共查询到20条相似文献,搜索用时 15 毫秒
1.
Human exploitation can have severe conservation implications for wildlife populations. In the Serengeti ecosystem, Tanzania, illegal hunting is a serious concern for wildlife management, and in this study we investigated if density, demography and behaviour can be used as indicators of human exploitation. We used impala ( Aepycerus melampus) as a model species to study human exploitation inside and outside a strictly protected area. Over a six month period, a total of 2050 km of transects were driven in the different protected areas (National Park, Game Reserve, Open Area). Densities were estimated by using distance sampling and the partially protected areas were found to have significantly lower densities (4.3 ind/km 2) than the National Park (15.3 ind/km 2). A variation in density between different sections within the National Park was also found. However, we found no differences in group sizes. Moreover, the sex-ratio was more skewed towards females in the partially protected areas and in sections within the National Park close to villages. In addition, impalas showed higher alertness levels, and longer flight initiation distance to an approaching human in the partially protected areas compared to the National Park. The present harvest levels by illegal hunting in the study area are most likely the cause of the observed differences. Our results suggest that density, demography and behaviour can be used as indicators of human exploitation, but that this probably varies according to local hunting pressure. Furthermore, it could be expected that the results obtained in this study might reflect the state of other ungulates in the area, which raises concern whether management objectives for the buffer zones of Serengeti National Park are met. 相似文献
2.
Recognizing the importance of preserving biodiversity and ecosystem services, human society has established extensive protected area networks to conserve these resources in recent decades. Are protected areas working as expected? Empirical coarse-scale assessments of this question across large regions, or even globally, tend to answer “yes”, while fine-scale studies of individual protected areas often and repeatedly answer “no”. We conducted a first fine-scale analysis of Brazil’s extensive Amazonian protected area network (1.8 million km 2) and have quantitatively estimated conservation effectiveness in light of changing human development pressures in the surrounding landscape. The overall network maintained intact forest cover for 98.6% of protected forest lands, largely agreeing with previous coarse-scale studies. However, detailed examination of 474 individual protected areas unveils a broad range of efficacy. Many protected areas (544,800 km 2) experience default protection simply due to their remoteness. Many others (396,100 km 2) have provided highly effective protection in the face of substantial human development pressure. Conversely, 12% (38) of protected areas have failed to protect the 27,300 km 2 that they encompass, and another 7% (23) provide only marginal protection of 37,500 km 2. Comprehensive landscape assessments of protected area networks, with frequent monitoring at scales matching the patterns of human-caused disturbances, are necessary to ensure the conservation effectiveness and long term survival of protected areas in rapidly changing landscapes. The methods presented here are globally adaptable to all forested protected areas. 相似文献
3.
Given the importance placed on protected areas, determining their effectiveness in representing and maintaining biodiversity is a core issue in conservation biology. Nonetheless, frameworks identifying the breadth of issues associated with this effectiveness, and case studies of how well these are understood in particular regions, remain lacking. In this paper, we provide such a framework and an overview of the current state of knowledge of the ecological effectiveness of protected areas in the United Kingdom. Arguably, better data are available to address such issues in this region than anywhere else in the world. Nonetheless, studies remain scarce and have focussed foremost on the, rather narrow, issue of the effectiveness of management actions on individual sites in order to deliver fixed conservation objectives and discharge statutory responsibilities. Some attention has also been paid to how well the regional collection or portfolio of protected areas performs, particularly in capturing biodiversity features. Work on the extent to which protected areas in the United Kingdom form effective functional networks is in its infancy, but initiatives are under development. We identify some of the questions about the effectiveness of protected areas to which answers need to be known at the site, portfolio and network levels, and how significant progress might be achieved in addressing these. 相似文献
4.
Canada is dominated by remote wilderness areas that make important conservation contributions, but are currently only protected de facto by their inaccessibility. Mechanisms for the identification and formal protection of such areas can help ensure that they continue to function naturally and provide essential ecosystem services. However, a lack of spatially explicit, publicly available sources of data on anthropogenic disturbances and natural resource extraction challenges the development of detailed wilderness inventories. We suggest that landscape structure can be used to classify areas of natural landscapes, as trained by the landscape structure of protected areas, and demonstrate this approach by mapping de facto protected areas in Canada’s boreal forest. Overall, between 50%, based on landscape structure, and 80%, based on anthropogenic infrastructure alone, of Canada’s boreal zone exists in large, intact blocks. The true extent of boreal wilderness likely falls within this range, as existing infrastructure datasets may omit disturbance and the protected area network in far northern areas proved inadequate to train effective wilderness classifications. We anticipate that such efforts may be improved by refining the identification of training areas or by classifying along additional landscape metrics. Nevertheless, the areas identified are valuable candidates for protected area expansion, and can contribute to a reserve network that meets national and regional conservation targets and is representative of the range of vegetation productivities, which was used as a biodiversity surrogate. Our general approach need not be limited to the boreal forest, as it has the potential to successfully identify relatively undisturbed (or less disturbed) areas over a range of systems and across levels of human influence. 相似文献
5.
In Ghana, budgetary allocations for protected area management have been consistently low. To improve cost-effectiveness and performance of law enforcement, monitoring feedback was used to provide the foundation for informed management decisions. Between 2004 and 2006, a system to monitor staff performance, patrol effort, illegal wildlife use, and trends in large-mammal populations was established in seven protected areas. In two national parks, where GIS-based monitoring systems were in place, in the course of 2006, data were standardised and analysed in the same way. Encounters on patrol with illegal activities and large mammals were corrected for patrol effort and the size of the area to enable comparing encounter rates in different protected areas. In December 2005, law-enforcement performance was evaluated in six protected areas. Through dissemination of the evaluation report, the poor performance of patrol staff and high levels of illegal activity in five out of six sites entered the public domain, and created a spirit of competition between protected areas. The present evaluation showed that in the course of 2006, in the six sites evaluated, patrol performance improved by 59% on average, compared to only 11% in the two parks that were not evaluated. In the four savannah sites evaluated, poaching was reduced by 72%, but only by 17% in the two forest sites evaluated. This compares with a reduction in poaching of 33% in the two parks. Patrol data were open to several types of error. Although reliability of patrol data was checked at different hierarchical levels, the final check was at headquarters in Accra, comparing seasonal fluctuations in large-mammal encounters with those in two control areas. 相似文献
6.
We examined the response of bird communities to a gradient of human impact in the Adirondack Park of northern New York State by testing the relationship of land use management types to an Index of Biotic Integrity (IBI) across the Adirondack landscape. We created the IBI by placing birds into 12 different guild categories and scoring study blocks according to relative representation of specialist versus generalist guild types. We investigated three questions relating to the effects of land use management on biotic integrity in the Adirondacks: (1) are there differences in biological integrity among the major land use types; (2) if so, what characteristics of these land use types are associated with high integrity bird communities; and, (3) to what degree is land management regulation effective in maintaining biological integrity in the Adirondack Park? We found significant differences in total, functional, compositional, and structural integrity on five land use types ranging from hamlet to wilderness. In all cases, integrity was lowest in hamlet areas and increased along the gradient to its highest level in wilderness areas.Biotic integrity showed strong groupings of the five land use classes. We found that bird community integrity was strongly related to roadlessness and that birds primarily responded to the distinction between developed and undeveloped land types. In contrast to roads and human development, forest management impacts in the Adirondacks do not appear to be of a high enough intensity to have significant negative impacts on breeding bird community integrity. Clustering of development is a means by which integrity may be safeguarded for the long term in the Adirondack Park. 相似文献
7.
Declining trends in the integrity of freshwater systems demand exploration of all possible conservation solutions. Freshwater protected areas have received little attention, despite the prominence of protected areas as conservation interventions for terrestrial and more recently marine features. We argue that a dialogue on freshwater protected areas has been neglected both because few models of good protected area design exist, and because traditional notions of protected areas translate imperfectly to the freshwater realm. Partly as a result of this conceptual disconnect, freshwaters have been largely ignored in protected area accounting schemes, even though a number of existing freshwater conservation strategies could qualify according to general protected area definitions. Rather than impose terrestrially-motivated ideas about protected areas onto freshwaters, we propose new vocabulary - freshwater focal area, critical management zone, and catchment management zone - that can be used in conjunction with IUCN protected area categories and that recognize the special ecological dynamics of freshwaters, and in particular the critical role of fluvial processes. These terms, which attempt to diffuse concerns about locking away essential ecosystem goods and services, move us toward consideration of protected areas for freshwaters. This conceptual shift, which acknowledges that freshwater conservation may occur remotely from freshwater features, opens the door for improved integration of freshwater, terrestrial, and marine concerns in protected area design and management. 相似文献
8.
Interactions among sympatric large predators and their prey and how they respond to conservation measures are poorly known. This study examines predictions concerning the effects of establishing a protected area in Nepal on tigers ( Panthera tigris), leopards ( Panthera pardus), and their ungulate prey. Within a part of the park, after 22 years the total density of wild ungulates had increased fourfold, to ca. 200 animals/km 2, almost exclusively due to a remarkable increase in chital deer ( Axis axis). Tiger density also increased markedly to nearly 20 animals/100 km 2, whereas leopard density did not and was ca. 5 animals/100 km 2. The prediction that grazers should increase more than browsers was only partially supported. The prediction of positive density dependence in prey selection was not supported. Instead, the most abundant species (chital and hog deer, Axis porcinus) were killed less frequently than expected, whereas the lower-density wild boar ( Sus scrofa) was preferred. Predictions that (i) initially rare species suffer highest predation was partially supported, that (ii) predation is highest among the most abundant prey was not supported, and that (iii) predation is highest among the most preferred prey independently of their densities was supported. Clearly, the conservation efforts adopted in Bardia were successful, as both tigers and their natural prey base increased. However, the positive numerical response of tigers limited and depressed the abundance of some prey species. Thus, conservation activities aimed at restoring large predators are likely to change in the composition of the overall mammal community, potentially eliminating rare but preferred prey species. 相似文献
9.
We present a procedure for the selection of a network of reserves representing the biological diversity of a large and biologically poorly known region. The quantitative analysis gives equal weighting to a wide array of different species: mobile and sessile, long-lived and ephemeral, heterothermic and homeothermic, etc. Sampling was based on quadrats that were positioned through the region using a stratified random strategy. This provided a presence-absence matrix of the species composition at each quadrat. Numerical pattern analysis was used to identify 14 species assemblages and to re-order the sites and species in the data matrix. The geographic pattern of each assemblage throughout the region was described by contouring assemblage richness, the isolines being the proportion of the number of species in each assemblage. The data matrix was re-examined. Some assemblages exhibit several gradients in species composition. For example, a 0·1 isoline in the east may represent a different 10% of species than a 0·1 isoline in the west. Other assemblages exhibit only a single gradient in species composition. The results were used to select the optimum positions of reserves needed to represent the compositional diversity of each of the 14 species assemblages. Limited field checking confirmed the predicted isolines in assemblage compositional richness to a satisfactory extent. 相似文献
10.
本文以位于胶东半岛中部山区的栖霞市为例,在对整个研究区进行流域提取的基础上,分别统计各流域内的景观指数,并通过聚类分析对整个栖霞市的山区景观进行分区。首先解译2010年Thematic Mapper(TM)遥感影像数据,获得栖霞市景观格局图,以1︰25 000地形图为基础数据源,建立DEM模型,利用ArcGIS水文分析模块将研究区划分为300个子流域。然后根据常用景观格局指数所反映的生态学意义和景观特征信息,并结合研究区内的具体景观结构,选择边缘密度(ED)、多样性指数(SDI)、斑块大小变异系数(PSCOV)、面积加权平均分维数(AWMPFD)和核心区密度(CAD)5个景观指数,并结合各流域的平均高程与空间分布对每一个子流域进行景观格局分析,探讨各子流域景观格局的空间差异,揭示人类活动、自然干扰等各种景观生态机制对区域景观生态的影响。研究结果为:ED值和CAD值随着海拔的增加而逐渐变大,垂直分异特征明显;SDI值呈现出由低海拔向高海拔逐步减少的趋势;PSCOV值随海拔的增加呈现出类似倒"U"形曲线;AWMPFD值不具有明显的垂直分异特征。最后将这5个指数进行聚类分析,同时利用流域主体景观类型对栖霞市进行景观格局分区,各土地利用类型被划分为3个景观生态类型区。研究结果为:一类区面积最小(10.14%),该区域是农作物种植的稳定农业区,景观结构和规模都很稳定,需要继续保护;二类区面积最大(50.93%),各种景观类型呈现空间交错分布,斑块形状复杂,属于自然景观和人文景观的过渡区域,需要加强该区域的土地规划和产业合理布局;三类区面积较大(35.92%),主要集中在中高海拔区域,林地和草坡地居多,开垦难度较大。分区结果能够较好地反映研究区景观生态结构的显著特征与空间分异状况,对栖霞市的土地管理和规划具有一定的指导意义。 相似文献
11.
This paper briefly reviews the present status of the Italian National Parks and other protected areas. Nature conservation is still rather weak in Italy and the likely causes of this are pointed out and discussed. Inadequate boundaries, hostility of park inhabitants, speculation by promoters, insufficient support by the State and by the Regional Governments badly affect all National and Natural Parks. This may depend partly on historical factors and partly on the lack of State interest and public opinion on nature preservation. On the other hand, there are a few signs that this situation is slowly becoming better and the management of the Parks has noticeably improved during the last five years. The activity of associations such as the World Wildlife Fund has been of particular importance in stimulating public opinion and in protecting valuable areas. 相似文献
12.
Climate and land-use changes are expected to cause many species to shift into or beyond the boundaries of protected areas, leading to large turnover in species composition. Here, we tested whether long-established protected areas in Canada were more robust to such climate change impacts than areas with no formal protection by measuring changes in modeled butterfly species distributions ( n = 139) within them. We used a recently established distribution modeling technique, Maxent, to model butterfly species’ distributions in two epochs (1900-1930 and 1960-1990). We compared rates of butterfly species richness and composition change within protected areas against distributions of randomly selected, ecologically similar, but non-protected, areas. Change in species richness and composition within protected areas were, for the most part, the same as changes observed among random areas outside protected area boundaries. These results suggest that existing protected area networks in Canada have provided little buffer against the impacts of climate change on butterfly species richness, possibly because land-use change surrounding long-standing protected areas has not been substantial enough to elevate the habitat protection afforded by these protected areas relative to other areas. Although protected areas are unarguably beneficial in conserving biological diversity, their capacity to maintain habitat appears insufficient to prevent broader-scale climate changes from sweeping species beyond their boundaries. 相似文献
13.
Many protected area (PA) systems have developed in response to socio-economic and aesthetic criteria and need to be modified to increase their conservation value. National gap analyses are an important step in describing and addressing this problem, so we sought to determine the representativeness of English PAs devoted to biodiversity conservation by using Natural Areas (NAs), elevation and PA boundary data. We found that National Nature Reserves (NNRs) and Sites of Special Scientific Interests (SSSIs) cover only 6.3% of England and are generally small, with respective median areas of 1.1 and 0.2 km 2. The English PA system under-represents lowland areas and provides a median level of 2.5% protection for the NA types, with seventy nine per cent of NA types having less than 10% protection. Therefore, we suggest that England's PA system needs to be expanded, although this would probably entail modification of existing legislation to increase involvement by landowners. We also compare our results with previous appraisals that used species distribution record data and suggest that landscape-level analyses may give a more accurate and less positive assessment. 相似文献
14.
Aquatic ecosystems are connected over large spatial scales, have varied drivers, strong and often conflicting societal interests and interacting management processes. Many of the world’s protected areas (>100,000, ∼12% of land) include freshwater ecosystems, some specifically declared for freshwater protection, but often supplied by rivers outside their protected boundaries. Such complex socio-ecological systems have considerable challenges. We report on Strategic Adaptive Management (SAM), a management framework that should be implemented, irrespective of resourcing, in protected areas of any river system, ranging from heavily managed or regulated through to pristine rivers. We briefly outline the four stages of the SAM process for aquatic protected areas and present three case studies from South Africa and Australia in different stages of SAM implementation. Progress is incremental, reflecting gaps, problems, and socio-ecological dynamism. Real-world implementation usually means such management is passive although experimentation with environmental flows remains possible. While maturity in SAM is incremental over years or decades, it can and should be applied even if environmental problems are urgent and contentious. The stages of SAM should produce an agreed vision and/or mission among stakeholders, with an appropriate hierarchy of objectives that determines indicators to be measured, allowing ongoing reflection, learning and adaptation. There is no panacea for achieving aquatic conservation, but Strategic Adaptive Management offers hope with its interlinked processes for navigating complexity and learning. SAM in freshwater conservation is progressing because of the imperative for sustainability, history of interaction between scientists and managers and the need for transdisciplinary governance of rivers. 相似文献
15.
Protected areas (PAs) are the cornerstone of global conservation efforts but their performance in maintaining populations of their key species remains poorly documented. Here, we address this gap using a new database of 583 population abundance time series for 69 species of large mammals in 78 African PAs. Population abundance time series were aggregated to form a multi-species index of overall change in population abundance. The index reveals on average a 59% decline in population abundance between 1970 and 2005. Indices for different parts of Africa demonstrate large regional differences, with southern African PAs typically maintaining their populations and western African PAs suffering the most severe declines. These results indicate that African PAs have generally failed to mitigate human-induced threats to African large mammal populations, but they also show some successes. Further development of our index could help to measure future progress towards post-2010 targets for reducing biodiversity loss. 相似文献
16.
We applied six measures of effectiveness to recent decisions about additional conservation areas in north-eastern New South Wales. Three have been widely used previously: (1) number of conservation areas; (2) total extent of conservation areas; and (3) representativeness (the proportion of natural features such as forest types or animal species represented in conservation areas to some targeted level). The other measures were: (4) efficiency or representation bias (the extent to which some features are protected above target levels at the expense of others that remain poorly protected); (5) relative protection of vulnerable areas within public land (percentage protection of flat, fertile areas relative to that of steep and/or infertile areas); and (6) relative protection of vulnerable areas across all tenures (the correlation between the amount of protection given to features and their vulnerabilities to clearing). We applied the measures in two chronological comparisons: the reserve system in 1994, 1996 and 1997; and before and after the Interim Assessment Process of 1996 which involved negotiations over new reserves and extensive unreserved areas that were temporarily deferred from logging. Over the study period, despite expansion of formal conservation and progress towards quantitative conservation targets, gazetted reserves remained strongly biased to the steep and/or infertile parts of public lands. Both gazetted reserves and areas deferred from logging increased the bias in protection away from forest types most vulnerable to clearing and for which regional conservation targets had already been most compromised. Two major challenges for future conservation decisions in the region are common to conservation planning generally: (1) to focus protection within public tenure on habitats and species most vulnerable to threatening processes such as logging; and (2) to provide more effective conservation management on private lands where loss of native vegetation continues. 相似文献
17.
The establishment and maintenance of a system of protected areas is central to regional and global strategies for the conservation of biodiversity. The current global trend towards human population growth and widespread environmental degradation means that such areas are becoming increasingly isolated in fragmented habitat islands. In regions in which this process is well advanced a high proportion of species are thus predicted to have become restricted to protected areas. Here using uniquely detailed datasets for Britain, a region with close to the global level of percentage coverage by statutory protected areas, we determine the extent of restriction of Red List vascular plant species of conservation concern to these areas. On the basis of currently known distributions, overall our results strongly support the importance of a dual conservation strategy in Britain, in which protected areas are maintained with particular reference to those biodiversity features (such as many threatened plant species) that are highly dependent on them, and in which components of the wider landscape are also managed in such a way as to promote the abundance and distribution of such features with particular reference to those which are unlikely to persist in protected areas alone. 相似文献
18.
Problems and correlates of success in the conservation of Africa’s rain forests were evaluated for 16 protected areas in 11 countries, representing approximately half of all protected areas in this biome. Data were obtained from questionnaires, published and unpublished accounts, and direct observations. Despite numerous problems, all protected areas conserved indigenous rain forest biodiversity more effectively than did alternative land uses. More than half the protected areas suffered extensive ecological isolation. Effective management of protected areas was seriously compromised by inadequate funding and government support. Dense human populations, often resulting from immigration, constituted major threats to protected areas. Perceived conservation success was greatest for large protected areas surrounded by similar habitat with strong public support, effective law enforcement, low human population densities, and substantial support from international donors. Contrary to expectations, protected area success was not directly correlated with employment benefits for the neighboring community, conservation education, conservation clubs, or with the presence and extent of integrated conservation and development programs. Studies are needed to better understand what shapes positive pubic attitude towards protected areas because none of the conventional public outreach programs were correlated with public attitude. We also identify apparent deficiencies in foreign assistance to these protected areas. The single most important short-term strategy was considered to be the improvement of law enforcement effectiveness through greater technical and financial support. Nine medium-term strategies are identified, including provision of adequate and secure long-term funding, establishing research and monitoring programs, and developing more appropriate conservation and development programs. Long-term strategies deal with two ultimate causal factors, mainly attitudes and value systems, and stabilizing human populations. Future success of Africa’s protected areas is contingent upon long-term international assistance including contingencies mandating realistic performance standards. 相似文献
19.
The significance of reserves in maintaining forest bird species of conservation concern ( N = 36) was studied by large-scale quantitative line transect bird censuses in Finland, which stretches 1100 km through the boreal zone from the hemiboreal to the subarctic. Altogether 12 245 km of line transect was carried out in 1981-2004 in reserves covering 28 910 km 2. Bird census data in protected areas were combined into 100 km × 100 km squares. As a group the studied bird species were rather evenly distributed throughout the reserve network. The present reserve network is particularly significant for species having their highest densities in northern Finland, because large proportions of the populations of these species occurred in protected areas. However, over half of the studied species were concentrated in protected areas of southern and central Finland, and only small proportions of their populations were included in the present reserve network. In contrast to the whole species pool of conservation concern, the studied individual forest bird species were not distributed evenly throughout the whole reserve network. This suggests that for most individual species a regionally concentrated network is a preferred option, but for the whole species group the reserve network should clearly be regionally complementary and representative even in the boreal zone, where species have rather wide ranges. Thus, only some species and their habitats can be preserved in a spatially uneven reserve network in boreal forests. 相似文献
20.
The Central African Republic (CAR) has made an impressive commitment to biodiversity conservation, with a total of 15 protected areas covering about 10.9% of the country. This study critically examines the status of these protected areas in light of their potential for long-term protection of biodiversity. First of all, the protected area system does not protect a representative sample of the ecoregions of the CAR. Even more important is the fact that only 32% of the protected areas are adequately managed. Law-enforcement is inadequate, and poaching poses the largest threat to biodiversity conservation. Given the dim economic prospects, the CAR will need continued financial as well as technical assistance to deal with protected area management. Experiences have shown that such intervention can make a difference. However more attention needs to be given to capacity building, long-term funding mechanisms, regional collaboration and political commitment to make such interventions sustainable in the long-term. 相似文献
|