共查询到20条相似文献,搜索用时 10 毫秒
1.
Forest vegetation of a Protected Area (Askot Wildlife Sanctuary) in Kumaun (west Himalaya) was analysed for structure, composition and representativeness. A high percentage of non-natives was noticed in herbaceous flora of all representative forest types. Floristic representativeness in all growth forms (tree, shrub and herbs) increased significantly (tree, p<0.05; shrub and herbs, p<0.01) with altitude. The population structures of trees suggest, (i) expansion of riverine and Pinus roxburghii forests; (ii) compositional changes in Quercus leucotrichophora and Quercus lanuginosa forests, largely owing to preferred extraction demand of inhabitants; and (iii) infrequent regeneration and declining population of Quercus semecarpifolia and Abies pindrow forests. The possible pathways of non-native introduction in the study area were examined. Considering the existing status of forest vegetation and future trends, proliferation of non-native species in most forest types was discussed. It is suggested that the compositional changes vis-a`-vis proliferation of non-native species need priority attention while initiating conservation activities in the reserve. 相似文献
2.
Vegetation mapping and nature conservation: a case study in Terceira Island (Azores) 总被引:1,自引:0,他引:1
In order to emphasize the importance of vegetation mapping for nature conservation purposes a case study in Terceira island (Azores) is presented, in which the importance of the natural vegetation of the eastern slope of Santa Bárbara volcano (which is part of the Site of Community Importance of Santa Bárbara–Pico Alto) is evaluated through the elaboration of its vegetation map. Fourteen (14) different natural vegetation types were identified: grasslands (1 type), peat bogs (2 types), scrubs (2), forests (5), successional vegetation (3) and vegetation of rocky slopes (1). All communities are protected under the Habitat and Species Directive (EC/92/43) and most of them are endemic to the Azores Islands. This fact, together with the significant number of Azorean endemic taxa (18), Macaronesian endemic taxa (5) and species protected under the Habitat and Species Directive (7), gives this area an important conservation value that justifies future protection actions. Vegetation mapping is an important tool for the characterization, evaluation and implementation of managing plans of natural areas of the Azores islands. The use of a floristic-based classification, supported by multivariate analysis and structural data, is an efficient methodology for the construction of these maps. The data collected comprise an important set of information about the distribution and abundance of natural vegetation types and endemic and rare species. This information was not available until now and is indispensable for the elaboration of management plans of Special Zones for Conservation that will be part of the NATURA 2000 network. 相似文献
3.
L. M. Wedding A. M. Friedlander J. N. Kittinger L. Watling S. D. Gaines M. Bennett S. M. Hardy C. R. Smith 《Proceedings. Biological sciences / The Royal Society》2013,280(1773)
Increases in the demand and price for industrial metals, combined with advances in technological capabilities have now made deep-sea mining more feasible and economically viable. In order to balance economic interests with the conservation of abyssal plain ecosystems, it is becoming increasingly important to develop a systematic approach to spatial management and zoning of the deep sea. Here, we describe an expert-driven systematic conservation planning process applied to inform science-based recommendations to the International Seabed Authority for a system of deep-sea marine protected areas (MPAs) to safeguard biodiversity and ecosystem function in an abyssal Pacific region targeted for nodule mining (e.g. the Clarion–Clipperton fracture zone, CCZ). Our use of geospatial analysis and expert opinion in forming the recommendations allowed us to stratify the proposed network by biophysical gradients, maximize the number of biologically unique seamounts within each subregion, and minimize socioeconomic impacts. The resulting proposal for an MPA network (nine replicate 400 × 400 km MPAs) covers 24% (1 440 000 km2) of the total CCZ planning region and serves as example of swift and pre-emptive conservation planning across an unprecedented area in the deep sea. As pressure from resource extraction increases in the future, the scientific guiding principles outlined in this research can serve as a basis for collaborative international approaches to ocean management. 相似文献
4.
This paper discusses the role of microbial resource collections in the ex situ conservation of microbial diversity and, in particular, the activities of a recently completed Darwin Initiative project to facilitate collection, identification and exploitation of Indonesian microbial diversity. This helped revitalize the collection of the Lembaga Ilmu Pengetahuea Indonesia (Indonesian Institute of Sciences), LIPI, Research and Development Centre for Biology, Bogor, Indonesia. It is suggested that a focus on microorganisms beneficial to man is essential to enable ex situ collections to be a useful tool in the conservation and sustainable utilization of microbial diversity. This task is enormous and far beyond the capabilities of one collection and its achievement will necessitate a network of collections. 相似文献
5.
J. M. Wójcik A. Kawako M. Tokarska M. Jaarola P. Vallenback & C. Pertoldi 《Journal of Zoology》2009,277(1):81-87
A free-living population of European bison Bison bonasus in the Białowieża Primeval Forest originated from only seven founder animals after a severe bottleneck that occurred at the beginning of the 20th century. Consequently, the contemporary population of the species is characterized by low genetic diversity. We studied a total of 195 individuals (127 males and 68 females). A 1429 bp fragment of mitochondrial DNA (mtDNA) including the D-loop region was analyzed in 87 individuals and revealed only three distinct haplotypes. Nucleotide ( π ) and haplotype ( H d ) diversity values were estimated for the European bison and were compared with π and H d estimated from three individuals of American bison Bison bison . Very low diversity values were found in the European bison in comparison with the diversity values found in the American bison. The low mtDNA variability in the European bison is in concordance with theoretical expectations for a species that has undergone a severe and recent bottleneck. A management strategy for the preservation of the rare and very rare haplotypes present in the Białowieża population of the European bison is discussed. Furthermore, all 195 individuals were investigated for heteroplasmy involving these three haplotypes, in order to detect a possible association between heteroplasmy and the incidence of males affected by posthitis , a disease that affects the male reproductive organs, leading to necrotic lesions. Heteroplasmy was found in 15 females, in 17 males affected by posthitis and in 11 non-affected males, and no significant association was found. 相似文献
6.
Gregor Kozlowski Sandra Bürcher Matthieu Fleury Fanny Huber 《Biodiversity and Conservation》2009,18(3):649-662
The purpose of this study was to examine the composition, distribution, ecology, and conservation status of the Atlantic elements
of the Swiss flora. About 195 Atlantic and 80 Mediterranean–Atlantic vascular plant species of the European flora have been
used as the basis for our analysis. The complete list of 3,143 taxa has been used as the reference for the Swiss flora. The
distributions of the species are illustrated in coincidence maps based on the computer database of the Data Centre of the
Swiss Flora in Geneva, Switzerland. Our study demonstrates clearly that the Atlantic flora of Europe requires a new biogeographical
appraisal. The Swiss flora comprises 66 Atlantic and Mediterranean–Atlantic taxa, which are taxonomically and ecologically
highly diverse. Switzerland contains 44% of all European Sub-Atlantic plants. This confirms the Sub-Atlantic geographical
position of Switzerland. Only one Eu-Atlantic species growing in Switzerland, Vicia orobus, can be classified as native with certainty. This species is critically endangered and merits the highest conservation priority.
Although a very alpine country, Switzerland has a relatively large number of Mediterranean–Atlantic species. The Atlantic
and Mediterranean–Atlantic plants are a very threatened group in Switzerland, with wetland plants the most imperilled ecological
group.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
Currently 177 vascular plant species are known or presumed to be obligately associated with water in Peru. Their composition and diversity were surveyed in relationship to their distributions among the natural regions of Peru. Despite considerable aridity, the coastal plains of Peru have important aquatic ecosystems, including marshes in river deltas and mangroves in the far north, near the border with Ecuador; 70 species of aquatic plants are found in this coastal region. The Andean highlands include a great variety of wetlands, plus lakes and rivers; 62 species are found, including eight species of Isoetes, some of which are potentially threatened by extinction. The Amazon region of Peru includes both steep montane rivers in the headwaters and wide floodplains formed by meandering rivers in the lowlands; 102 species are found distributed among these ecosystems, although many additional species are semi-aquatic. Research and conservation strategies for Peru's aquatic plants need to take into account these important regional differences. 相似文献
8.
1. The empirical relationships among body size, species richness and number of individuals may give insight into the factors controlling species diversity and the relative abundances of species. To determine these relationships, we sampled the arthropods of grasslands and savannahs at Cedar Creek, MN using sweep nets (90 525 individuals of 1225 species) and pitfall traps (12 721 individuals of 92 species). Specimens were identified, enumerated and measured to determine body size.
2. Both overall and within abundant taxonomic orders, species richness and numbers of individuals peaked at body sizes intermediate for each group. Evolution could create unimodal diversity patterns by random diversification around an ancestral body size or from size-dependent fitness differences. Local processes such as competition or predation could also create unimodal diversity distributions.
3. The average body size of a species depended significantly on its taxonomic order, but on contemporary trophic role only within the context of taxonomic order.
4. Species richness ( Si ) within size classes was related to the number of individuals ( I i ) as S i = I i0·5 . This relationship held across a 100 000-fold range of body sizes. Within size classes, abundance distributions of size classes were all similar power functions. A general rule of resource division, together with similar minimum population sizes, is sufficient to generate the relationship between species richness and number of individuals.
5. Smaller bodied species had slightly shallower abundance distributions and may, in general, persist at lower densities than larger species.
6. Our results suggest there may be fewer undescribed small arthropod species than previously thought and that most undescribed species will be smaller than arthropods. 相似文献
2. Both overall and within abundant taxonomic orders, species richness and numbers of individuals peaked at body sizes intermediate for each group. Evolution could create unimodal diversity patterns by random diversification around an ancestral body size or from size-dependent fitness differences. Local processes such as competition or predation could also create unimodal diversity distributions.
3. The average body size of a species depended significantly on its taxonomic order, but on contemporary trophic role only within the context of taxonomic order.
4. Species richness ( S
5. Smaller bodied species had slightly shallower abundance distributions and may, in general, persist at lower densities than larger species.
6. Our results suggest there may be fewer undescribed small arthropod species than previously thought and that most undescribed species will be smaller than arthropods. 相似文献
9.
Laura A. Nunes Samuel T. Turvey James Rosindell 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2015,370(1662)
The combination of rapid biodiversity loss and limited funds available for conservation represents a major global concern. While there are many approaches for conservation prioritization, few are framed as financial optimization problems. We use recently published avian data to conduct a global analysis of the financial resources required to conserve different quantities of phylogenetic diversity (PD). We introduce a new prioritization metric (ADEPD) that After Downlisting a species gives the Expected Phylogenetic Diversity at some future time. Unlike other metrics, ADEPD considers the benefits to future PD associated with downlisting a species (e.g. moving from Endangered to Vulnerable in the International Union for Conservation of Nature Red List). Combining ADEPD scores with data on the financial cost of downlisting different species provides a cost–benefit prioritization approach for conservation. We find that under worst-case spending $3915 can save 1 year of PD, while under optimal spending $1 can preserve over 16.7 years of PD. We find that current conservation spending patterns are only expected to preserve one quarter of the PD that optimal spending could achieve with the same total budget. Maximizing PD is only one approach within the wider goal of biodiversity conservation, but our analysis highlights more generally the danger involved in uninformed spending of limited resources. 相似文献
10.
Rustic coffee plantations are characterised by the use of numerous wild and cultivated tree species for providing shade to the coffee shrubs. This paper analyses the role of these plantations in wild tree conservation through the examination of their patterns of floristic variation in southern Mexico. The studied plantations included a total of 45 plant species, most of which were wild tree species, including both mature forest and pioneer taxa. An extrapolation of the species accumulation curve among stands indicated that the whole system, composed of more than 100 coffee plantations, may harbour as many as 34 species of wild trees. The floristic structure of rustic coffee plantations was highly variable. This variation is a result of a combination of factors such as human management, original stand cover and the asynchrony in development stage of different plantations. This promotes a large -diversity in the system. Thus, although a single plantation may have a limited potential to preserve wild tree species, it is the whole ensemble of floristically heterogeneous plantations which renders this agroforestry system valuable for plant diversity conservation, particularly in a region where native forest vegetation has almost disappeared. 相似文献
11.
Optimizing resiliency of reserve networks to climate change: multispecies conservation planning in the Pacific Northwest,USA 总被引:1,自引:0,他引:1
The effectiveness of a system of reserves may be compromised under climate change as species' habitat shifts to nonreserved areas, a problem that may be compounded when well‐studied vertebrate species are used as conservation umbrellas for other taxa. The Northwest Forest Plan was among the first efforts to integrate conservation of wide‐ranging focal species and localized endemics into regional conservation planning. We evaluated how effectively the plan's focal species, the Northern Spotted Owl, acts as an umbrella for localized species under current and projected future climates and how the regional system of reserves can be made more resilient to climate change. We used the program maxent to develop distribution models integrating climate data with vegetation variables for the owl and 130 localized species. We used the program zonation to identify a system of areas that efficiently captures habitat for both the owl and localized species and prioritizes refugial areas of climatic and topographic heterogeneity where current and future habitat for dispersal‐limited species is in proximity. We projected future species' distributions based on an ensemble of contrasting climate models, and incorporating uncertainty between alternate climate projections into the prioritization process. Reserve solutions based on the owl overlap areas of high localized‐species richness but poorly capture core areas of localized species' distribution. Congruence between priority areas across taxa increases when refugial areas are prioritized. Although core‐area selection strategies can potentially increase the conservation value and resilience of regional reserve systems, they accentuate contrasts in priority areas between species and over time and should be combined with a broadened taxonomic scope and increased attention to potential effects of climate change. Our results suggest that systems of fixed reserves designed for resilience can increase the likelihood of retaining the biological diversity of forest ecosystems under climate change. 相似文献
12.
Biodiversity conservation in a fast-growing metropolitan area in China: a case study of plant diversity in Beijing 总被引:1,自引:0,他引:1
Guangmei Wang Gaoming Jiang Yunlong Zhou Quanru Liu Yanshou Ji Shixiong Wang Shengbin Chen Hui Liu 《Biodiversity and Conservation》2007,16(14):4025-4038
As the capital of China, Beijing has experienced extensive urbanization in the past two decades. To explore the effect of
urbanization on plant diversity, we investigated the vascular plant diversity of the whole Beijing Municipality in three different
functional (urban, suburban and exurban) regions. For its geo-diversity, Beijing has a rather abundant vascular plant diversity
(2,276 species), including 207 species of conservation concern such as endemic, threatened and protected species. The exurban
region had not only the highest species diversity (1,998 species), but also the most species of conservation concern (194
species). Urban region possessed the maximum alien species in terms of both absolute number and proportional representation,
while the suburban region had the least species diversity (1,026 species). Some problems, such as wetland shrink and biological
invasions, were common in the whole Beijing Municipality. However, primary threats to biodiversity differed in the three functional
regions. The urban and suburban regions mainly suffered from habitat loss and fragmentation due to urban sprawl, while the
exurban region faced serious ecosystem degradation from increasing disturbance from both local and urban people. Based on
our investigation, we put forward conservation strategies for the three regions: improving the structure and ecological function
of green spaces in urban region, preserving as much remnant natural habitats in the suburban region, and restricting the rural
tourism and establishing a biosphere reserve in the exurban region. In addition, improving public education and orientating
that more to social aspects of conservation practice is strongly recommended. 相似文献
13.
Priority areas for the conservation of South African vegetation: a coarse-filter approach 总被引:1,自引:0,他引:1
B. Reyers D. H. K. Fairbanks A. S. Van Jaarsveld M. Thompson 《Diversity & distributions》2001,7(1-2):79-95
Abstract. South Africa has an important responsibility to global biodiversity conservation, but a largely inadequate conservation area network for addressing this responsibility. This study employs a coarse-filter approach based on 68 potential vegetation units to identify areas that are largely transformed, degraded or impacted upon by road-effects. The assessment highlights broad vegetation types that face high biodiversity losses currently or in the near future due to human impacts. Most vegetation types contain large tracts of natural vegetation, with little degradation, transformation or impacts from road networks. Regions in the grasslands, fynbos and forest biomes are worst affected. Very few of the vegetation types are adequately protected according to the IUCN's 10% protected area conservation target, with the fynbos and savanna biomes containing a few vegetation types that do achieve this arbitrary goal. This investigation identifies areas where limited conservation resources should be concentrated by identifying vegetation types with high levels of anthropogenic land use threats and associated current and potential biodiversity loss. 相似文献
14.
The rich biodiversity repository of the Niger Delta region of Nigeria is under severe threat from diverse sources such as
deforestation, inadequate farming practices, invasive alien species, urbanization and oil and gas exploration and development
activities. This biodiversity “hot spot” is the second most sensitive environment in Africa. The over 70 Protected Areas (PAs)
here have lost substantial portions of their area which translates to loss of biodiversity. The need to select representative
sites within each of the ecological zones of the region for effective and sustainable biodiversity conservation is, therefore,
essential. Vital site criteria that have ecological, socio-economic and cultural dimensions were selected and assessed through
a combination of relevant scientific information, indigenous traditional knowledge and participatory rural appraisal (PRA)
to yield Key Biodiversity Areas (KBAs).They are significantly different from the site selection criteria and principles used
in the UK and to a large extent adopt the critical factors that underscore biodiversity conservation in a largely primary
production based economy such as in much of the developing world. The three sites selected for biodiversity conservation through
this process yielded not only community buy-in but also participatory action and ownership, which are critical for the sustainability
of the biodiversity conservation efforts. Shell Nigeria and World Wide Fund (WWF) representatives are already concluding plans
to commence effective conservation projects in the selected sites. This approach is hereby advocated for consideration and
adoption for the preservation of the remaining stock of the unique biodiversity in developing countries. 相似文献
15.
Webb TJ Gaston KJ Hannah L Ian Woodward F 《Proceedings. Biological sciences / The Royal Society》2006,273(1587):757-765
The dynamic relationship between vegetation and climate is now widely acknowledged. Climate influences the distribution of vegetation; and through a number of feedback mechanisms vegetation affects climate. This implies that land-use changes such as deforestation will have climatic consequences. However, the spatial scales at which such feedbacks occur remain largely unknown. Here, we use a large database of precipitation and tree cover records for an area of the biodiversity-rich Atlantic forest region in south eastern Brazil to investigate the forest-rainfall feedback at a range of spatial scales from ca 10(1)-10(4) km2. We show that the strength of the feedback increases up to scales of at least 10(3) km2, with the climate at a particular locality influenced by the pattern of landcover extending over a large area. Thus, smaller forest fragments, even if well protected, may suffer degradation due to the climate responding to land-use change in the surrounding area. Atlantic forest vertebrate taxa also require large areas of forest to support viable populations. Areas of forest of ca 10(3) km2 would be large enough to support such populations at the same time as minimizing the risk of climatic feedbacks resulting from deforestation. 相似文献
16.
17.
To maintain biodiversity conservation areas, we need to invest in activities, such as monitoring the condition of the ecosystem, preventing illegal exploitation, and removing harmful alien species. These require a constant supply of resources, the level of which is determined by the concern of the society about biodiversity conservation. In this paper, we study the optimal fraction of the resources to invest in activities for enhancing the social concern y(t) by environmental education, museum displays, publications, and media exposure. We search for the strategy that maximizes the time-integral of the quality of the conservation area x(t) with temporal discounting. Analyses based on dynamic programming and Pontryagin’s maximum principle show that the optimal control consists of two phases: (1) in the first phase, the social concern level approaches to the final optimal value y∗, (2) in the second phase, resources are allocated to both activities, and the social concern level is kept constant y(t)=y∗. If the social concern starts from a low initial level, the optimal path includes a period in which the quality of the conservation area declines temporarily, because all the resources are invested to enhance the social concern. When the support rate increases with the quality of the conservation area itself x(t) as well as with the level of social concern y(t), both variables may increase simultaneously in the second phase. We discuss the implication of the results to good management of biodiversity conservation areas. 相似文献
18.
In Situ conservation of maize in Mexico: Genetic diversity and Maize seed management in a traditional community 总被引:2,自引:0,他引:2
Results from a study of maize varieties and seed sources in a traditional community in Jalisco, Mexico, raise questions about the relationship between genetic erosion and the introduction of varieties. The relevance of models for in situ conservation of crop genetic resources based on geographical isolation of a community is discussed. The morphophenological diversity of local materials is shown to be enhanced by introductions of both improved cultivars and landraces from farmers in other communities. On the other hand, the geographical point of reference for defining “local” landrace is shown to be larger than the community itself. Farmers will classify seed obtained from other farmers in and outside the community as that of a local landrace if it resembles their own according to the phenotypic characteristics they use to distinguish varieties. Maize diversity in this community is then the result of a certain level of introduction of genetic material and not of geographical isolation. 相似文献
19.
海南岛生物多样性保护优先区评价与系统保护规划 总被引:4,自引:0,他引:4
选择海南岛140个濒危物种为指示物种,在物种栖息地评价的基础上,利用系统保护规划工具MARXAN模型进行迭代运算,提出了海南岛生物多样性保护优先区域,并对保护优先区进行评价.结果表明:海南岛保护优先区面积5383.7km2,占海南岛陆地面积的15.6%,集中分布于鹦哥岭、尖峰岭、五指山等林区和北部湿地;在保护优先区中,11个I级指示物种栖息地的保护比例均超过各自栖息地总面积的65%.通过对保护优先区与现有自然保护区的空缺分析,建议扩充尖峰岭保护区群、鹦哥岭-黎母山保护区群、五指山-吊罗山保护区群;新建抱龙林场-林鼻岭-福万岭保护体系;在海南岛北部建立以水源保护为主,同时兼顾珍稀物种保护的水源地保护带. 相似文献
20.
Measuring bee and wasp community habitat preferences in natural systems may provide insights for biodiversity management and
conservation as habitat heterogeneity can be the major factor affecting species diversity in a community. Here, we present
evidence that supports the use of a vegetation structure-based approach in order to predict the occurrence of common Brazilian-remnant
solitary bee and wasp species. Using trap nests, we sampled Aculeate bees and wasps in a forest remnant within an urban area
of southeast Brazil. We also measured eight habitat structure components in the area. Tree trunk circumference, shrub and
wood log abundance were good predictors of presence or absence of the commonest solitary bee and wasp species in the study
area. We demonstrated that even on a small scale it is possible to detect significant influences of habitat structural features
on species occurrences and that some of them are effective as surrogates for predicting trap-nesting Hymenoptera occurrence
in a given area. Our data present evidence on the potential application of a habitat structure-based approach in conservation
assessments concerning cavity-nesting Hymenoptera. We caution, however, that this habitat structure-based approach must to
be taken with prudence as a detailed survey of an area’s biodiversity is always preferable. 相似文献
