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Vojtěch Jarošík Martin Konvi?ka Petr Pyšek Tomáš Kadlec Ji?í Beneš 《Biological conservation》2011,(1):490-499
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
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Magdalena Lenda Piotr Skórka Dawid Moroń Zuzanna M. Rosin Piotr Tryjanowski 《Biological conservation》2012,148(1):180-190
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
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Timothy C. Bonebrake Lauren C. Ponisio Carol L. Boggs Paul R. Ehrlich 《Biological conservation》2010,143(8):1831-1841
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
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Jennifer L. Hopwood 《Biological conservation》2008,141(10):2632-2640
Marginal habitats such as hedgerows or roadsides become especially important for the conservation of biodiversity in highly modified landscapes. With concerns of a global pollination crisis, there is a need for improving pollinator habitat. Roadsides restored to native prairie vegetation may provide valuable habitat to bees, the most important group of pollinators. Such roadsides support a variety of pollen and nectar sources and unlike agricultural fields, are unplowed, and therefore can provide potential nesting sites for ground-nesting bees. To examine potential effects of roadside restoration, bee communities were sampled via aerial netting and pan trapping along roadside prairie restorations as well as roadsides dominated by non-native plants. Management of roadside vegetation via the planting of native species profoundly affected bee communities. Restored roadsides supported significantly greater bee abundances as well as higher species richness compared to weedy roadsides. Floral species richness, floral abundance, and percentage of bare ground were the factors that led to greater bee abundance and bee species richness along restored roadsides. Traffic and width of roadside did not significantly influence bees, suggesting that even relatively narrow verges near heavy traffic could provide valuable habitat to bees. Restored and weedy roadside bee communities were similar to the prairie remnant, but the prairie remnant was more similar in bee richness and abundance to restored roadsides. Restoring additional roadsides to native vegetation could benefit pollinator conservation efforts by improving habitat on the millions of acres of land devoted to roadsides worldwide, land that is already set aside from further development. 相似文献
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《Biological conservation》1986,36(1):71-82
A survey of butterfly numbers on two plots of arable farmland in southern England in 1984 was carried out using the transect method of Pollard et al. (1975). On one plot the field edges were left unsprayed with pesticides (herbicides, fungicides and insecticides) from 1 January and on the other all fields were fully sprayed in accordance with normal farming practice. Sprayed and unsprayed transect sections were paired up according to adjacent field boundary habitat type.A total of 868 butterflies were recorded on the unsprayed plot compared to 297 on the sprayed plot. Of the 17 species recorded on more than one survey section, 13 were significantly more abundant on the unsprayed treatment. Butterfly species whose larval host plants occurred in unsprayed field edges showed slightly larger differences in number between treatments than species less able to breed in weedy cereal crops.The results suggest that pesticide use on cereal crops may reduce butterfly numbers and that arable farmland is a habitat in need of further study for butterfly conservation. 相似文献
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Traditionally, nature reserves have been centered mainly around areas that are important for vertebrate diversity. This practice has not gone unchallenged and may be a suboptimal choice for overall conservation planning. To investigate this problem, we sampled butterfly species richness in a nature reserve in north eastern Greece that was originally established for the protection of birds of prey. Patterns of butterfly species richness and abundance were investigated by means of transect walks across a range of the seven predominant habitat types (wet and dry meadow, pine, oak and mixed forest, grazed, and agricultural land). Data analysis, including ANOVA and DCA (detrended correspondence analysis), revealed that the main gradients in butterfly species richness (low to high) were from sites dominated by the pine forest matrix of the core areas of the reserve, to peripheral sites in landscapes of mixed or oak forest, and from sites with little human impact to more disturbed areas with high grazing pressure. Species of conservation interest were concentrated at sites of low human impact. Ten of them are endemic to Europe and/or threatened in Europe. In this respect, the most important species are Lycaena ottomanus, Thymelicus acteon, and Pseudophilotes vicrama which are declining all over Europe. Our results suggest that (1) traditional agricultural practices in areas surrounded by forest can be considered as important management tools in butterfly conservation, (2) highest butterfly species richness is found in the periphery of the reserve rather than in the core areas, and (3) for butterfly conservation the zones surrounding the strictly protected areas are equally important as the core areas. 相似文献
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Åke Berg Karin Ahrné Erik Öckinger Roger Svensson Bo Söderström 《Biological conservation》2011,144(12):2819-2831
Remaining patches of semi-natural grasslands are hot spots for biodiversity in modern agricultural landscapes. In Sweden semi-natural pastures cover approximately 500,000 ha. However, power-line corridors, road verges and clear-cuts cover larger areas (in total about 2,000,000 ha), and these open, less intensively managed habitats are potentially important for species associated with taller vegetation and flower resources (e.g. pollinating insects). The aim of the present study was to evaluate the relative importance of semi-natural pastures and the other three open habitats for butterflies in 12 forest-farmland mosaic landscapes in south central Sweden. Species composition differed significantly between habitats in multivariate analyses. Power-line corridors and semi-natural pastures harbored several species that were disproportionally abundant in these habitats (13 and 8 species, respectively), and power-line corridors also harbored several species that were classified as typical in indicator species analyses. There were more butterfly species, higher abundances and a tendency for more individuals of red-listed species in power-line corridors than in the other three habitats. Effects of the surrounding landscape composition seemed to be weaker than that of the local habitat. However, species composition was significantly associated with landscape composition and species with intermediate and low mobility were more abundant in forested landscapes than in landscapes dominated by arable fields. Analyses of flying time and host plants for larvae suggest that early flying species and species associated with dwarf shrubs were more common in power-line corridors than in the other habitats. A landscape perspective, which takes several habitats into account, is needed for conservation of butterfly communities in forest-farmland landscapes. Power-line corridors and road verges offer possibilities for creating habitats that are suitable for pollinating insects through conservation-oriented management. 相似文献
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Introduced species may impact native species and communities in many ways. One which has received relatively little attention is by serving as resources for natives, thereby altering their ecology. We address such impacts on the California butterfly fauna as currently understood. Eighty-two of California's approximately 236 butterfly species (34%) are reported as ovipositing or feeding on introduced plant taxa. Many more utilize introduced plants as nectar sources. Interactions with introduced plant taxa are not distributed evenly among butterfly species. Alpine and desert butterflies interact with relatively few introduced plants because few exotic plant species have reached and successfully colonized these habitats. Other California butterfly species are specialists on particular plant families or genera with no exotic representatives in California and have thus far failed to recognize any introduced plants as potential foodplants. Some California butterflies have expanded their geographic ranges and/or extended their flight seasons by feeding on exotic plants. However, negative impacts of exotic plant species can also occur. At least three of the state's butterfly species currently lay eggs on introduced taxa that are toxic to larvae. Impacts of introduced plant taxa on California's butterflies are expected to increase as both habitat conversion and alien introductions accelerate. 相似文献
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Disentangling effects of habitat diversity and area on orthopteran species with contrasting mobility
Loss of semi-natural grasslands and reduction of habitat diversity are considered major potential threats to arthropod diversity in agricultural landscapes. The main aim of this study was to investigate how area and habitat diversity, mediated by shrub encroachment after grassland abandonment, affect species richness of orthopterans in island-like grasslands, and how contrasting mobility might alter species richness response to both factors. We selected 35 isolated patches in landscapes dominated by arable land (durum wheat) in order to obtain two statistically uncorrelated gradients: (i) one in habitat area ranging from 0.2 to 55 ha and (ii) one in habitat diversity ranging from patches dominated by one habitat (either open grasslands or shrublands) to patches with a mosaic of different habitats. Habitat loss due to land-use conversion into arable fields was associated with a substantial loss of species with a positive species-area relationship (SAR), with sedentary species having a steeper and stronger SAR than mobile species. Halting habitat loss is, therefore, needed to avoid further species extinctions. Shrub encroachment, triggered by abandonment, presented a hump-shaped relationship with habitat diversity. An increase in habitat diversity enhanced species richness irrespective of patch area and mobility. Maintaining or enhancing habitat diversity, by cutting or burning small sectors and by reintroducing extensive sheep grazing into abandoned grassland, are suggested as complementary strategies to mitigate further decline of orthopteran diversity in the remnant patches. This would be equally important in both small and large patches. 相似文献
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Theory suggests that a disproportionate loss of species occurs when total habitat cover decreases to 10-30% of the landscape. To date, little empirical evidence has been collected to test for such thresholds in habitat cover, especially at the landscape scale. Here, we present empirical data on the species richness of woodland-dependent birds collected systematically from 24 landscapes (each 100 km2) that sample a gradient in habitat cover from <2% to 60%. To compare the relative effects of habitat cover and habitat configuration, landscapes with similar amounts of habitat but contrasting configuration (i.e., aggregated versus dispersed) were surveyed and the richness of woodland-dependent birds collated for each landscape. The relationship between species richness, habitat cover and habitat configuration was examined using analysis of co-variance (ANCOVA), multiple linear regression and univariate non-linear modelling. There was a significant effect of habitat cover (co-variate) in the ANCOVA, but the main treatment effect of configuration was not significant. However, comparison of non-linear models indicated that the shape of the response curve of species loss with decreasing habitat cover differed between aggregated and dispersed landscapes. Species richness was significantly related to habitat cover in all analyses, explaining between 55% and 60% of the variance in regression models. Mean patch shape complexity and the extent of habitat aggregation were also significant explanatory variables, but explained less than 10% of the variance in richness of woodland birds. Biogeographic variables (range in elevation and geographic location) explained up to 14% of the variance in species richness. There was strong evidence for a threshold response in species richness: non-linear models (broken-stick, exponential, inverse) exhibiting a sharp decline in species richness in landscapes with less than 10% habitat cover provided a better fit to the observed data than linear models. To our knowledge, this is the first empirical demonstration of landscape-level thresholds in species richness. We emphasise that thresholds in species richness denote multiple species’ extinction events, the end point of the process of species decline. For viable populations, habitat cover must be maintained well above the threshold level. Finally, thresholds of assemblage measures, such as species richness, potentially mask compositional changes in the avifauna community and may also conceal the loss of species with greater sensitivity to landscape change. 相似文献
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Urbanisation currently threatens over one-third of the world’s known amphibian species. The main threats of urbanisation to amphibian populations are habitat loss, habitat fragmentation and isolation, and degradation of habitat quality. A complex array of interacting biotic and abiotic factors impact amphibians in urban and urbanising landscapes. These can lead to a decrease in species richness and the abundance of individual species towards the centre of cities and towns. The ability of amphibians to disperse can be significantly reduced in urban and suburban landscapes. However, different species exhibit markedly different responses to urbanisation. Amphibian species that are habitat generalists or have relatively low dispersal requirements appear to be better able to survive in urban and suburban landscapes. There is insufficient information on the ecology of amphibians in urban and suburban areas, particularly in the tropics and sub-tropics, despite worldwide declines reported over past decades. Future research of amphibians in urban and suburban landscapes would greatly benefit by using long-term studies at sites along urban-rural gradients, conducted at both local and landscape scales. Research needs to be directed to the developing world in the tropics and sub-tropics, which has the highest rates of urbanisation. Research into amphibian ecology and conservation in the urbanising world would be improved through experimental approaches to determine the proximate causes of species’ responses to human modification of the landscape. Maintaining viable populations of amphibians in urban and suburban landscapes will require conservation strategies that consider key urbanisation processes (i.e. habitat availability and habitat quality) and the key responses and adaptations to urbanisation (i.e. species availability and species response). Conservation strategies for amphibians in urban and suburban landscapes need to include actions to prevent further loss and degradation of both terrestrial and aquatic habitat, and to reconnect the landscape to facilitate dispersal and long-term regional persistence of amphibian populations and communities. 相似文献
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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
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We report on a long-term study of the flower preferences of feeding adult butterflies undertaken in the Wyre Forest, UK. Examination of 5638 observations of nectar-feeding clearly demonstrates several findings: (i) that butterflies differ in their range of flower use, some are generalists and others specialists, respectively, exploiting more or less sources than expected; (ii) certain flower species are preferred over others. We find that (iii) generalism and specialism in flower use corresponds to generalism and specialism, respectively, in larval host range and biotope occupancy; that (iv) generalism in flower use is accounted for by life history and resource variables that increase opportunity for contact with a wider variety of flowering herbs; that (v) specialist flower users are more typically woodland butterflies and generalist flower users species of more open biotopes. A key finding is that (vi) many specialist flower users are butterfly species of conservation concern listed in Biodiversity Action Plans. We suggest that management of woodland sites for butterfly conservation should give as much consideration to nectar sources as to host plant sources. 相似文献
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Riparian zones are a characteristic component of many landscapes throughout the world and increasingly are recognised as key areas for biodiversity conservation. Their importance for bird communities has been well recognised in semi-arid environments and in modified landscapes where there is a marked contrast between riparian and adjacent upslope vegetation. The value of riparian zones in largely intact landscapes with continuous vegetation cover is less well understood. In this study, birds were surveyed at 30 pairs of riparian and adjacent non-riparian sites in extensive mesic forests of the Victorian Highlands, Australia. Riparian sites were floristically distinct from non-riparian sites and had a more complex vegetation structure, including a mid-storey tree layer mostly absent from non-riparian sites. Bird assemblages at riparian sites had significantly greater richness, abundance and diversity of species than was recorded at adjacent non-riparian sites. Species composition also differed significantly between these habitat types. Compositional differences in assemblages were due to a suite of distinctive species in each habitat and to significant contrasts in the densities of species that occurred in both habitat types. Many species (36%) attained a significantly greater abundance in riparian habitats. The distinctiveness and richness of the riparian avifauna contribute to the diversity of continuous forest landscapes. The spatial patterning of the avifauna, the occurrence of complementary assemblages, the presence of rare species and the potential for riparian habitats to serve as refuges, all point to the value of riparian zones and highlight the importance of landscape-level planning and management for avifaunal conservation. 相似文献
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In order to face the large and worrying biodiversity decline in agricultural landscapes, important policy instruments like agri-environmental schemes (AES) have been implemented. Studies that have examined the ecological effects of AES are now numerous and generally use indicators of biodiversity such as species richness and diversity as well as species abundance. Yet, it has been shown that simple metrics such as species richness or abundance may give misleading messages about biodiversity status and fate. Moreover, those indicators cannot detect another important source of biodiversity loss, biotic homogenisation. In this context, taking into account to a wider extent ecological difference among species would be more relevant, as well as focusing on the species specialisation which is known to be linked to higher species vulnerability. A bibliographic review investigating the criteria generally used to assess the success of AES showed that 55% of studies used species richness and/or abundance exclusively without any consideration of specialisation or other ecological traits in their evaluation of AES effectiveness. Based on data from the French breeding bird survey and studies at regional scale in France on farmland birds, we show that: (i) species richness and specialisation are generally negatively correlated in agricultural areas, (ii) habitat heterogeneity does not benefit specialist species, and (iii) monitoring of species diversity should be coupled with the monitoring of specialist species to improve conservation strategies in farming systems. Overall, this study emphasizes the need to account for both community richness and composition when assessing AES or similar conservation planning. 相似文献
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The influence of patch area and connectivity on avian communities in urban revegetation 总被引：1，自引：0，他引：1
Danielle F. Shanahan Craig Miller Hugh P. Possingham Richard A. Fuller 《Biological conservation》2011,(2):722-729
Landscape restoration through revegetation is being increasingly used in the conservation management of degraded landscapes. To effectively plan restoration programs information is required on how the landscape context of revegetation influences biodiversity gains. Here, we investigate the relative influence of patch area and connectivity on bird species richness and abundance within urban revegetation patches in Brisbane, Australia. We carried out bird surveys at 20 revegetation sites, and used hierarchical partitioning and model selection to test the relative importance of patch area (the area of revegetation including all directly connected remnant vegetation) and landscape connectivity (the vegetated area connected by less than 10 m, 20 m, 30 m, 40 m and 50 m cleared gaps). We controlled for a number of possible confounding variables within the hierarchical partitioning procedure. Both the hierarchical partitioning and model selection procedures indicated that connectivity had an important influence on bird species richness. Patch area in combination with connectivity were important influencing factors on overall bird abundance. We also carried out the hierarchical partitioning procedure for bird abundance data within a range of feeding guilds, yielding results specific to species groups. Overall our data suggest that greater connectivity enhances the habitat area that colonists can arrive from (resulting in greater species richness), whereas increased patch area allows for increased abundance by expanding the habitat available to species already present in a patch. A combined approach where connectivity and overall habitat area is enhanced across the landscape is likely to be necessary to meet long-term conservation objectives. 相似文献
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Organic farming often counteracts the decline of various taxa owing to agricultural intensification, but little is known about the relative importance of local management and landscape context for small mammals. We examined the abundance, species richness and diversity of small mammal communities in 22 organically and conventionally managed winter wheat fields pairwise located along a gradient of landscape structural complexity (41–94% arable land). Complex landscapes significantly increased small mammal abundance and (with marginal significance) species richness and diversity, but only in conventional fields, whereas organic farming increased small mammals in simple landscapes. These results indicate the importance of landscape complexity for small mammal populations in an intensified agriculture. Analyses at multiple spatial scales (100 m, 250 m, 500 m radii around focal fields), showed opposing responses of the three most abundant species to landscape complexity. Apodemus agrarius PALLAS abundance increased with increasing landscape complexity at a spatial scale of 100 m, whereas Microtus arvalis PALLAS and Sorex araneus L. abundances decreased with increasing landscape complexity at spatial scales of 100 m and 500 m, respectively, suggesting species-specific ecological needs as well as functional spatial scales for conservation management. In conclusion, agri-environmental measures for small mammals such as organic farming are most effective in simple landscapes, while complex landscapes presumably function as source habitats and can compensate for local agricultural intensification in conventional fields. 相似文献