首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
宋晓谕  刘玉卿  邓晓红  徐中民 《生态学报》2012,32(24):7722-7729
空间选择是生态补偿研究的核心问题之一,选择合理的区域进行生态补偿有利于提高生态补偿项目的效率.以黑河流域上游肃南县为研究区域,运用分布式水文模型Soil and Water Assessment Tool(SWAT)对研究区实施生态补偿后的水源涵养增加量进行模拟,同时考虑土地利用类型转化成本以及生态系统服务丧失风险,采用福利成本法对研究区生态补偿空间选择进行研究.结果表明:黑河上游肃南段内不同子流域的生态补偿效率系数最高值为0.0394,最低值0.0131,相差明显;根据效率系数,采用聚类分析方法,可将各子流域划分为优先补偿区、次级优先补偿区和潜在补偿区,分批进行补偿;采用空间选择后生态补偿效率较不采用时可提高54.5%.  相似文献   

2.
生态系统服务付费的诊断框架及案例剖析   总被引:1,自引:0,他引:1  
朱文博  王阳  李双成 《生态学报》2014,34(10):2460-2469
生态系统服务付费目前已成为生态系统服务研究的热点之一。参考Ostrom的社会-生态系统诊断框架,提取并总结影响生态系统服务付费执行效率的变量,建立了适合区域特点的项目绩效评估体系,并以哥斯达黎加(PSA)项目和中国退耕还林工程为例,探讨了该评估体系在生态系统服务付费效率诊断中的适用性。研究表明,依据该评估体系,未来中国在实施生态系统服务付费项目时应注意以下问题:建立生态系统服务付费的市场机制、实施多样化的付费方式;付费标准应考虑区域特征和供给方特征;建立生态系统服务付费项目的第三方监督和绩效评估机制;加强对生态系统服务的监测。  相似文献   

3.
Brazil faces an enormous challenge to implement its revised Forest Code. Despite big losses for the environment, the law introduces new mechanisms to facilitate compliance and foster payment for ecosystem services (PES). The most promising of these is a market for trading forest certificates (CRAs) that allows landowners to offset their restoration obligations by paying for maintaining native vegetation elsewhere. We analyzed the economic potential for the emerging CRA market in Brazil and its implications for PES programs. Results indicate a potential market for trading 4.2 Mha of CRAs with a gross value of US$ 9.2±2.4 billion, with main regional markets forming in the states of Mato Grosso and São Paulo. This would be the largest market for trading forests in the world. Overall, the potential supply of CRAs in Brazilian states exceeds demand, creating an opportunity for additional PES programs to use the CRA market. This expanded market could provide not only monetary incentives to conserve native vegetation, but also environmental co-benefits by fostering PES programs focused on biodiversity, water conservation, and climate regulation. Effective implementation of the Forest Code will be vital to the success of this market and this hurdle brings uncertainty into the market. Long-term commitment, both within Brazil and abroad, will be essential to overcome the many challenges ahead.  相似文献   

4.
This paper analyses poverty and inequality dynamics among smallholders along the Transamazon Highway. We measure changes in poverty and inequality for original settlers and new owners, contrasting income-based with multidimensional indices of well-being. Our results show an overall reduction in both poverty and inequality among smallholders, although poverty decline was more pronounced among new owners, while inequality reduction was larger among original settlers. This trend suggests that families have an initial improvement in livelihood and well-being which tends to reach a limit later—a sign of structural limitations common to rural areas and maybe a replication of boom and bust trends in local economies among Amazonian municipalities. In addition, our multidimensional estimates of well-being reveal that some economically viable land use strategies of smallholders (e.g., pasture) may have important ecological implications for the regional landscape. These findings highlight the public policy challenges for fostering sustainable development among rural populations.  相似文献   

5.
Conservation policies are emerging in many places around the world, many of which involve payment for ecosystem services (PES) schemes. PES schemes provide economic incentives for forgoing land uses that reduce the provision of ecosystem services. The efficiency of such schemes depends not only on the ecosystem services provided by an area but also on the willingness of local people to forgo their land use activities. Targeting land for enrollment in PES schemes on the basis of the potential provision of ecosystem services and on the willingness to forgo certain economic activities, may therefore improve the efficiency of these schemes. The objective of this study was to develop a targeting approach, based on three surrogates derived from remotely sensed and ancillary data, for identifying land to be enrolled in one of the largest PES schemes in the world: China's Grain-to-Green Program (GTGP). The GTGP encourages farmers to return steep hillside cropland to forest by providing cash, grain and tree seedlings. The three surrogates used in the targeting approach were slope index, cropland probability, and GTGP enrollment probability. Combining these surrogates through Bernoulli trials allows targeting areas under cropland, with low opportunity costs for farmers and with potentially high soil erosion and landslide susceptibility. Results of applying the targeting approach in a case study area (Baoxing County, Sichuan Province, China) show that around half of the land currently enrolled is placed in areas with gentle slopes and tend to be located distant from forest areas. This reduces the potential benefits obtained from the GTGP. Targeting land using the proposed approach may double the benefits obtained from the program under the same budget, thus improving its efficiency. The approach may be applied to the entire GTGP implementation area in China and with proper modifications it may also be applicable to similar PES programs around the world.  相似文献   

6.
We use economy-wide simulation methods to analyze the outcome of a simple REDD+ program in a mixed subsistence/commercial-agriculture economy. Alternative scenarios help trace REDD+’s causal chain, revealing how trade-offs between the program’s public and private costs and benefits determine its effectiveness, efficiency and equity (the 3Es). Scenarios reveal a complex relationship between the 3Es not evident in more aggregate analyses. Setting aside land as a carbon sink always influences the productivity of agriculture and its supply of non-market goods and services; but the overall returns to land and labor–which ultimately determine the opportunity cost of enrollment, the price of carbon and the distribution of gains and losses–depend on local conditions. In the study area, market-oriented landowners could enroll 30% of local land into a cost-effective program, but local subsistence demands would raise their opportunity costs as REDD+ unfurls, increasing the marginal cost of carbon. A combination of rent and wage changes would create net costs for most private stakeholders, including program participants. Increasing carbon prices undermines the program’s efficiency without solving its inequities; expanding the program reduces inefficiencies but increases private costs with only minor improvements in equity. A program that prevents job losses could be the best option, but its efficiency compared to direct compensation could depend on program scale. Overall, neither the cost nor the 3Es of alternative REDD+ programs can be assessed without accounting for local demand for subsistence goods and services. In the context of Mexico’s tropical highlands, a moderate-sized REDD+ program could at best have no net impact on rural households. REDD+ mechanisms should avoid general formulas by giving local authorities the necessary flexibility to address the trade-offs involved. National programs themselves should remain flexible enough to adjust for spatially and temporally changing contexts.  相似文献   

7.
Shared ecological knowledge about the impacts of biological invasions can facilitate the collective action necessary to achieve desired management outcomes. Since its introduction to an island archipelago in South America, the North American beaver has caused major changes to the ecosystem. We examined landowners’ mental models of how beavers impact ecosystem services in riparian areas to understand the potential to implement a large-scale eradication program. We used ethnographic interviews to characterize individual landowners’ perceptions about beaver-caused changes to ecosystems and landowners’ wellbeing, and examined the degree to which they are shared. While the eradication initiative focuses on ecosystem integrity, landowners considered impacts on provisioning services to be most salient. Landowners did not have a highly shared causal model of beaver impacts, which indicates a diverse knowledge system. This lack of consensus on how beavers impact riparian areas provides some optimism for garnering support for eradication, and also offers insights into challenges with mental modeling methodologies.  相似文献   

8.
Economic development and sustainable ecological and environmental development generally target different goals, and there are trade-offs and game-like behaviors between implementers and donors in reducing emissions from deforestation and degradation (REDD+) program. This paper analyzed the effects of evolutionary behaviors of REDD+ implementers and donors with respect to environmental service payments. Within a theoretical analysis framework, the evolutionary stable strategies of the implementers and donors under different contractual payments for ecosystem services (PES) scenarios are analyzed to explore contractual REDD+ payments through evolutionary game models. On this basis, anon-parametric local regression approach is used to analyze arrange of market-based contractual PES schemes in five REDD+ countries (Congo, Brazil, Ecuador, Nepal and Uganda). The results show the following: First, when the opportunity costs are less than the environmental benefits, some middle and high income developing countries are sufficiently incentivized to conserve forests, even without formal contractual PES scheme. This conservation occurs regardless of whether the industrialized countries will pay for the ecosystem services. Second, when the opportunity costs are greater than the environmental benefits, developing countries will generally not take the initiative to conserve forests when industrialized countries do not pay for the associated ecosystem services. Third, when there are enough contractual PES fines, developing countries will conserve forests, and the industrialized countries will pay for the ecosystem services. Finally, contractual PES fines are related to the costs of reducing emissions. Nepal has the largest marginal effect, and Uganda has the smallest. These results have implications for REDD+ program design and implementation: market-based contractual PES scheme should be given priority to regulate behavior of industrialized countries and developing countries in the PES scheme. Developing a targeted and differentiated contractual PES scheme requires an accounting of emission reduction costs in different countries.  相似文献   

9.
Many deer populations in Europe and North America have increased in abundance over the last decades. The increasing populations potentially entail both ecological and economic challenges and opportunities, but in practice we still know little about the extent to which these opportunities are being exploited in different management systems. The Norwegian red deer population has increased in density and expanded rapidly since the 1950s. Traditionally, red deer hunting has been undertaken by the local landowner and his relatives and friends. The present large population raises the question whether attracting other hunters could provide a higher economic return for the landowners and, if so, if they are interested in providing such hunting opportunities. We designed a survey to learn more about the landowners, both with respect to the present level of hunting income as well as economic costs of, for example, forest and agricultural damage; we also sought to understand their interest in increasing their income from red deer hunting and potential obstacles to realizing such an increased economic benefit. The results indicate that landowners on average think that red deer populations on their land result in higher costs than income but are nevertheless satisfied with the way things are. This highlights that increased numbers of deer need not automatically lead to more income for landowners and that the potential for income may be hindered by cultural factors such as reluctance to allow access to non-local hunters.  相似文献   

10.
Habitat loss and degradation have been identified as some of the main threats to breeding Curlew (Numenius arquata) across much of Europe. In Ireland, marginal habitats such as rough or wet grasslands and peatlands have been fragmented or degraded by activities including afforestation, drainage and intensification. The management implemented by landowners directly affects Curlew breeding territories. However, the values and perceptions held by landowners whose lands contain Curlew breeding territories, or the factors driving the decisions behind farming practices in these areas are rarely considered when looking at the causes of changes in these bird populations. This study, as part of the Curlew Conservation Programme established in 2017, gathered data through the distribution of questionnaires to landowners found within three kilometres of Curlew breeding territories in Ireland. In this study, we identify the current land uses being employed in Curlew breeding territories, and query future projections of land use in these areas. We investigate landowners’ perceptions of the requirements to sustain favourable environments for breeding Curlew. We also explore landowner values with respect to farming. The landowners in this study identified habitat loss and predation as the main drivers for Curlew declines. The majority of farming systems in this study were cattle rearing, the sustainability of which is under threat across Ireland. The results indicate that these landowners are not financially motivated, however, the availability of financial aid and expert advice are listed by landowners as requirements for traditional farming practices to continue. These results give an insight to the lifestyle, values and perceptions owners of land adjacent or within Curlew breeding territories. This information can be used to design Curlew conservation programmes that align with these values.  相似文献   

11.
In this paper, I examine patterns of wealth accumulation and their influence on deforestation among smallholders at Uruará and Redenção, in the state of Pará in the Brazilian Eastern Amazon. I argue that the development of the smallholder economy has not been a linear process, and the diversity of smallholder farming systems and their patterns of wealth accumulation have varied implications for the rate and magnitude of deforestation. However, whilst there are differential impacts of farming practices on deforestation—cattle ranching has a greater impact than cash cropping or subsistence agriculture—the stronger correlate of deforestation is the wealth of the farmers. Wealthier farmers not only tend to deforest more in absolute terms, but also show a slightly greater propensity to deforest whatever their production system. Though cattle production is a key driver of wealth accumulation and thus deforestation, a significant number of smallholders adopt diversified production systems. The main factors explaining the relationship between the farming systems and deforestation were years of residence on the lot, distance of the lot to main market and the amount of day labor hired—and not variables describing household structure.  相似文献   

12.
Brazil has presided over the most comprehensive agrarian reform frontier colonization program on Earth, in which ~1.2 million settlers have been translocated by successive governments since the 1970’s, mostly into forested hinterlands of Brazilian Amazonia. These settlements encompass 5.3% of this ~5 million km2 region, but have contributed with 13.5% of all land conversion into agropastoral land uses. The Brazilian Federal Agrarian Agency (INCRA) has repeatedly claimed that deforestation in these areas largely predates the sanctioned arrival of new settlers. Here, we quantify rates of natural vegetation conversion across 1911 agrarian settlements allocated to 568 Amazonian counties and compare fire incidence and deforestation rates before and after the official occupation of settlements by migrant farmers. The timing and spatial distribution of deforestation and fires in our analysis provides irrefutable chronological and spatially explicit evidence of agropastoral conversion both inside and immediately outside agrarian settlements over the last decade. Deforestation rates are strongly related to local human population density and road access to regional markets. Agrarian settlements consistently accelerated rates of deforestation and fires, compared to neighboring areas outside settlements, but within the same counties. Relocated smallholders allocated to forest areas undoubtedly operate as pivotal agents of deforestation, and most of the forest clearance occurs in the aftermath of government-induced migration.  相似文献   

13.
Deforestation and conversion of native habitats continues to be the leading driver of biodiversity and ecosystem service loss. A number of conservation policies and programs are implemented—from protected areas to payments for ecosystem services (PES)—to deter these losses. Currently, empirical evidence on whether these approaches stop or slow land cover change is lacking, but there is increasing interest in conducting rigorous, counterfactual impact evaluations, especially for many new conservation approaches, such as PES and REDD, which emphasize additionality. In addition, several new, globally available and free high-resolution remote sensing datasets have increased the ease of carrying out an impact evaluation on land cover change outcomes. While the number of conservation evaluations utilizing ‘matching’ to construct a valid control group is increasing, the majority of these studies use simple differences in means or linear cross-sectional regression to estimate the impact of the conservation program using this matched sample, with relatively few utilizing fixed effects panel methods—an alternative estimation method that relies on temporal variation in the data. In this paper we compare the advantages and limitations of (1) matching to construct the control group combined with differences in means and cross-sectional regression, which control for observable forms of bias in program evaluation, to (2) fixed effects panel methods, which control for observable and time-invariant unobservable forms of bias, with and without matching to create the control group. We then use these four approaches to estimate forest cover outcomes for two conservation programs: a PES program in Northeastern Ecuador and strict protected areas in European Russia. In the Russia case we find statistically significant differences across estimators—due to the presence of unobservable bias—that lead to differences in conclusions about effectiveness. The Ecuador case illustrates that if time-invariant unobservables are not present, matching combined with differences in means or cross-sectional regression leads to similar estimates of program effectiveness as matching combined with fixed effects panel regression. These results highlight the importance of considering observable and unobservable forms of bias and the methodological assumptions across estimators when designing an impact evaluation of conservation programs.  相似文献   

14.
Abstract: In areas with dense landownership patterns, management of white-tailed deer (Odocoileus virginianus) depends upon collective decision making of landowners and hunters. To resolve conflicts associated with this commons dilemma, wildlife management associations (WMAs) have become a popular mechanism for coordinating wildlife management decisions in private land states, especially in Texas, USA. Social capital, represented by metrics such as trust, reciprocity, and community involvement, has been identified as an important determinant of the success of collaborative institutional arrangements. To determine the influence of social capital on the effectiveness of WMAs, we address 2 research questions: 1) do WMAs exhibit elements of social capital, and 2) what landowner characteristics affect elements of social capital within WMAs? We used a mail survey questionnaire to determine the effect of various factors on the activities and management practices in 4 WMAs in 2 regions in Texas: the Lower Post Oak Savannah (LPOS) and the Central Post Oak Savannah (CPOS). The LPOS landowners were members of larger associations, had generally acquired their land more recently, held more frequent meetings, and tended to have longer association membership than CPOS landowners, yet they exhibited lower social capital. The CPOS landowners owned significantly larger properties, and were predominantly absentee wealthy males that considered relaxation and hunting more important land uses than property ownership for a place to live. The smaller group size of the CPOS associations may be the most important factor in building and maintaining social capital. Intra-association trust, a primary measure of social capital, was positively influenced by the longevity of property ownership, the number of association meetings, the percentage of males in the association, and other factors. Conversely, negative influences on trust included absentee ownership and the proportion of woodland habitat present in each WMA. We suggest that deer are a common-pool resource whose populations are dependent upon collective action by stakeholders. Social capital building within landowner associations could facilitate the sustainable harvest of quality deer and possibly lead to cooperative management of other common-pool natural resources.  相似文献   

15.
This study considers a biosocial explanation of why johns, the purchasers of commercial sex exchanges, are almost exclusively male. Trivers's theory of parental investment and sexual selection predicts that differential parental investment by biological sex will lead to divergent sex-based reproductive instincts. The sex bearing the larger parental investment will tend to be choosier whereas the sex bearing the lesser investment will tend to be relatively indiscriminate and competitive for access to sexual resources. We hypothesized that men are more likely than women to offer objects of value in exchange for access to sexual resources. Using self-reports of sex-purchasing from Add Health data (N = 14,544), we found that maleness was a robust predictor of john behavior even after controlling for well-known criminogenic risk factors.  相似文献   

16.
The availability of high quality data on the distribution and abundance of British birds at the national scale means that this fauna is the basis for a growing body of macroecological study. Nevertheless. questions remain about how representative of wider patterns the distributions and abundances of birds in Britain may be. Here, we use data on the British. European and global breeding distributions of British birds to show that species that are widespread in Britain also tend to be widespread across larger regions. These results hold for both residents and migrants separately, and when controlling for the phylogenetic related ness of species. Species with wide latitudinal spans in Europe also tend to have large British ranges, with the largest British ranges exhibited by species inhabiting mid-latitudes in Europe. These results demonstrate that the distributions of birds within Britain are not simply idiosyacratic. but do reflect aspects of their broader distributions.  相似文献   

17.
Some urbanising rural (i.e. ‘amenity’) landscapes have seen an increase in forest cover over recent decades. Small-acreage landowners are key stakeholders in this forest recovery and its future ecological trajectory. Using 17 qualitative case-studies of small-acreage properties located in the Noosa hinterland in south-east Queensland, this study explores the types and condition of forests on these properties, the landholder’s differing forest management perspectives, practices and outcomes, and the implications for local biodiversity conservation. The properties contained a diverse mix of managed and un-managed natural and planted forests. Invasive weed species were a common component. Protecting and enhancing the ecological values of amenity landscapes will require an increase in active, best-practice forest management on small-acreage properties. Small-acreage landowners will require greater access to labour support and other subsidised resources to implement recommended practices. Such practices include controlling and reducing the spread of invasive weeds and soil erosion, reducing fire hazards, and positively influencing the rate and pathway of succession in regrowth forests. Peer-mentoring programs incorporating guided tours of ‘model’ small-acreage forests, and supporting landowners to establish their own small native plant nurseries and engage with local community nurseries (i.e. supplying seeds, volunteering labour), could help to increase small-acreage landowners’ forest management interests, knowledge, skills and activity. Long-term cooperative, cross-boundary forest management projects with on-going monitoring and adaptive management guided or implemented by skilled professionals are needed in amenity landscapes, particularly to increase the success of restoration interventions in weed-dominated regrowth forests. There is also a need for long-term socio-ecological analyses of amenity landscapes’ diverse and evolving small-acreage forests to better inform their future management.  相似文献   

18.
Human induced pluripotent stem cells (iPSCs) have been shown to have promising potential for regenerative medicine and tissue engineering applications. In the present study, osteogenic differentiation of human iPSCs was evaluated on polyethersulfone (PES) nanofibrous scaffold. According to the results, higher significant expressions of common osteogenic-related genes such as runx2, collagen type I, osteocalcin and osteonectin was observed in PES seeded human iPSCs compared with control. Alizarin red staining and alkaline phosphatase activity of differentiated iPSCs demonstrated significant osteoblastic differentiation potential of these cells. In this study biocompatibility of PES nanofibrous scaffold confirmed by flattened and spreading morphology of iPSCs under osteoblastic differentiation inductive culture. Taking together, nanofiber-based PES scaffold seeded iPSCs showed the highest capacity for differentiation into osteoblasts-like cells. These cells and PES scaffold were demonstrated to have great efficiency for treatment of bone damages and lesions.  相似文献   

19.
Global conservation discourses and practices increasingly rely on market-based solutions to fulfill the dual objective of forest conservation and economic development. Although varied, these interventions are premised on the assumption that natural resources are most effectively managed and preserved while benefiting livelihoods if the market-incentives of a liberalised economy are correctly in place. By examining three nationally supported payment for ecosystem service (PES) schemes in Vietnam we show how insecure land tenure, high transaction costs and high opportunity costs can undermine the long-term benefits of PES programmes for local households and, hence, potentially threaten their livelihood viability. In many cases, the income from PES programmes does not reach the poor because of political and economic constraints. Local elite capture of PES benefits through the monopolization of access to forestland and existing state forestry management are identified as key problems. We argue that as PES schemes create a market for ecosystem services, such markets must be understood not simply as bald economic exchanges between ‘rational actors’ but rather as exchanges embedded in particular socio-political and historical contexts to support the sustainable use of forest resources and local livelihoods in Vietnam.  相似文献   

20.
One intracerebral passage of either the parent egg seed (PES) or an attenuated variant (10t) of the Trinidad strain of Venezuelan equine encephalomyelitis (VEE) virus in young adult mice produced progeny that were no longer differentiated unequivocally on the basis of plaque size. Plaques averaging about 2 mm in diameter, which was somewhat smaller than those formed by the PES virus and larger than those of the 10t strain, were formed by both strains. Seven serial passages of the PES virus in mouse brain failed to alter its virulence appreciably. In contrast, passage in mouse brain progressively changed the properties of the attenuated 10t strain. A substrain was isolated that possessed virulence similar to that of the PES virus and formed small plaques similar to those of the 10t strain. These findings showed a unique dissociation between the plaque size and virulence of the 10t strain. The new substrain differed from the PES virus and the 10t strain in its capacity for growth in mouse tissues after intraperitoneal inoculation. The substrain multiplied poorly in splenic tissue, which supports growth of the PES and 10t strains, but grew to high titers in the brain, which does not support appreciable growth of the 10t strain.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号