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1.
Movements and flight morphology of the endangered Large Blue butterflies Phengaris teleius and P. nausithous in southern Poland were studied with mark-release-recapture surveys and GIS analyses. Most individuals moved relatively small distances (<40 metres) within their habitat patches. Distances covered by both species were positively related to season progression and wing length, and negatively related to body mass. P. teleius movement distances slightly exceeded those of P. nausithous. In addition, females moved longer distances than males, although the difference was significant only in P. teleius. Morphological traits appeared to be good indicators of the inter-specific and inter-sexual differences in mobility. While P. teleius individuals were heavier than P. nausithous ones, they had considerably longer wings, which may explain longer movements in the former species. Similarly, females were heavier than males in both species, but they invested more in wing size, which is likely to compensate for the negative impact of body mass on movement distances. Our results indicate that combination of GIS analysis of movement distances recorded with mark-release-recapture methods and morphometric measurements taken in field during non-lethal handling of captured individuals proved useful for studying the mobility potential of the endangered insect species.  相似文献   

2.
1. Understanding the roles of habitat fragmentation and resource availability in shaping animal movement are integral for promoting species persistence and conservation. For insects such as bumble bees, their movement patterns affect the survival and reproductive potential of their colonies, as well as the pollen flow of plant species. However, the understanding of their mobility or the impact of putative barriers in natural environments is limited due to the technical difficulties of studying wild populations. 2. Genetic mark–recapture was used to estimate the foraging distance, resource use, and site connectivity of two bumble bee species in a montane meadow complex composed of open meadows within a matrix of forest. 3. There was no evidence that forests or changes in landcover function as barriers to the fine-scale movement for either species. Substantially greater colony-specific foraging distances were found for Bombus vosnesenskii (maximum: 1867 m) compared to Bombus bifarius (maximum: 362 m). Despite this difference in absolute range, both species were detected across putative forest barriers at frequencies expected by uninhibited movement. Siblings separated by greater distances were more likely to be foraging on different floral species, potentially suggesting a resource-based motivation for movement. 4. These results suggest that bumble bee foraging patterns are influenced by species-specific differences in movement capacity, with little influence of matrix composition between resource patches. They also support the perspective that habitat conservation for bumble bees should prioritise providing abundant and diverse patches of resources within species-specific movement radii with less emphasis on matrix composition.  相似文献   

3.
Plant species differ in their ecological amplitude, with some species occurring in very different habitats under strongly differentiated environmental conditions. We were interested in to what extent the occurrence of Linum catharticum in dry calcareous grasslands (Bromion) and wet litter meadows (Molinion), two habitats on opposing ends concerning, for example, moisture level, is reflected on the genetic and epigenetic level. Using AFLP (amplified fragment length polymorphisms) and MSAP (methylation sensitive amplification polymorphisms) analyses, we studied the genetic and epigenetic variation of L. catharticum from calcareous grasslands and litter meadows. From each habitat, we included five study sites with 16 individuals per sampling location. We observed lower genetic than epigenetic diversity, but considerable differentiation among habitats, which was stronger on the genetic than the epigenetic level. Additionally, we observed a strong correlation of genetic and epigenetic distance, irrespective of geographic distance. The dataset included a large portion of fragments exclusively found in individuals from one or the other habitat. Some epigenetic fragments even occurred in different methylation states depending on the habitat. We conclude that environmental effects act on both the genetic and epigenetic level, producing the clear differentiation among plant individuals from calcareous grasslands and litter meadows. These results may also point into the direction of ecotype formation in this species.  相似文献   

4.
Calcareous grasslands represent local hotspots of biodiversity in large parts of Central and Northern Europe. They support a great number of rare species which are adapted to these xerothermic habitats. Due to massive changes in land use, calcareous grasslands have become a rare habitat type and their conservation has been given a high priority in the habitats directive of the European Union. It is well known that grassland management may affect biodiversity substantially. However, the quality of calcareous grasslands is also influenced by abiotic conditions, such as aspect (i.e. sun exposure), which affects the local mesoclimate. We studied the combined effects of aspect and grassland management on Orthoptera diversity on 16 sites in Central Germany, in an unbalanced crossed design with three factors: aspect, management type and management intensity. For both response variables (diversity and abundance) we obtained a similar pattern. South-facing pastures maintained a greater diversity than north-facing pastures, but both had a greater diversity than extensively used meadows. Intensively used meadows maintained the lowest diversity and abundances. A multivariate analysis revealed that the abundance of rare Orthoptera species correlated with bare ground cover and forb cover, both of which were greatest at south-facing pastures. Our results suggest that grazing is a more suitable management for maintaining a high biodiversity in calcareous grasslands than mowing. Moreover, the mesoclimate (in this studied measured by its surrogate: aspect) is a crucial factor determining species richness and needs to be considered in reserve planning.  相似文献   

5.
Most studies dealing with species distribution patterns on fragmented landscapes focus on the characteristics of habitat patches that influence local occurrence and abundance, but they tend to neglect the question of what drives colonization of previously unoccupied patches. In a study of the dryad butterfly, we combined classical approaches derived from metapopulation theory and landscape ecology to investigate the factors driving colonization from a recent refugium. In three consecutive transect surveys, we recorded the presence and numbers of imagos in 27 patches of xerothermic grassland and 26 patches of wet meadow. Among the predictors affecting the occurrence and abundance of the dryad, we considered environmental variables reflecting (i) habitat patch quality (e.g., goldenrod cover, shrub density, vegetation height); (ii) factors associated with habitat spatial structure (patch size, patch isolation and fragmentation); and (iii) features of patch surroundings (100-m buffers around patches) that potentially pose barriers or provide corridors. Patch colonization by the dryad was strongly limited by the distance from the species refugium in the region; there was a slight positive effect of shrub density in this respect. Butterfly abundance increased in smaller and more fragmented habitat patches; it was negatively impacted by invasive goldenrod cover, and positively influenced by the density of watercourses in patch surroundings. Nectar plant availability was positively related to species abundance in xerothermic grassland, while in wet meadow the effect was the reverse. We conclude that dryad colonization of our study area is very recent, since the most important factor limiting colonization was distance from the refugium, while the habitat quality of target patches had less relevance. In order to preserve the species, conservation managers should focus on enhancing the quality of large patches and should also direct their efforts on smaller and more fragmented ones, including those with relatively low resource availability, because such habitat fragments have an important role to play for specialist species.  相似文献   

6.
Abstract 1. Movement, and particularly the colonisation of new habitat patches, remains one of the least known aspects of the life history and ecology of the vast majority of species. Here, a series of experiments was conducted to rectify this problem with Delphacodes scolochloa Cronin & Wilson, a wing‐dimorphic planthopper of the North American Great Plains. 2. The movement of brachypterous and macropterous planthoppers within and among host‐plant patches was quantified. Also, an experiment was conducted to assess whether planthopper propagule size (i.e. number of colonists) influenced the presence of planthopper adults or eggs over time, planthopper population growth rate (R0), and abundance or impact of an egg parasitoid. 3. Delphacodes scolochloa movement was well described by a simple diffusion model. As expected, brachypters were less dispersive than macropters – mean displacement distances among patches were three times greater for macropters (2.8 m vs. 8.1 m per day). 4. Number of colonists of vacant patches increased with increasing patch size (both wing forms) and decreased with increasing isolation (brachypters only). At the scale of individual potholes (<38 m), brachypters were dispersal limited. 5. Establishment success was strongly influenced by propagule size. An Allee effect constrained the establishment of new populations, but low establishment success was not a result of mate limitations or the presence of natural enemies (i.e. egg parasitoids).6. These movement data reveal important insights regarding the spatial population structure and spread of D. scolochloa.  相似文献   

7.
  1. When species can access all parts of the landscape, species-sorting metacommunity theory predicts that community composition depends on habitat choice and interactions with other species and the environment. These filtering processes can also depend on species' traits.
  2. The authors investigated how traits mediate a species-sorting process in determining butterfly community composition in a naturally patchy landscape in the tropical Western Ghats, India. The authors asked, do traits mediate access to certain habitats and does seasonality affect these patterns? The authors surveyed 56 habitat patches in three habitat types: laterite plateau grasslands, ridge grassland, and moist-deciduous forest, in a 65-km2 landscape.
  3. Non-palatable butterflies showed similar occurrences across seasons and habitats, but palatable butterflies were less commonly encountered in open habitats in the dry season. Polyphagous butterflies occurred infrequently in the dry season in laterite habitats, potentially indicating emigration or diapause patterns are linked to diet breadth.
  4. All species were present in all habitats, implying dispersal does not limit access to different habitat patches, consistent with the species-sorting metacommunity concept. Nevertheless, butterfly occurrence was strongly influenced by the interaction of mobility and habitat type with sedentary species occurring less often in low-resource open laterite patches than mobile species.
  5. Species sorting is typically regarded as occurring directly through environmental filters, but here the authors suggest that the environmental filter acts through movement limitations. Studies integrating landscape heterogeneity and species characteristics will help us better understand metacommunities and species distributions in nature.
  相似文献   

8.
Central European calcareous grasslands are considered biodiversity hotspots, but are severely threatened by the change in land-use and by habitat fragmentation. Coniferous forests are typical adjacent habitats to calcareous grasslands, as abandoned calcareous grasslands are often afforested or develop into coniferous forests by succession. To investigate spillover between calcareous grasslands and coniferous forests, a total of 144 pitfall traps for carabid beetles were placed at three different distances (1, 5, 20 m) from the edge in both habitats at eight locations from April to late August. We found that both habitats had a distinct species assemblage and a decrease in spillover with increasing distance from the habitat edge into the adjacent habitat. Calcareous grasslands were more affected by spillover from the adjacent coniferous forests than vice versa because more forest specialists penetrated into calcareous grasslands than grassland specialists penetrated into coniferous forests. We conclude that spillover into small and isolated habitats can severely change species assemblages, which has to be considered in conservation measures. The protection of large sites with small edge-interior ratios can reduce negative effects on species assemblages in endangered calcareous grasslands.  相似文献   

9.
The main aim of the survey was to describe the diversity and richness of Chilopoda in the selected area of the Bug River valley. The study sites were located in two regions differing in the shape of the valley, the presence of thermophilous habitats and the size of riparian forests. Pitfall traps were used as a sampling method. As a result, 444 specimens belonging to 12 centipede species of two orders – Geophilomorpha (four species) and Lithobiomorpha (eight species) were caught. Lithobius (Monotarsobius) curtipes C.L.Koch, 1847, Pachymerium ferrugineum (C.L.Koch, 1835), Lamyctes (Lamyctes) emarginatus (Newport, 1844) and Lithobius (Monotarsobius) dudichi Loksa, 1947 were the most common and the most numerous species. Of particular note is Lithobius dudichi found in Poland for the first time and previously known based on a single specimen. Two to 10 Chilopoda species were found in each habitat under investigation. The greatest species richness was found in thermophilous thickets (10 species), sandy grasslands (eight), xerothermic grasslands (eight) and mesic meadows (six). The fewest number of species (two) was found in rushes at oxbows and in wet meadows. We found differences in the species composition and the number of Chilopoda between the lower (102 specimens, six species) and the middle (324 specimens, 11 species) section of the river valley. Our results confirm the need to protect xerothermic habitats, unique almost throughout entire Central Europe, which due to their distribution and their small area covered are fairly easily subject to the process of destruction.  相似文献   

10.
Local species richness of butterflies can be expected to benefit from both local habitat properties as well as the availability of suitable habitats and source populations in the surrounding landscape. Whether local species richness is dependent on local or landscape factors can be assessed by examining the relationship between local and landscape species richness. Here we studied how local species richness is related to landscape‐level species richness in landscapes differing in agricultural intensity. The relationship was linear for field boundaries in intensively cultivated landscapes and non‐linear in less‐intensively cultivated landscapes. In landscapes containing semi‐natural grasslands (on average 4% of overall land‐use), the relationship was non‐linear for field boundaries, but linear when considering local species richness of the grasslands themselves. These results show that local factors are more important than landscape factors in determining local species richness in landscapes which contained semi‐natural grasslands. Local species richness was limited by landscape factors in intensively cultivated landscapes. This interpretation was supported by the relationship between local species richness and landscape‐scale average mobility and generalist percentage of butterfly assemblages. We conclude that the management of field boundary habitat quality for butterflies is expected to be most effective in landscapes with semi‐natural grasslands, the species composition of which in turn is dependent on the regional occurrence of grasslands. Based on our results, managing non‐crop habitats for the conservation of habitat specialists and species with poor mobility will be most efficient in regions where patches of semi‐natural grasslands occur.  相似文献   

11.
《Ecography》2003,26(5):641-651
Elements of the landscape, such as patches of preferred habitat, matrix between patches, and corridors linking patches, differ as movement habitat for animals. To understand how landscape structure influences the movement and thus, population dynamics of animals, clear empirical knowledge on patterns of movement is needed. The Siberian flying squirrel inhabits spruce-dominated boreal forests from Finland to eastern Siberia. Numbers of flying squirrels have declined severely in Finland in past decades, probably due to modern forestry. We studied the movement of radio-collared adult flying squirrels in preferred (spruce forest) and in matrix habitat (open areas and other habitats with trees) in Finland 1997–2000, and determined whether the woodland strips connecting patches of preferred habitat could function as ecological corridors for flying squirrels.
Flying squirrels used woodland strips for inter-patch movements, but also used matrix with trees and were able to cross narrow open gaps. Males moved longer total distances and crossed edges more often than females. Males used matrix habitats for movement between spruce patches, and moved faster and more directly in the matrix than in the spruce forest. Females seldom changed spruce patches, but instead used the matrix for foraging. For both sexes probability of leaving the spruce forest patch correlated negatively with the size of the patch, but the type of connection the patch had to other patches did not affect the leaving probability. Due to efficient movement abilities of the flying squirrel and forest-dominated landscape structure of southern Finland, we suggest that conservation acts for maintaining viable populations of flying squirrels should focus on the quality of managed forest and the area of suitable breeding habitat (i.e. on habitat loss), but not necessarily on ecological corridors.  相似文献   

12.
Wetlands are among the most threatened habitat types on our planet. Their decline will probably even intensify under climate change. Many biota are strongly dependent on wetlands, including a large number of invertebrate species. The populations of such hygrophilous species become increasingly disconnected due to the ongoing fragmentation of their habitats. This is particularly true for species with reduced dispersal capacities, such as flightless insects. We studied mobility, population size and microhabitat utilization in a population of an endangered grasshopper species, the Water-meadow Grasshopper, Chorthippus montanus. Our mark-recapture study revealed that the cumulative movement distance of the adults was on average 23.5?m with a maximum of 104?m. The microhabitat analysis showed that both sexes of C. montanus preferred warmer patches with greater radiation than measured at control sites. Niche overlap among sexes was stronger than expected by chance, while niche overlap between insects and controls showed the opposite pattern. Our results suggest that C. montanus is strongly restricted to its habitat and is probably not able to cross larger distances through unsuitable vegetation. Hence, we assume that the populations of this flightless insect species are strongly isolated. However, the effect of the rare macropterous morph of C. montanus on gene flow remains unknown. Wetland restoration is crucial to reconnect the existing wetland patches in Central Europe and thereby reduce the negative effects of habitat fragmentation on wetland species.  相似文献   

13.
Effective conservation of endangered species requires a solid understanding of the demographic causes of population change. Bird populations breeding on agricultural grasslands have declined because their preferred habitat of herb‐rich meadows has been replaced by grassland monocultures. The timing of agricultural activities in these monocultural grasslands is critical, as they often coincide with the nesting phase of breeding birds. Here, we aim to identify the effect of habitat management and targeted nest protection on nest survival of Black‐tailed Godwits Limosa limosa in the Netherlands, a population that has shown a 70% reduction in breeding population size since the 1970s. To protect nests in monocultures from destruction, farmers are paid to either delay mowing or leave a patch of unmown grass around the nest, a patch which in practice varied in size. In herb‐rich meadows, which are typically managed for bird conservation purposes, mowing occurs after hatching. Nest survival declined as the season advanced, more steeply on monocultures than on meadows. Targeted nest protection was only partially successful, as nest predation was considerably higher on mown grassland monocultures with small unmown patches around the nest than in mown monocultures with large unmown patches and in unmown fields. Increased predator densities over the years have been suggested as an important cause of the trend towards lower nest survival, but here we show that nest survival was higher on herb‐rich meadows than on monocultures, and similar to the 1980s. It thus seems that increased predator densities are an increased threat during the egg stage only if habitat quality is low. High‐quality habitat in the form of herb‐rich meadows therefore provides a degree of protection against predators.  相似文献   

14.
Ecosystems are linked by the movement of organisms across habitat boundaries and the arrangement of habitat patches can affect species abundance and composition. In tropical seascapes many coral reef fishes settle in adjacent habitats and undergo ontogenetic habitat shifts to coral reefs as they grow. Few studies have attempted to measure at what distances from nursery habitats these fish migrations (connectivity) cease to exist and how the abundance, biomass and proportion of nursery species change on coral reefs along distance gradients away from nursery areas. The present study examines seascape spatial arrangement, including distances between habitats, and its consequences on connectivity within a tropical seascape in Mozambique using a seascape ecology approach. Fish and habitat surveys were undertaken in 2016/2017 and a thematic habitat map was created in ArcGIS, where cover and distances between habitat patches were calculated. Distance to mangroves and seagrasses were significant predictors for abundance and biomass of most nursery species. The proportions of nursery species were highest in the south of the archipelago, where mangroves were present and decreased with distance to nurseries (mangroves and seagrasses). Some nursery species were absent on reef sites farthest from nursery habitats, at 80 km from mangroves and at 12 km from seagrass habitats. The proportion of nursery/non-nursery snapper and parrotfish species, as well as abundance and biomass of seagrass nursery species abruptly declined at 8 km from seagrass habitats, indicating a threshold distance at which migrations may cease. Additionally, reefs isolated by large stretches of sand and deep water had very low abundances of several nursery species despite being within moderate distances from nursery habitats. This highlights the importance of considering the matrix (sand and deep water) as barriers for fish migration.  相似文献   

15.
In the European Union, the Directive 92/43/EEC defines a number of species and habitats of community interest that are worthy to be preserved because in danger to disappear or because they are representative of the different European bio-geographical regions. In the light of the limited economic resources generally allocated to conservation efforts, there is the necessity to prioritise conservation actions in order to avoid deterioration of protected areas. To this aim, in the present study the most representative habitats of the Italian Alps are compared on the basis of vascular plant biodiversity and a conservation priority index is proposed for each habitat taking into account the potential distribution of 252 threatened vascular plant species. Rocky slopes, screes and alpine grasslands resulted to have the greatest percentage of endemic plant species so reflecting the general distributional pattern of endemic plant species at high altitudes in Eurasian mountains. The relationship between the conservation priority index and the corresponding habitat extent within the Natura 2000 network suggests that peatlands, arid grasslands, wet meadows and freshwater habitats deserve a higher priority in conservation actions. Although vascular plant biodiversity is not necessarily a surrogate of overall biodiversity of Alpine habitats, the results here reported can be used as an initial reference framework for prioritising conservation actions, so as to accomplish the provisions of Article 6 of Habitats Directive.  相似文献   

16.
Some 231 birds were recorded on a sandy plateau in central Sao Paulo, in an area forming a natural "habitat spectrum", from dry or wet grasslands to bushy ones (campo-cerrado) plus gallery scrub, marshes, and low woods. Subtracting 12 species that mostly flew over, and 56 species that seemed to be vagrants or accidental visitors, 163 species were regular (including 14 that center in nearby anthropogenically-modified zones). The 69 in gallery areas are mostly regionally common woodland species, but one southeastern species has disappeared over the years and three northwestern dry-forest species have entered. The 81 grassland species include several rare birds, and hence are important despite exhibiting lower biodiversity than in regional forest areas. Seven rare species disappeared over the years, some due to lack of fires, others because of either recent "greenhouse" dry years or protected vegetation growing to taller campo-cerrado. Several other species are becoming rare. Low vegetation forms a spectrum of temporally unstable habitats that change rapidly; one needs actively managed large areas and corridors even though many open-area birds can fly long distances to varying habitat patches.  相似文献   

17.
In recent years abandonment of traditional management of mountain grasslands has been observed throughout Central Europe. However, the impact of abandonment on vegetation of mountain grasslands is still unclear. In this study it was hypothesized that the cessation of traditional management of mesic mountain meadows causes changes in their species composition and a decrease in the biodiversity. In total, 260 plots were established in the Sudetes (SW Poland) on meadows with regular annual mowing, meadows with irregular mowing management, and abandoned meadows. Relevés (5 × 5 m) were performed, and the habitat properties were determined using Ellenberg indicator values. The study confirmed the hypothesis that the various ways of extensive management have an influence on species richness. The lowest species richness was observed on the irregularly managed meadows, while higher species numbers were found on the abandoned and regular managed meadows. The majority of patches on abandoned meadows exhibited degradation through the expansion of Solidago gigantea, Solidago canadensis, Lupinus polyphyllus, Heracleum sosnovsky, Calamagrostis epigejos, Deschampsia flexuosa, Festuca rubra and Hypericum maculatum. Meadows subjected to different management practices differed significantly in Ellenberg indicator values. The abandoned meadows had the highest values of the light index (L) and nitrogen availability (N), whereas the highest values of soil moisture (F) were noted on the irregularly managed meadows. The degradation of mountain mesic meadows requires regular mowing management, which stops ecological succession and preserves their high biodiversity.  相似文献   

18.
We studied the habitat use and mobility of the Grayling butterfly (Hipparchia semele) and the Blue-Winged Grasshopper (Oedipoda caerulescens), two threatened insects within spatially structured blond and grey dunes in a nature reserve along the Belgian coast. Although both species occur in the same biotope, H. semele were more abundant in open, dynamic sites with a relatively high amount of bare sand, while O. caerulescens preferred sheltered, more stable environments with a lower amount of bare sand. Unlike H. semele, substrate use varied in accordance to body colouration in O. caerulescens, especially on cold days, with light-coloured animals being more abundant on sand and dark-coloured animals more abundant on moss. During a mark-recapture-study, we marked 493 Grayling butterflies and 1289 Blue-Winged Grasshoppers. On average, both sexes of H. semele were equally mobile (about 150 m/day; maximum recorded distance of about 1700 m) while male O. caerulescens were significantly more mobile than females (daily average 47 vs. 5 m; maximum distances observed for O. caerulescens were about 800 m). The importance of habitat heterogeneity (within and among patches) and the consequences of habitat use and mobility of both species for the conservation of typical coastal dune habitats are discussed. The complementary use of species-specific information to site-based management measures is advocated.  相似文献   

19.
We assessed relationships between acoustic frequency, body mass, and habitat in tinamous. This monophyletic group of primitive birds comprises c. 47 ground dwelling species whose habitats range from dense humid forest to open grasslands. The relationship between frequency and body mass was found to be negative, while the songs of open-habitat species exhibited higher frequencies and a wider bandwidth than the closed-habitat ones. Residual variation in song frequency, after controlling for the effect of body mass and phylogeny, tends to differ among habitats. However, a statistical test of this pattern was not possible because of the existence of only five pairs of sister species differing in habitat. In spite of this, positive contrasts of bandwidth were associated with positive contrasts of habitat, confirming that songs of open-habitat species have a wider bandwidth than those of their more closed habitat relatives.  © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77 , 423–430.  相似文献   

20.
The aims of this paper were to find the effects of artificial fertilizer, intensive cultivation and abandonment with afforestation on species composition of traditional meadows at a broad scale, and to describe the ecological variation of different meadow communities. The flora of 21 traditionally managed hay meadows was compared with that of 52 artificially fertilized hay meadows, 28 intensively cultivated grasslands and 29 afforested grasslands by means of classification. Predictors for differences in species composition were tested using multiple regression analyses with associated Monte Carlo permutation tests. Habitat diversity and Ellenberg N were the most important predictors for differences in species composition of traditional meadows. High habitat diversity was associated with maximum occurrences of all kinds of meadow species (high-productive, generalist, low-productive, habitat specialist, regionally rare, vulnerable and orchid species). These meadows are therefore of high conservation value. Traditional meadows contained also some nitrophilous species that dominate artificially fertilized meadows, but in small populations. Artificially fertilized meadows supported the generalist and productive subset of the species from traditional meadows. Thus, artificially fertilized meadows are of low conservation value. As regionally rare and vulnerable species were only recorded at sites with no use of artificial fertilizer, its application should be avoided whenever the aim is to recreate or maintain semi-natural grasslands of high conservation value. Regionally rare and vulnerable meadow species were not recorded in afforested sites, suggesting that afforestation of traditional meadows may have similar negative effects for the traditional meadow flora as the use of artificial fertilizer.  相似文献   

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