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1.
The Duke of Burgundy butterfly has undergone considerable range contractions across Europe and since the 1970s has lost around 84% of its former distribution in the UK. Despite its endangered status, the butterfly is understudied, with few papers directly investigating its habitat requirements. This limited research effort focusses on the larval life stage, with relatively little being known about the adults of the species. In this study, we investigated the habitat usage of both adults and larvae of the Duke of Burgundy. Fieldwork was carried out in association with the Bedfordshire, Cambridgeshire and Northamptonshire (BCN) Wildlife Trust on their Totternhoe Quarry Reserve in Bedfordshire. Using data collected over the course of a decade, we performed the first long term distribution analysis of the species and we identified habitat attributes associated with long-standing abundance hotspots of both adults and larvae on the reserve. We found both life stages to be conserved in their range, remaining in the same small areas of Totternhoe Quarry year on year, with adults often being more restricted in their distribution than larvae. Sheltered locations were important for both life stages, but small differences in habitat preference, such as slope and aspect, were also identified. These results emphasise the need to target management towards both life stages of the Duke of Burgundy, as supporting the larvae alone may not result in suitable environmental conditions for the adults.  相似文献   

2.
Many butterfly species are declining in range and abundance, sometimes to the point of becoming vulnerable to extinction. Several traits increase a species’ vulnerability to population decline through stochastic processes, including high larval specificity and poor dispersal rate. The Duke of Burgundy Hamearis lucina relies on Primula as its sole larval host plant. This monophagus dependency, coupled with susceptibility to environmental stochasticity, low dispersal and poor recolonization potential, means it is vital that sites supporting this rapidly-declining species are managed optimally. Here, we use two calcareous grassland sites in the UK with different grazing systems to identify optimal grazing management for Primula abundance and, for the first time, Primula characteristics linked previously to Duke oviposting preference and success: size, condition, succulence and surrounding sward height. We find that autumn and winter grazing intensity are both positively associated with Primula abundance, but there is a trade-off for winter grazing with negative effects on plant size, condition and succulence. Winter grazing also decreased the sward height below the optimum. Plants were bigger and better at the site managed using continuous (free-roaming) grazing versus the site managed using rotational (paddock-based) grazing. We recommend moderately high grazing intensity during autumn using a free-roaming system where possible to attain abundant Primula, with a reduction in grazing intensity or grazing removal during winter to ensure suitability of individual plants. This management would also benefit other host plants, such as bird’s foot trefoil Lotus corniculatus, which are vital for other declining butterflies that frequently co-occur with Dukes.  相似文献   

3.
In order to improve our understanding of habitat preferences and optimal management of open woodland insects, we analyse patch occupancy and oviposition electivity of the endangered Duke of Burgundy butterfly, Hamearis lucina, in three regions across German habitat types. Some newly available forest clearings created by a severe winter storm in the Schönbuch region were colonised within 2 years, whereas some suitable patches remained unoccupied for several years. We discuss how small population sizes, limited patch connectivity, and habitat quality may contribute to such an intermediate colonisation power. Across study regions, we document differences in oviposition site electivity. On calcareous grassland in the Diemeltal, shaded Primula plants on western slopes were preferentially used, probably to avoid desiccation of the natal food plant. To the contrary, sun-exposed Primula stands were preferred in forest clearings in the Schönbuch and calcareous fens in the Allgäu. In these regions, the risk of desiccation is low, but the overall cool and moist microclimate conditions may hamper larval development in shaded conditions, favouring oviposition at sites with maximum exposition to solar radiation. Optimal management strategies depend on the abiotic and biotic conditions and conservation priorities for the given region and habitat type, and we suggest management regimes that promise to sustain suitable H. lucina habitat at a landscape-level.  相似文献   

4.
The Chalkhill Blue Polyommatus coridon is a widespread butterfly of lowland calcareous grassland in southern Britain and is considered a good indicator of habitat condition. Polyommatus coridon has been identified as a Species of Conservation Concern in the UK Biodiversity Action Plan due to a greater than 25% decline in range size since the 1950s, with losses due to the combined effects of habitat destruction, agricultural intensification and neglect. Analysis of annual butterfly monitoring data (transects) collected at 161 sites from 1981 to 2000 show a three-fold population recovery had occurred. The increases were at established sites, with no re-colonisations or range expansion detected. The 1980s population increase coincided with increases across the species range in stock and rabbit Oryctolagus cuniculus grazing, as well as greater protection and management of sites through protected areas and nature reserves. During the 1990s agri-environment schemes were thought to be the main conservation and policy mechanism driving the favourable conservation status of P. coridon, by facilitating appropriate habitat restoration and management. Weather played a part in the species recovery, with warm, but wet summers associated with increases in abundance. The research provides strong evidence of an important conservation success with the UK Biodiversity Action Plan, with implications for other specialist biodiversity.  相似文献   

5.
Abandonment of farming with the resultant increase in forest cover is one of the major threats to semi-natural grasslands in marginal agricultural areas. In Sweden, the loss of semi-natural grassland is a serious nature conservation problem since it is one of the most species-rich habitats. In this study, the consequences of grassland abandonment and afforestation on butterfly diversity and butterfly dispersal costs are estimated and used to compare three different future land-use scenarios for a marginal agricultural landscape in Sweden. Based on previous butterfly surveys on grasslands in the area, a relationship between land-use type and butterfly diversity was established. By comparing land-use maps of different scenarios, the number of suitable habitat patches and total suitable habitat patch area with low, medium and high butterfly diversity could be estimated. To obtain an indication of possible fragmentation effects, a least-cost analysis was used to compare travel costs of the butterflies between suitable habitat patches for the different scenarios. The results show that different land-use scenarios affect butterfly diversity and travel costs differently. In the extreme case scenario of cessation of full-time farming and a reduction in part-time farming, nearly all valuable butterfly habitats will vanish, since the most species-rich habitats lie in the periphery of the settlement and are expected to be abandoned and afforested first. If, on the other hand, grassland management is less reduced the effect of abandonment on butterflies depends very much on which areas continue to be managed. To preserve the most important grasslands for butterflies an active management strategy for the whole study area would be needed. While it seems relatively easy to identify the areas most important to conserve from a butterfly diversity perspective, it will be more difficult to find an optimal spatial solution that also minimises dispersal costs for butterflies.  相似文献   

6.
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.  相似文献   

7.
Some species cope with, and survive in, urban areas better than others.From a conservation viewpoint it is important to understand why some species arerare or are excluded in the urban landscape, in order that we might take actionto conserve and restore species. Two ecological factors that might explain thedistribution and abundance of butterfly species in the urban landscape aredispersal ability and the availability of suitable habitat. The influence ofthese factors was assessed by examining the distribution and genetic structureof four grassland butterfly species in the West Midlands conurbation, UK. Thefour species differ in their distribution and abundance, mobility and habitatspecificity. No significant fit to the isolation-by-distance model was found forany of the study species at this spatial scale. MeanF ST values revealed a non-significant level ofpopulation structuring for two species, Pieris napi (L.)and Maniola jurtina (L.), but moderate and significantpopulation differentiation for Pyronia tithonus (L.) andCoenonympha pamphilus (L.). Results suggest that thesespecies are limited more by the availability of suitable habitat than by theirability to move among habitat patches. Conservation strategies for thesegrassland species should initially focus on the creation and appropriatemanagement of suitable habitat. More sedentary species that have already beenexcluded from the conurbation may require a more complex strategy for theirsuccessful restoration.  相似文献   

8.
The South African grassland biome is one of the most threatened biomes in South Africa. Approximately 45% of the grassland biome area is transformed, degraded or severely invaded by alien plants and the remaining natural areas are highly fragmented. In this fragmented landscape, the connectivity between habitat patches is very important to maintain viable populations. In this study we aimed to quantify connectivity of the grassland biome in Mpumalanga using graph theory in order to identify conservation priorities and to direct conservation efforts. Graph theory‐based connectivity indices have the ability to combine spatially explicit habitat data with species specific dispersal data and can quantify structural and functional connectivity over large landscapes. We used these indices to quantify the overall connectivity of the study area, to determine the influence of abandoned croplands on overall connectivity, and to identify the habitat patches and vegetation types most in need of maintaining overall connectivity. Natural areas were identified using 2008 land cover data for Mpumalanga. Connectivity within the grassland biome of Mpumalanga was analysed for grassland species with dispersal distances ranging from 50 to 1000 m. The grassland habitat patches were mostly well connected, with 99.6% of the total habitat area connected in a single component at a threshold distance of 1000 m. The inclusion of abandoned croplands resulted in a 33% increase in connectivity at a threshold distance of 500 m. The habitat patches most important for maintaining overall connectivity were the large patches of continuous habitat in the upper and lower centres of the study area and the most important vegetation types were the Wakkerstroom Montane Grassland and the Eastern Temperate Freshwater Wetlands. These results can be used to inform management decisions and reserve design to improve and maintain connectivity in this biome.  相似文献   

9.
Breeding populations of many wading birds have declined globally, primarily caused by habitat degradation and loss. In the UK, population declines have been particularly notable on lowland wet grasslands. In response, some areas of lowland wet grassland have been restored and are under ongoing management to improve the breeding conditions of target species. Here, we assess the efficacy of management measures using a Bayesian framework and controlling for confounding factors. We focus on four wader species, Northern Lapwing Vanellus vanellus, Eurasian Curlew Numenius arquata, Common Snipe Gallinago gallinago and Common Redshank Tringa totanus, that breed in numbers on wet grassland reserve sites in the UK. We collated annual site-specific climate variables, management information (e.g. the creation of wet features and predator control measures) and bird counts between 1994 and 2018. We found the effects of conservation actions varied between intervention types and species. For Lapwing and Redshank, excluding predators by predator-exclusion fencing, especially in combination with fox control, was generally associated with higher breeding counts. For all study species, sites with longer histories of management were associated with higher breeding numbers, with the effect of site age being particularly notable for management on former arable land. Our findings support the effectiveness of targeted conservation actions to achieve high numbers of breeding waders on lowland wet grassland reserves, and also highlight the value of consistent and reliable monitoring data.  相似文献   

10.
Since the 1940s, the distributions of several butterfly species have been expanding in northern Europe, probably in response to climate warming. We focus on the speckled wood butterfly Pararge aegeria in order to determine impacts of habitat availability on expansion rates. We analyse observed expansion rates since 1940 and also use a spatially explicit mechanistic model (MIGRATE) to simulate range expansion in two areas of the UK which differ in their distribution of breeding habitat (woodland). Observed and simulated expansion rates were in very close agreement but were 42%–45% slower in an area that had 24% less woodland. Unlike P. aegeria, the majority of butterfly species are not currently expanding, almost certainly because of lack of suitable habitat. Incorporating the spatial distribution of habitat into investigations of range changes is likely to be important in determining those species that can and cannot expand, and for predicting potential future range changes.  相似文献   

11.
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。  相似文献   

12.
We studied the effects of habitat mosaics on butterfly assemblage on multiple spatial scales: landscape, landscape element, local habitat, and microhabitat, based on the transect counts conducted along a 3.84 km route. The transect route, including 21 local habitats, passed through two distinct areas: 1.65 km of a secondary deciduous Quercus forest and the grove of a shrine in Hiraoka, and 2.19 km of a mosaic of secondary deciduous Quercus forest, grassland, and farmland in Narukawa. The diversity of the landscape elements and species richness were higher in Narukawa than in Hiraoka; the landscape mosaic enhanced the species richness in Narukawa. However, the diversity indices and specialist species (univoltine tree feeder) were decreased in this mosaic landscape. The species richness at local habitats was also increased by the mosaic of microhabitats, such as the herbaceous layer, glade, and mantle in the local habitats, whereas it was decreased by an abundant shrub layer. The ratios of species richness to abundance in the local habitats were lower than expected based on random sampling from the total of Hiraoka and Narukawa. This means that local assemblages were non-random samples from an assemblage on the landscape or regional scale, and were made up by the process of habitat selection of butterfly species in the assemblages on the landscape or regional scale. For conservation of butterfly assemblages, we recommend that woodlands should be kept without fragmentation, but with glades or small grasslands, and with clearance of the shrub layer along the path.  相似文献   

13.
The ecological effects of fire management, especially regarding arthropods are poorly investigated. Burning in winter was assumed to pose a threat to butterfly species hibernating as larvae. To assess the impact of prescribed burning on population viability, we analysed larval-habitat preferences of the highly endangered, xero-thermophilous butterfly Hipparchia fagi in vineyards of the Kaiserstuhl region (southern Germany). Microhabitat preference analyses for mature larvae and egg-laying females revealed a preference of H. fagi for Bromus erectus-dominated communities with sparse vegetation coverage and a distinct tuft growth of the host plant B. erectus on microclimatically benefited slopes. We explain the preference of B. erectus by a preference of vegetation structure. The grass tufts offer a suitable climatically buffered living space for larvae. Egg deposition took place on dry substrate at positions of high solar radiation, thus adapted to hot and dry microclimate. As the larval habitat was sparsely vegetated as well as generally legally protected, fire management was not applicable and therefore not affecting the populations. We think it is conceivable that H. fagi, occurring here at its northern range limit, might expand its larval habitat into denser, combustible B. erectus stands in the course of global warming. A change in habitat preferences would necessitate a re-evaluation of management options.  相似文献   

14.
In contrast to many studies on the habitat quality of road verges for butterflies in relation to management regimes, little is known about whether road verges also function as corridors linking fragmented grassland habitats. We experimentally compared movements of four model species, two small blues and two medium browns, with one habitat specialist and one habitat generalist in each size and phylogenetic category. A total of 425 individual butterflies were caught and translocated to an experimental arena with three 2 × 30 m grassland strips that approximated road verges; one with adult feeding resources, one sheltered from the wind, and one without food and shelter. Movements in grassland strips were compared to movements in continuous grassland habitat. Results indicated that (1) individuals did not use the low-quality strip, (2) only specialists used strips but not in the same way according to their size and phylogenic category, and (3) strip use could not be predicted from habitat selection. This finding supports the idea that corridors of intermediate quality are the most efficient to promote dispersal rates in fragmented landscapes. Road verges cover 250,000 ha in Sweden, which is nearly the total amount of seminatural grasslands. Our results suggest that, to benefit butterfly dispersal among grassland patches, road verges should be managed to create a more favourable microclimate (e.g. sheltered from wind, high temperatures).  相似文献   

15.
Synopsis We quantified bluespine unicornfish, Naso unicornis, movement patterns, home range size and habitat preferences in a small Hawaiian marine reserve. Bluespine unicornfish were site-attached to home ranges situated within the reserve boundaries and their movements were aligned with topographic features. Two different diel movement patterns (‘commuting’ and ‘foraying’) were observed. Commuters made crepuscular migrations of several hundred meters between daytime foraging areas and nighttime refuge holes. Foraying fish did not partake in crepuscular migrations and utilized refuge holes both day and night. Two bluespine unicornfish were also nocturnally active. There was little direct evidence of dispersal from the reserve but differences in bluespine unicornfish abundance and size among reef habitat zones were consistent with ontogenetic habitat shifts. The influence of habitat topography on bluespine unicornfish movements suggests that gross habitat characteristics could be used to predict reef fish movements. This could provide a simple method for setting marine reserve boundaries at sites for which empirical fish movement data are unavailable.  相似文献   

16.
The Influence of Landscape Grain Size on Butterfly Diversity in Grasslands   总被引:6,自引:0,他引:6  
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.  相似文献   

17.
《农业工程》2014,34(1):44-52
In urbanized areas, habitat loss and fragmentation resulting from urban growth and human activities may threaten the biological diversity. It is essential to maintain the connectivity in some isolated and fragmented habitat patches. In 2005, the orchard-based conservation with the legal binding was implemented in Shenzhen to mitigate the ecological threats from forest destruction and to protect the ecological diversity. It is critical to evaluate the efficiency of orchard habitat from the species’ perspective for providing the reference for the habitat management. Based on graph-theoretic methods, we compared the habitats with or without orchards and evaluated the contribution of orchards to the whole network connectivity and its three fractions (intra, flux and connector), and then analyzed the species that could benefit the most from the habitat supplement. We identified the important landscape elements for serving the prioritized conservation. The results showed that orchard-based conservation was an efficient way in maintaining the functional connectivity, which mainly contributed to the intrapatch connectivity and species dispersal flux. The value of orchard incorporation was strongly related with the dispersal ability of threatened species. Our findings indicated that the orchard conservation would be more valuable for species with relatively weak dispersal abilities. We showed the key patches and links that most contribute to uphold functional connectivity in the reserve network. We believe that the assessment based on habitat functional connectivity can effectively serve the practical guidelines of habitat conservation and management in urban areas.  相似文献   

18.
Human alteration of habitat has increased the proportion of forest edge in areas of previously continuous forest. This edge habitat facilitates invasion of exotic species into remaining fragments. The ability of native species to resist invasion varies and may depend on intrinsic variables such as dispersal and reproductive rates as well as external factors such as rate of habitat change and the density of populations of introduced species in edge habitat. We examined the distributional and competitive relationships of two members of the class Chilopoda, Scolopocryptops sexspinosus, a centipede native to the eastern US, and Lithobius forficatus, an exotic centipede introduced from Europe. We found that L. forficatus was most abundant in edge habitat and S. sexspinosus was most abundant in the interior habitat at our field sites. Although L. forficatus was present in habitat interiors at 11 of 12 sites, there was no correlation between fragment size and numbers of L. forficatus in interior habitat. The native centipede was rarely found occupying fragment edges. We used laboratory microcosms to examine potential competitive interactions and to indirectly assess prey preferences of the two species. In microcosms both species consumed similar prey, but the native centipede, S. sexspinosus, acted as an intraguild predator on the introduced centipede. Native centipedes were competitively superior in both intraspecific and interspecific pairings. Our results suggest that intraguild predation may aid native centipedes in resisting invasion of introduced centipedes from edge habitat.  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

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