a significant relationship between butterfly species richness and habitat quality in the form of vegetation height and abundance of flowers. In contrast, butterfly density was not related to landscape composition or grassland size. When species respond differently to habitat area or landscape composition this leads to effects on community structure, and nestedness analysis showed that depauperate communities were subsets of richer ones. Both grassland area and landscape composition may have contributed to this pattern, implying that small habitat fragments and landscapes with low proportions of habitat are both likely to mainly contain common generalist species. Based on these results, conservation efforts should aim at preserving landscapes with high proportions of the focal habitat.