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1.
The conservation and management of biodiversity requires accurate, repeatable and cost-effective monitoring techniques. In this study, a simple and rapid methodology was employed to measure the quality of different habitats for butterfly species on 10 arable farms in lowland Britain. This habitat monitoring was seven times more rapid than the traditional species-based butterfly monitoring. Data on butterfly abundance were combined with the information gathered on habitat quality at five of the farms using stepwise regression. These models had a consistently high degree of explanatory power for the summary variables of total butterfly abundance and species richness, and the functional groupings of mobile and immobile species. There was good agreement between observed and predicted estimates of species richness and abundance when the models were validated on a further five independent sites. Models to predict the abundance of 11 common butterfly species were also produced. These varied considerably in their predictive power and validity between species. The results clearly demonstrated the beneficial effects of targeted habitat creation for butterflies which is promoted under the Agri-environment Schemes, especially the recently introduced pollen and nectar seed mixtures (WM2) available under the Countryside Stewardship Scheme. The models confirmed the importance of shelter, floristically diverse field margins and the availability of nectar resources from legume species in explaining the abundance of immobile butterfly species in arable landscapes. These sources of nectar and the presence of larval host plants in the crucifer family were important factors in explaining the abundance of mobile species. The results are discussed in terms of the potential of this approach for: (i) assessing habitat quality for butterflies in intensively managed landscapes; (ii) enhancing the value of butterfly monitoring schemes in explaining changes in butterfly abundance at the site and national scale; and (iii) informing habitat management and restoration guidelines for butterfly conservation on arable farmland.  相似文献   

2.
Maculinea nausithous and M. teleius are among the world's rarest butterflies. Both oviposit on the flowerheads of Sanguisorba officinalis, but spend most of their immature lives inside Myrmica spp. ant nests, where their larvae feed on ant brood. Very few colonies of these butterflies survive, and leading conservation bodies have called for urgent research into their habitat requirements: at present, too little is known for successful conservation programmes to be devised.This paper described observations made on three small bogs in France, which each supported colonies of both Maculinea in 1981. The main content is a detailed habitat analysis of each site. Studies were also made of the behaviour of both butterflies, and of the size of the population of each species on every site. From these, it was possible to identify some of the factors that make these sites suitable habitats for M. nausithous and M. teleius. It eas concluded that the abundance, and perhaps the species, of Myrmica ant was the crucial factor on each site.  相似文献   

3.
An increasing number of invasive species are changing ecosystems around the world. Road verges have commonly become the first footholds of non-native species in the new environments. Regularly mown road verges also offer habitats for meadow flora and fauna, which in Europe have suffered from the radical decline of semi-natural biotopes due to the agricultural modernization. We studied impacts of an invasive plant Lupinus polyphyllus on the plant and Lepidoptera species composition along road verges. The plant species composition was studied on 15 sites (with 1 m2 quadrats) and butterflies and diurnal moths along 15 transects (with weekly censuses) in SE Finland, each site and transect representing equally lupine invaded verge and an adjacent non-lupine verge. The species richness and diversity of flora and the cover and species richness of low growing (<20 cm) species, in particular, was lower in lupine verges compared to non-lupine verges. Also, the abundance of butterflies was lower in lupine verges. As the lupine cover approached 100%, fewer butterflies were observed in lupine transects compared to the adjacent non-lupine transects and a higher proportion of individuals were flying. Our results suggest that the changes in plant species assemblages and lower plant species richness in lupine invaded areas had “bottom-up” effects on higher trophic levels. Further studies on the control of lupine are urgently needed, but meanwhile we suggest regular mowing before the lupines have shed their seeds, together with the removal of the cuttings, to be the best management option.  相似文献   

4.
When semi-natural pastures are abandoned, specialized grassland species are lost as a consequence of succession. As a counter-measure, previously abandoned grasslands may be restored by clearing shrubs and trees and re-introducing grazing livestock. In order to examine the effects of this type of habitat restoration, we compared species richness of plants and of specialized plants thought to be dependent on continuous management and species richness and abundance of butterflies and red-listed butterflies in 12 sets of matched continuously managed, abandoned and restored grassland in southern Sweden. We found no differences in species richness or abundance between the three grassland types. There were, however, some negative effects of abandonment. The number of management-dependent plants decreased with increasing cover of trees and shrubs, and in restored sites species richness of all groups decreased with increasing cover of trees and shrubs before restoration. Also the present management significantly affected both butterflies and plants. Species richness of both groups increased with increasing vegetation height and differed between sites depending on the species of grazers, with negative effects of sheep compared to cattle or horses. Our study indicates that for grassland management to be efficient, the restoration actions should mainly be directed towards sites where the post-abandonment succession has not proceeded too far.  相似文献   

5.
This paper introduces and discusses the consistency and effectiveness of an inexpensive modification of Pollard transects for assessing the diversity and abundance of tropical butterfly communities in two national parks in Rio de Janeiro, Brazil. To measure butterfly abundance, students walked simultaneous timed transects at the interface of forest and cleared areas. They either counted the number of individuals observed or tabulated the number of specimens collected with nets. After a short training period, the number of butterflies observed or collected on simultaneous transects was statistically indistinguishable among student groups, and there was a significant positive correlation between observation counts and collected number of individuals. As a measure of species richness, the number of butterfly species sampled on each simultaneous transect was tabulated and did not differ statistically. To measure diversity, alpha of the logseries model was calculated for each collected sample, and statistical fit to a logseries model was determined. Although virtually all daily samples and the year's accumulated sample at one park fit the logseries model, about 35% of the daily samples and the entire year's sample did not fit at the other park. Despite these differences between the two parks, values for alpha from daily samples at both parks varied similarly (from 15 to 50 in almost all cases), and values from the entire year's samples were statistically indistinguishable. The repeatability of results among novices, such as students, suggests that timed transects have great promise for furthering our understanding of butterfly community demographics.  相似文献   

6.
Although edge effects often significantly alter abiotic habitat variables, and the performance and behaviour of plant and animal species, they are rarely taken into account when designing nature reserves or managing the movement of visitors within reserves. In this study, we examined the effects of proximity to a habitat edge, created by a visitor pathway, on reproductive success of the orchids Phaius delavayi and Ponerorchis chusua within the Huanglong National Park, China. Parallel transects were established at different distances from the pathway to test the effects of proximity to the pathway on male and female reproductive success in two consecutive years. For Phaius delavayi, percentage pollinarium removal and percentage fruit set showed significant variation between transects in both years, with plants in transects closer to the pathway having lower reproductive success. P. chusua showed the same trends except for pollinarium removal in one year. These results are consistent with the hypothesis that proximity to the pathway, which is used by a large number of visitors every day throughout the orchids’ flowering seasons, interfered with pollinator activity, depressing male and female reproductive success in both species. The impacts on reproductive success were significant for plants within approximately 10 meters of the pathway. Such edge effects may be common, and may need to be considered when designing nature reserves in which visitor activity is encouraged.  相似文献   

7.
Conservation biology often relies on the protection of (semi)natural habitat remnants. However, the ever increasing human population is taking over natural resources and habitats. Here, contrary to most other studies, we ask how human-associated severe changes in the environment can be used to enrich local biodiversity. We tested if industrial activity (gravel excavation) leads to the creation of habitats that support grassland butterflies and how these areas add to the richness of local species when compared to typical semi-natural habitats (grasslands). We also identified key factors affecting the richness, abundance, diversity and commonness of butterfly species to provide practical recommendations. Species richness, diversity index and the occurrence of rare species were higher in gravel-pit shores than in grasslands. The richness of butterfly species and their abundance were positively affected by the richness of plant species, shrub density and age of the gravel-pit but negatively by the cover of water reservoirs in the surrounding area and the isolation of gravel-pits from grasslands. Butterfly diversity was positively influenced by the richness of plant species and proximity of human settlement but negatively by area of the shore and isolation. Our study is the first one to show the high value of gravel-pits for the conservation of butterflies. We recommend the inclusion of gravel-pits in a system of ecological networks and management of their surroundings to improve the colonization rate of rare species. We suggests that directing interest to the possible positive effects of industrial development on biodiversity may support conservation efforts.  相似文献   

8.
In this study we compared ground beetles (Carabidae) from a range of different forest fragments along an urbanization gradient in Brussels, Belgium. We address the following questions: (i) How does the degree of urbanization in the surrounding habitat affect forest beetles, and does it interact with the effects of patch size and distance to forest edge? (ii) Do these factors have a different effect at the level of individual species, habitat affinity groups or total community? During 2002 we sampled 13 forest plots in 10 forest patches, ranging in size from 5.27 to 4383 ha. The beetles were captured using transects of pitfall traps from the edge to a distance of 100 m into each woodland and identified to species level. Effects of urbanization, forest size and forest edge were evaluated on total species number, abundance and habitat affinity groups and ten abundant, widespread model carabid species. Overall, the effects of urbanization, forest size and edge effects slightly influenced total species richness and abundance but appeared to have a major effect on ground beetle assemblages through species specific responses. More urbanized sites had significantly fewer forest specialists and more generalist species. Large forest fragments were favoured by forest specialist species while generalist species and species frequently associated with forest (forest generalists) dominated the smaller forests. Forest edges mainly harboured generalist species while forest specialist species were more frequent into the forests if the forest patches were large enough, otherwise they disappeared due to the destruction or impoverishment of their habitat. Our results show the importance of differentiating between habitat affinity, especially habitat generalists versus specialists, the latter having a higher value in nature conservation, and merely the quantity of species represented in human-dominated areas.  相似文献   

9.
Factors shaping overall species richness and representation of endangered species of vascular flora and butterflies were determined in 48 nature reserves in Prague, Czech Republic. Total species richness of both groups, and the presence of endangered butterflies, reflect the present status of habitats, while that of endangered plants reflects habitat composition at the time of reserve establishment. Reserve area has a much stronger effect on the species richness of sessile plants than mobile butterflies which, especially endangered species, respond more positively to heterogeneity than to area. Both species richness and endangered species peak in reserves half covered with forest, likely because they harbor species of both woodland and non-woodland habitats, and edge specialists. Solely relying on area and disregarding habitat quality, or a failure to conserve small but high quality sites, may be counterproductive for conserving endangered plant and butterfly species. To conserve diversity of plants and butterflies current management practices, often aimed at maintaining large blocks of pre-selected plant communities, should change to include maintenance of fallows, edges and transient zones.  相似文献   

10.
The increasing spread of invasive alien plants has changed biodiversity throughout the world. To date research in this area has focused on how invasive plant species affect pollinator behaviour, but there is a lack of data on the impact that alien plant species have on wild pollinator populations. Since their introduction in the 19th century, and rapid spread after the 1950s, alien goldenrods (Solidago canadensis, Solidago gigantea) have been among the most successful invasive plant species in Europe. We studied the effects of goldenrods on wild pollinator communities in SE Poland. The abundance, species richness and diversity of wild bees, hoverflies and butterflies were compared between wet meadows invaded by goldenrod (10 transects) and non-invaded controls (10 transects). Furthermore, we compared the plant diversity and average cover between the two groups of sites. Invasion of goldenrods had a very strong negative effect on wild pollinator diversity as well as abundance. Plant diversity and average cover were also negatively affected by goldenrod invasion. Wild pollinators were grouped according to their nesting and food specialization, but none were resistant to the invasion, indicating that introduced goldenrod may affect the entire wild pollinator community. Our study emphasises the urgent need to develop specific protection plans for wild pollinators in habitats threatened by foreign plants and we call for the introduction of programs to stop the invasion of goldenrod not only in Poland, but also on a continental scale.  相似文献   

11.
Roadsides form potential habitats for several grassland species adapted to regular mowing management. We studied the communities of butterflies and day-active moths in 51 sites along the verges of the three road types, i.e., highways, urban roads and rural roads. Despite different traffic densities and widths of the road and verge, the groups were rather similar with regard to soil properties, vegetation structure and mowing intensity. The species richness and total abundance of butterflies (53 species, 5964 individuals) and diurnal moths (46 species, 4626 individuals) were also rather similar in each road type, although a preference for wider verges was observed. Butterfly diversity increased (but not significantly) from the verges of narrow rural roads to wider highways. The highest numbers of meadow species were recorded along highways and the total abundance, especially of diurnal moths, decreased in accordance with the road size. High nectar abundance was the most important factor increasing the numbers of meadow butterflies along road verges, while meadow moths were mostly favoured by shelter provided by tall vegetation. Verges surrounded by cultivated fields were generally related to low numbers of both Lepidoptera groups, whereas adjacent forests increased the total number of all species and favoured several butterflies inhabiting forest edges. The adjacent environment inflicted compositional differences on the Lepidoptera fauna of the three road types. The results indicate that road verges should be considered an important reserve for species dependent on semi-natural grasslands in Finland. A growing interest in accommodating current roadside management for conserving biodiversity is likely to benefit Lepidoptera communities in the verge habitats.  相似文献   

12.
生境特异性(habitat-specific)在维持生物多样性上发挥着重要作用。本研究旨在了解在区域景观中,不同类型生境对不同类群昆虫多样性的贡献及群落结构差异,从大尺度上探讨昆虫多样性分布格局和维持机制。于2019年8—9月,在西双版纳地区利用样线调查法,调查了保护区、次生林、人工林和农田4种生境中蝴蝶、蝽和甲虫的物种数、特有物种数,分析了昆虫群落的生境特异性指数、群落结构相似性及物种丰富度与生态因子的关系。共采集昆虫2588头,其中蝴蝶94种(744头),蝽197种(1094头),甲虫129种(750头),保护区的昆虫物种数和特有物种数均高于其余类型生境。保护区昆虫群落的生境特异性指数实测值高于期望值,而其余类型生境昆虫群落的生境特异性指数实测值均低于期望值;不同类型生境间,3个类群的昆虫群落汇总的生境特异性指数不存在显著差异(F_(3,57)=2.054),甲虫生境特异性指数差异显著(F_(3,55)=3.478),蝴蝶(F_(3,38)=1.504)和蝽类(F_(3,53)=1.153)生境特异性指数差异不显著。群落结构相似性分析显示,保护区和农田的3个类群昆虫群落汇总的群落结构差异显著;次生林和人工林的蝴蝶群落结构差异显著,保护区和次生林的蝽类群落结构差异显著,甲虫昆虫群落结构差异不显著。本研究还发现,只有生境类型对昆虫群落的物种丰富度产生的影响极显著(P0.01),而其他生态因子的影响不显著。在大尺度区域景观中,保护区对昆虫群落的多样性影响最大,生境类型与昆虫群落的物种丰富度密切相关,保护较好的天然林是维持区域昆虫群落分布格局和多样性的重要机制。  相似文献   

13.
Roughly 90% of butterfly species live in the tropics. Despite this, we know very little about tropical butterfly ecology particularly when compared to temperate butterfly systems. The relative scarcity of data on tropical butterfly populations hampers our ability to effectively conserve them. In this review we summarize recurring themes from ecological research on tropical butterflies to serve as a framework for understanding their conservation. Key themes include: (1) the tropics represent the evolutionary origins of butterfly diversity, (2) while some tropical butterflies exhibit relatively stable population dynamics, longer-lived adult stages, and more continuous age-specific reproduction compared to temperate zone species, the generality of these patterns is debatable, and (3) complex species interactions (e.g. mimicry, parasitism and predation) can have significantly greater influences on ecological and evolutionary processes in tropical butterflies than in temperate ones. This state of ecological knowledge, combined with scarce resources, has traditionally constrained tropical butterfly conservation efforts to habitat level approaches, unlike the species- and population-specific approaches familiar in North America and Europe. Consequently, much conservation research on butterflies in the tropics has focused on the relationship between habitat quality (e.g. forest fragmentation) and butterfly diversity, though predictive patterns even in this regard remain elusive. We argue that with the increasing threats of habitat destruction, fragmentation and climate change, it is necessary to move beyond this diversity and habitat relationship if we are to improve predictive capabilities when evaluating anthropogenic impacts on tropical butterfly communities. Tropical butterflies are more than just useful indicator species. They represent some of the most spectacular and visually appealing organisms in the world and play many vital roles in tropical ecosystems. We hope that this synthesis will lay the groundwork for future ecological studies of tropical butterfly populations, species, communities and conservation.  相似文献   

14.
Large mammal faunas in tropical forest landscapes are widely affected by habitat fragmentation and hunting, yet the environmental determinants of their patterns of abundance remain poorly understood at large spatial scales. We analysed population abundance and biomass of 31 species of medium to large-bodied mammal species at 38 Atlantic forest sites (including three islands, 26 forest fragments and six continuous forest sites) as related to forest type, level of hunting pressure and forest fragment size using ANCOVAs. We also derived a novel measure of mammal conservation importance for each site based on a “Mammalian Conservation Priority index” (MPi) which incorporates information on species richness, population abundance, body size distribution, conservation status, and forest patch area. Mammal abundance was affected by hunting pressure, whereas mammalian biomass of which was largely driven by ungulates, was significantly influenced by both forest type and hunting pressure. The MPi index, when separated into its two main components (i.e. site forest area and species-based conservation index Ci), ordered sites along a gradient of management priorities that balances species-focused and habitat-focused conservation actions. Areas with the highest conservation priority were located in semi-deciduous forest fragments, followed by lowland forests. Many of these fragments, which are often embedded within large private landholdings including biofuel and citrus or coffee crops, cattle ranches and pulpwood plantations, could be used not only to comply with environmental legislation, but also enhance the prospects for biodiversity conservation, and reduce edge effects and hunting.  相似文献   

15.
Our goal was to evaluate how avian assemblages varied along a gradient of urbanization in the highly fragmented landscape of coastal southern California. We measured species richness and abundance of birds within continuous blocks of habitat, within urban habitat fragments that varied in landscape and local habitat variables, and within the urban matrix at different distances from the wildland interface. These comparisons allowed us to characterize patterns of avifaunal response to a gradient of urban fragmentation. At the fragment scale, we found that fragment area was a strong, positive predictor of the total number of breeding species detected per fragment; total bird abundance per point count also increased with fragment size. Tree cover was higher in small fragments, as was the abundance of birds that typically occupy wooded habitats. Comparisons between core, fragment, and urban transects revealed differing patterns of response of individual bird species to urbanization. In unfragmented habitat, we recorded a relatively high diversity of urbanization-sensitive birds. In urban transects, these species were rare, and a relatively few species of non-native and anthropophilic birds were common. These urbanization-enhanced birds were also recorded in previous urban gradient studies in northern California and Ohio. Bird communities along the urban gradient reached their highest richness and abundance in fragments. The marked difference in vegetation structure between urban and natural landscapes in this arid shrubland system likely contributed to this pattern; the presence of native shrubs and exotic trees in fragments enabled both shrub and arboreal nesters to co-occur. As is characteristic of biotic homogenization, urban fragmentation in coastal southern California may increase local diversity but decrease overall regional avifaunal diversity.  相似文献   

16.
There is increasing evidence that local invertebrate populations persist only because of occasional immigration. Demands on land are so great that suites of reserves within the natural dispersal abilities of most species are unlikely to be obtained. Thus there may be little alternative to occasional reintroduction of stock if some species are to be preserved. Moreover, there may be occasions when a species is threatened with extinction due to destruction of its last habitats, and the absence of other suitable sites to which it could be transferred. In such cases there is a need to maintain stocks in captivity for use in future reintroductions. Indeed, this has been the approach followed by vertebrate conservationists, where the ideal of habitat conservation is often prohibitively expensive. Recent methods of rearing butterflies on artificial diets have allowed cost-effective production of large populations of butterflies and moths, even when their natural foodplant is unavailable. These populations may be considerably larger than their natural counterparts. Since it is more efficient to use resources to produce a number of species on one site, it is proposed that the maintenance of stocks of rare species be entrusted to a Captive Breeding Institute established for this purpose. Since the techniques employed have commercial potential in mass-production of species of economic importance, it is hoped that the Institute will be largely self-financing after its initial foundation. In this manner resources will not be diverted from the essential work of habitat conservation.  相似文献   

17.
A keystone species is one that is crucial in maintaining the organization and diversity of their ecological communities. We tested the idea that rabbits act as a keystone species in southern Europe by exploring relationships between rabbit abundance and the abundance and diversity of raptor species. At 20 sites in southern Spain we assessed rabbit abundance through counts of animals along transects and assessed the number of raptor individuals and species through watches from vantage points. In a further 120 locations we also derived an index of rabbit abundance, from pellets and compared this to the presence or absence of the critically endangered Spanish imperial eagle. Rabbit abundance was positively associated with the number of observations of raptors, the number of raptor species and the number of species of conservation concern. Sites with the most rabbits had higher conservation value. Moreover, the presence of Spanish imperial eagle was strongly associated with sites where rabbits were at high density. We conclude that rabbits do act as a keystone species and we suggest that conservation efforts should focus on improving the status of this small-game species in southern Europe.  相似文献   

18.
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19.
Butterfly assemblages were used to characterize and evaluate the conservation value of the main habitat types in the Aiguamolls de l’Empordà Natural Park (north-eastern Spain), an important protected wetland area on the Mediterranean coast. Butterfly data were obtained from a number of transects walked as part of the Catalan Butterfly Monitoring Scheme, which uses a standardized methodology for monitoring butterflies. A Mantel test indicated a strong association between habitat types and the composition of butterfly assemblages and a principal component analysis ordinated individual butterfly species along a gradient from woodland to open areas, thereby indicating various degrees of shade tolerance. In addition, cluster analysis distinguished two main groups of habitats based on the similarities of their butterfly fauna: woodland and bramble clumps and a group of three different kinds of grasslands (traditionally hay meadows, pastures, and alfalfa fields). Hay meadows flooded in winter (the so-called closes) appeared always as the highest ranked habitat in terms of conservation evaluation: they have more butterflies and a slight tendency to harbor more and generally rarer species. This conclusion coincides with that of previous investigations that have indicated that the most diverse and rare plant communities in the whole Natural Park are present in the closes, and highlights the importance of traditionally managed hay meadows for wildlife. However, these hay meadows - one of the rarest habitats in the Mediterranean region - are in alarming decline and have become the most threatened habitat in this protected area: no longer profitable, we believe that the future of the closes will depend ultimately on the existence of agri-environmental schemes.  相似文献   

20.
We tested whether the landscape occupancy and local population size of the monophagous butterfly Cupido minimus can be predicted by patch size and isolation of its host plant or by other habitat characteristics. C. minimus and its larval food plant Anthyllis vulneraria are classified as rare and endangered in northern Germany. Adults of C. minimus are ranked as the most sedentary butterfly species in northern Europe.Around the city of Göttingen (Germany), we checked all known locations of A. vulneraria (n=70) in June 2002 for butterfly eggs (in blooming flowerheads) and adult butterflies (within 20-min transects).We found eggs of C. minimus or a high number of adults (>7) in all habitats with A. vulneraria (which are calcareous grasslands) even when isolated up to 2-4 km. In multiple regression analyses, local population size of adult butterflies was positively related to the cover of its larval food plant A. vulneraria explaining 65% of variance. Cover of A. vulneraria increased with increasing habitat area and increasing cover of plant species in flower and decreased with increasing cover of shrub layer. Habitat isolation and further factors describing habitat quality were not related to C. minimus population size or cover of its larval food plant.The results suggest that dispersal ability of C. minimus is greater than expected and that management should focus to increase A. vulneraria patches. For conservation, low impact grazing once a year and removing of excessive shrubs in winter seems to be the most appropriate strategies.  相似文献   

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