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 687 毫秒
1.
In the Andes, demand for water is growing and upland land-use changes are increasing. Water quality, quantity and seasonal flow have thus also become environmental services with potential monetary value. Yet, currently the region's pioneer PES schemes are not paying for measured environmental services, but for proxy land uses thought to provide the(se) service(s). Hydrological modeling makes explicit the tacit causal relationships and tests underlying assumptions. Ideally, when combined with an economic analysis of land-use alternatives, this could inform decision makers on how much to pay for different interventions in different spatial locations. This paper focuses on two Andean watersheds: Moyobamba (Peru) and Pimampiro (Ecuador). In the first case, a municipal water company is preparing a payment for environmental services (PES) scheme to reduce upstream sediment loads. In the second, a similar conservation-oriented municipal PES scheme has operated since 2000, but the hydrological linkages have never been tested. Applying the Soil & Water Assessment Tool (SWAT), we identify in both watersheds biophysically critical areas for service delivery, and compare services for current land uses with change scenarios: deforestation, reforestation, live barriers, and agroforestry. We then use the ECOSAUT optimization model to predict net economic benefits for service providers. In Moyobamba, switching to shade-grown coffee would halve sediment yields, and increase significantly farmers’ economic benefits. This requires high up-front investment, but the willingness to pay of water users in Moyobamba town may suffice to cover the upfront costs. In Pimampiro, resumed deforestation would increase sediments by >50% and reduce dry-season flow by 0.5%, thus reinforcing the rationale of the existing PES scheme, focused on conserving native forests and grasslands.  相似文献   

2.
We review the current status of experimental studies in India to understand the linkages between afforestation and hydrology. This discipline deals with the use and management of water, social awareness of environmental problems, and ecosystem limitations on provision of watershed services by river basins in the mountain regions of India. Our review begins with examination of experimental works in tropical countries and proceeds to discussion of initiatives of Indian research institutes and Government organizations towards establishing experimental watersheds to understand the impacts of land cover changes on hydrologic regimes in the Indian sub-continent. This is followed by the review of the experimental work carried out by various authors to assess the impact of land cover changes on major water balance components such as, runoff, groundwater, evapotranspiration and sediment yield. The spatial scales of these experiments have been limited to small watersheds or field plots. This paper also describes impacts of human interventions (such as planta- tions of exotic forest species to restore degraded landscapes) on the water balance components in diverse hydro-geo-environmental conditions in the Indian sub-continent. We focus on identifying the research areas which require immediate attention to develop tools to assist planners and policy makers in assessing and managing the water resources in these complex environments. The review is largely based on research results reported during the last 20 to 30 years.  相似文献   

3.
Biologically mediated soil processes rely on soil biota to provide vital ecosystem services in natural and managed ecosystems. However, land use changes continue to impact on assemblages of soil biota and the ecosystem services they provide. The objective of the present study was to assess the effect of land use intensification on the distribution and abundance of soil invertebrate communities in the Nilgiri, a human-dominated biosphere reserve of international importance. Soil invertebrates were sampled in 15 land use practices ranging from simple and intensively managed annual crop fields and monoculture tree plantations through less intensively managed agroforestry and pristine forest ecosystems. The lowest taxonomic richness was found in annual crops and coconut monoculture plantations, while the highest was in moist-deciduous and semi-evergreen forests. With 21 ant species, agroforestry systems had the highest diversity of ants followed by forest ecosystems (12 species). Earthworms and millipedes were significantly more abundant in agroforestry systems, plantations and forest ecosystems than in annual crop fields. Ants, termites, beetles, centipedes, crickets and spiders were more abundant in forest ecosystems than in other ecosystems. It is concluded that annual cropping systems have lower diversity and abundance of soil invertebrates than agroforestry and natural forest ecosystems. These results and the literature from other regions highlight the potential role that agroforestry practices can play in biodiversity conservation in an era of ever-increasing land use intensification and habitat loss.  相似文献   

4.
The rapidly increasing area of tree plantations, especially in the tropics and subtropics, has raised expectations and concerns as to their impact on ecosystem services. We studied the effect of the establishment of eucalyptus and pine plantations on local people's social valuations of ecosystem services in a case study in Uruguay. We also assessed the social and political restrictions that might limit the establishment of new markets for ecosystem services. Our study showed that the rapid change in land use in Uruguay over the past 20 years, from grassland to plantations, has affected people's perceptions of landscape's capacity to produce ecosystem services. The ecosystem services of plantations that showed the greatest discrepancy between local people's valuations and both recognition by experts and current scientific evidence were biodiversity, water effects, and carbon cycling. We found that in particular regulating services, and some provisioning ones, are quite well recognized by substance specialists, but are sometimes rather unfamiliar to the general public. The proper planning of plantations may improve the provision of ecosystem services, such as biodiversity enhancement, wood availability for fire and energy, water quality, and carbon sequestration, while at the same time diluting some others. The selection of ecosystem services to be taken into account in plantation management depends both on local cultural values and on the particular environmental pressures considered to be most in need of mitigation.  相似文献   

5.
The watershed services provided by tropical natural and planted forests are critical to human well-being. An increasing number of valuation studies and experiences with payment for ecosystem services have dealt with the role of ecosystems in regulating the flow of water. However, several studies and experiences have been based on misconceptions about the role of forests and plantations in the hydrological cycle, despite the publication of many reviews by hydrologists. The objective of this paper is to evaluate whether meta-analyses applied to studies comparing water flows in tropical watersheds under natural or planted forests and non-forest lands can provide useful results for valuing watershed ecosystem services and making decisions. The meta-analyses show significantly lower total flows or base flows under planted forests than non-forest land uses. Meta-analyses conducted with subsamples of the data also show lower total flow and higher base flow under natural forests than non-forest land uses. However, the available studies were restricted to humid climates and particular forest types (Pinus and Eucalyptus planted forests and lowland natural forests). The small number of available studies with sufficient original data is a major constraint in the application of meta-analyses. This represents a major technical challenge for valuation studies or payment for ecosystem services, especially in countries where financial resources for implementing field research are scarce.  相似文献   

6.
Of the most common types of land use, agroecosystems put enormous pressure on many groups of biological organisms. Amphibians are not the exception and here we show the value of these habitats to the conservation of this group. We evaluated the diversity of amphibians in coffee plantations (traditional and specialized shade) and also in fragments of cloud forest, the ecosystem that was dominant in pre-agricultural central Veracruz, Mexico. A sampling effort of 2,688 person hours recorded 1,078 amphibians belonging to 26 species, 10 families and three orders. Based on the mean complementarity of 64 %, the non-metric multidimensional scaling analysis identified three groups of communities indicating a high degree of species turnover. The Craugastoridae family was dominant at the study sites, representing 40 % of the entire sample. Amphibian diversity was high in cloud forest fragments, followed by the traditional coffee plantation. However, amphibian richness in the specialized shaded coffee plantation was not significantly different from that of the other two habitats. We conclude that the different types of coffee agrosystems are reservoirs for at least 46 % of the species native to cloud forest, indicating that this habitat is very important to the conservation of the amphibian fauna in central Veracruz.  相似文献   

7.
热带海岛由于其独特的地理位置以及丰富的物种资源,使其旅游服务价值不同于一般的生态系统服务价值中的旅游服务价值。本文从生态系统服务价值评价指标体系中,提炼出与旅游者和旅游活动直接相关的,能被旅游者直接利用的生态系统服务作为热带海岛的旅游服务评价指标;同时根据热带海岛的特点,对以往的计算方法进行修正,得到热带海岛的旅游服务价值评价体系以及计算方法。本文区别于之前研究将旅游服务价值作为生态系统服务评价指标中的一部分,而是将其单独作为一类进行核算。参考前人的研究,本文将旅游服务价值评价指标体系分为林地、草地、耕地、湿地、滩涂、建设用地、水体7种用地类型和气体调节、气候调节、食物供给、环境净化、生物多样性、休闲娱乐、文化7种生态系统服务来进行计算。对热带海岛旅游服务价值进行评估,可以衡量生态系统为旅游发展所做出的贡献,也可以提高公众的生态意识,同时也为生态补偿提供理论依据。  相似文献   

8.
The major causes of deforestation and degradation of natural resources in the Belete-Gera Forest of Ethiopia are coffee production activities and encroachment into forestland to expand farmland and pasture. Population growth, and the government’s land-reform and re-settlement programs have caused local residents to lose harmony with the land. Forest management in this area hasn’t yet been fully developed. The objectives of this study are to identify the extent of deforestation and natural resource degradation, in preparation for a sound management plan. Encroachment of farmland and pasture into natural forest during the past four years has been identified through interviews and aerial photo interpretation. The encroachment rate is 1.45% per year. Encroachment occurred mostly on areas with gentle slopes adjacent to populated villages and along roads and footpaths. The extent and impact of coffee production activities were examined through agency documents, forest survey data and vegetation survey. It is estimated that up to 49% of the accessible natural forest is under the influence of coffee production activities, among which collecting of naturally grown coffee beans has the least and the coffee plantations has the most impact on the natural forest. Coffee plantations in natural forest have reduced the forest density and species diversity. Age structure of the trees is limited to mature and old classes only, which eventually endangers their function as shade for coffee plantations. This project was funded by the Japan International Cooperation Agency.  相似文献   

9.
鄱阳湖流域水土流失与森林生态环境控制管理对策   总被引:3,自引:0,他引:3  
江西省水土流失集中分布于鄱阳湖水系的"五河"及其支流流域,流域水土流失的主要来源分别是坡耕地、工业生产建设废弃物,尤其以林业用地水土流失最为严重。森林资源年龄结构比例失调,林地逆转流失严重,森林利用与恢复方式单一,致使水土流失控制所需要的森林生态防护功能供给不足。为了遏止水土流失,必须调整人工林单一树种结构,重建防护功能较高的复合型森林生态系统,同时调整和改革现行不合理的森林经营管理模式,变革坡耕地土地利用方式,实施全流域坡耕地退耕还林生态恢复工程。  相似文献   

10.
Forest ecosystems help conserve the quality of water resources in aquatic habitats. The conservation of biological diversity in aquatic and terrestrial ecosystems remains a communal concern. Aquatic ecosystems and resources are vulnerable but can be preserved and protected by forests. In sub-Saharan regions of Africa, water from ecosystems such as ponds still play important role in the livelihood of local populations. Water from temporary ponds is used by local populations for multiple needs; however, in this part of the world, the population is increasing, thus increasing human needs and activities and land use in the region. Land-use changes lead to deforestation, land degradation and the decline in freshwater, affecting human health and well-being. Forest degradation leads to the decline in ecosystem goods and services, particularly those related to watersheds. This study conducted in eastern Burkina Faso aimed to assess water quality of temporary ponds in protected forest areas (reserves) and surrounding villages. It was conducted in 61 temporary ponds where physical, chemical and biological variables were measured, such as water surface area, depth, transparency, macrophyte cover, pH, dissolved O2, conductivity, nutrient concentrations and algae biomass. The results showed that at p < 5%, water surface area (p = 0.02), depth (p = 0.00), nutrient content (p = 0.00), and algae biomass (p = 0.04) were significantly higher outside reserves than inside reserves. In contrast, macrophyte cover (mean cover percentages 53 vs. 44.5%) and water transparency (p = 0.02) were higher inside reserves. The variations in conductivity and pH were not significant. All trends showed the influences of human activities on water characteristics and the role forests and land cover had in preventing negative human impacts and disturbance of temporary ponds. Forests and land cover are important to water quality conservation and algae biomass regulation in temporary ponds. Protecting and managing forests is therefore an essential part of future strategies for limiting algal blooms and their negative consequences, maintaining water quality and providing clean water to citizens.  相似文献   

11.
In the last 20?years, the Mocotíes watershed in the Venezuelan Andes has experienced an intense process of land-use change, with natural forests being replaced by ??sun grown coffee?? (Coffea arabica) monocultures in sites of high slope, increasing risk conditions and the vulnerability of people living in lower parts of the watershed. Using a local-scale approach, 37 productive units (10% of total) in the San Isidro micro-watershed (51.85?km2) were assessed in order to evaluate local socioeconomic conditions and perceptions of ecosystem services, and how both are affected by human activity. Almost 65% of residents work in small farms of less than 5?ha, while family ownership remains the most important form of management. A significant lack of financial support was detected, support which is required to improve coffee productivity and improve conservation practices. Severe soil loss was detected in 45% of the area, associated with cultivation on steep slopes and the use of chemical fertilizers. Agroforestry and tree planting are well-regarded, as locals tend to recognize soil protection and climate change mitigation as two of the most important ecosystem services. Using a small-scale forestry approach, it is believed that current land management could be greatly improved to: (1) progressively introduce tree cover into coffee monocultures; (2) restore degraded areas where forest cover is lost and (3) reduce deforestation. Recommended policies and actions include institutional strengthening, decentralization and the development of community-based forest enterprises. The general principles presented in this work could provide a preliminary basis for basin-wide land restoration.  相似文献   

12.
以云南省文山州清水河水库为例,对其环境影响区域内土地利用变化进行分析,全面预测研究区生态系统服务价值和变化情况。结果表明:清水河水库实施后,研究区内土地利用类型并未发生显著变化,旱地依旧是主要的土地利用类型,生态系统总体格局并未发生改变;研究期间虽然生态系统服务总价值呈上升趋势,但工程建设对多数生态系统功能价值会有一定的负面影响,因此在生产建设和管理中,要加强林地保护,尽量降低生态系统的损失;清水河水库下闸蓄水后,水域生态系统服务价值的变化将会对研究区生态系统服务总价值将产生较大影响;研究区内生态系统服务之间存在显著的协同关系。  相似文献   

13.
Sacred groves are patches of forests preserved for their spiritual and religious significance.The practice gained relevance with the spread of agriculture that caused large-scale deforestation affecting biodiversity and watersheds.Sacred groves may lose their prominence nowadays,but are still relevant in Indian rural landscapes inhabited by traditional communities.The recent rise of interest in this tradition encouraged scientific study that despite its pan-Indian distribution,focused on India’s northeast,Western Ghats and east coast either for their global/regional importance or unique ecosystems.Most studies focused on flora,mainly angiosperms,and the faunal studies concentrated on vertebrates while lower life forms were grossly neglected.Studies on ecosystem functioning are few although observations are available.Most studies attributed watershed protection values to sacred groves but hardly highlighted hydrological process or water yield in comparison with other land use types.The grove studies require diversification from a stereotyped path and must move towards creating credible scientific foundations for conservation.Documentation should continue in unexplored areas but more work is needed on basic ecological functions and ecosystem dynamics to strengthen planning for scientifically sound sacred grove management.  相似文献   

14.
Forests are dynamic ecosystems, spatial mosaics of localized disturbances and regenerating vegetation. Following forest conversion to human land uses, expanding forest cover follows four different modes of reforestation: (a) spontaneous natural regeneration; (b) assisted natural regeneration; (c) agroforestry; and (d) commercial tree plantations. Natural regeneration fundamentally depends on the alignment of ecological and social factors at landscape scales. A deeper socioecological understanding of reforestation in the tropics will lead to the development of effective policies and governance structures that enhance forest cover and ecosystem services, protect biodiversity, and improve forest-dependent livelihoods.  相似文献   

15.
Greater understanding of the influences on long-term coffee productivity are needed to develop systems that are profitable, while maximizing ecosystem services and lowering negative environmental impacts. We examine a long-term experiment (15 years) established in Costa Rica in 2000 and compare intensive conventional (IC) coffee production under full sun with 19 agroforestry systems combining timber and service tree species with contrasting characteristics, with conventional and organic managements of different intensities. We assessed productivity through coffee yield and coffee morphological characteristics. IC had the highest productivity but had the highest yield bienniality; in the agroforestry systems productivity was similar for moderate conventional (MC) and intensive organic (IO) treatments (yield 5.3 vs. 5.0 t ha?1 year?1). Significantly lower yields were observed under shade than full sun, but coffee morphology was similar. Low input organic production (LO) declined to zero under the shade of the non-legume timber tree Terminalia amazonia but when legume tree species were chosen (Erythrina poepiggiana, Chloroleucon eurycyclum) LO coffee yield was not significantly different than for IO. For the first 6 years, coffee yield was higher under the shade of timber trees (Chloroleucon and Terminalia), while in the subsequent 7 years, Erythrina systems were more productive; presumably this is due to lower shade covers. If IC full sun plantations are not affordable or desired in the future, organic production is an interesting alternative with similar productivity to MC management and in LO systems incorporation of legume tree species is shown to be essential.  相似文献   

16.
We compared how management approaches affected shade tree diversity, soil properties, and provisioning and carbon sequestration ecosystem services in three shade coffee cooperatives. Collectively managed cooperatives utilized less diverse shade, and pruned coffee and shade trees more intensively, than individual farms. Soil properties showed significant differences among the cooperatives, with the following properties contributing to differentiation: N, pH, P, K, and Ca. Higher tree richness was associated with higher soil pH, CEC, Ca, and Mg, and lower K. Higher tree densities were associated with lower N, K, and organic matter. Although we found differences in the incidence of provisioning services (e.g., fruit), all plantations generated products other than coffee. No differences were observed between C-stocks. The history and institutional arrangements of cooperatives can influence management approaches, which affect ecosystem properties and services. Our study corroborates that interdisciplinary investigations are essential to understand the socio-ecological context of tropical shade coffee landscapes.  相似文献   

17.
Despite of being structurally simpler and species-impoverished than natural forests, agroforestry plantations can act as a secondary habitat for native species and sustain some biodiversity. In particular, insectivores can provide important ecosystem services such as insectivory, indirectly benefiting plants through the reduction of herbivory and increasing productivity, by diminishing herbivores abundance. The lending of these services could occur in agroforestry systems, and in the same magnitude that in natural environments, however it has not yet been assessed whether the direct effect of insectivores over insects and indirect effect on plants differ between natural and agroforestry environments depending on possible modulating factors such as climatic region, type of insectivore, trophic group of the preyed arthropod and length of insectivores experimental exclusion. In this study, through a meta-analysis, it was assessed the provision of ecosystem services by insectivores in agroforestry systems compared to natural systems, contrasting it with the modulating factors mentioned. In general, insectivorous species reduced arthropod abundance and plant herbivory, and increased plant productivity. The magnitude and direction of these effects did not differ between natural and agroforestry systems, and neither did between different climatic regions, type of insectivore, preyed arthropod trophic groups nor experiment length. The effect of insectivores on productivity can vary based on the variable used to measure productivity. Our results evidence the provision of services by the insectivores present in plantations, independently of factors that could modulate its magnitude and direction. In this way, enhancing the existence of these important interactions within plantations could represent a win–win scenario.  相似文献   

18.
湿地是一种非常重要的自然生态系统,湿地生态系统的服务功能多样、服务价值巨大,对湿地生态系统服务功能与价值的研究已经成为湿地科学研究中的一项重要内容。湿地生态系统在界面、景观、生物类群和生物地球化学循环等几个方面具有不同于其他生态系统的特征。在众多的生态功能中,湿地生态系统的维持生物多样性、固定CO2和调节区域气候、降解污染和净化水质、减缓径流和蓄洪防旱、水资源功能、产品资源、社会功能等7个方面的功能尤其突出。生态系统服务价值评价的方法主要有3种,即能值分析法、物质量评价法和价值量评价法,这3种评价方法各适合于开展的不同的生态系统评价。其中价值的货币化评价最为直观,也更容易被大众理解和接受,同时这种评价结果可以进行不同价值为33.3万亿美元,约等于全球GNP的1.8倍,其中湿地生态系统的年价值为4、9万亿关元,约占全部生态系统的14.7%。中国的学者陈仲新、张新时的研究结果,中国生态系统的年总价值7.8万亿元,其中陆地生态系统5.6万亿元,所计算的生态系统中湿地生态系统的年价值2.7万亿元,居各种生态系统价值的首位。根据逐项生态功能的评估,最后得到扎龙湿地的生态系统的年价值为156亿元人民币。目前湿地生态系统服务价值评价在评价方法和湿地生态过程两个方面需要更深入的研究。  相似文献   

19.
The complex interactions among endangered ecosystems, landowners’ interests, and different models of land tenure and use, constitute an important series of challenges for those seeking to maintain and restore biodiversity and augment the flow of ecosystem services. Over the past 10 years, we have developed a data-based approach to address these challenges and to achieve medium and large-scale ecological restoration of riparian areas on private lands in the state of São Paulo, southeastern Brazil. Given varying motivations for ecological restoration, the location of riparian areas within landholdings, environmental zoning of different riparian areas, and best-practice restoration methods were developed for each situation. A total of 32 ongoing projects, covering 527,982 ha, were evaluated in large sugarcane farms and small mixed farms, and six different restoration techniques have been developed to help upscale the effort. Small mixed farms had higher portions of land requiring protection as riparian areas (13.3%), and lower forest cover of riparian areas (18.3%), than large sugarcane farms (10.0% and 36.9%, respectively for riparian areas and forest cover values). In both types of farms, forest fragments required some degree of restoration. Historical anthropogenic degradation has compromised forest ecosystem structure and functioning, despite their high-diversity of native tree and shrub species. Notably, land use patterns in riparian areas differed markedly. Large sugarcane farms had higher portions of riparian areas occupied by highly mechanized agriculture, abandoned fields, and anthropogenic wet fields created by siltation in water courses. In contrast, in small mixed crop farms, low or non-mechanized agriculture and pasturelands were predominant. Despite these differences, plantations of native tree species covering the entire area was by far the main restoration method needed both by large sugarcane farms (76.0%) and small mixed farms (92.4%), in view of the low resilience of target sites, reduced forest cover, and high fragmentation, all of which limit the potential for autogenic restoration. We propose that plantations should be carried out with a high-diversity of native species in order to create biologically viable restored forests, and to assist long-term biodiversity persistence at the landscape scale. Finally, we propose strategies to integrate the political, socio-economic and methodological aspects needed to upscale restoration efforts in tropical forest regions throughout Latin America and elsewhere.  相似文献   

20.
Water temperature has profound effects on stream ecosystems. We studied effects of clear-fell logging Pinus radiata plantations on mid-summer water temperatures and recovery times in streams with 2–12 m wide channels. Post-logging increases were 2–3.8 °C for summer daily means and 4–7.3 °C for summer daily maxima. Rates of recovery of thermal regimes after logging were strongly negatively correlated with stream size, as indexed by catchment area, channel width or baseflow (r2 = 0.80–0.93). Summer daily mean and maximum temperatures declined during the riparian vegetation regrowth phase by 0.18 and 0.47 °C year−1, respectively, for the largest stream and 1.4 and 1.9 °C year−1 in the smallest stream. Thermal regimes were restored in small streams (2–4 m wide channels) about 6–8 years after clearfelling. In medium-sized streams (6–12 m wide channels), we predict this recovery will take 12–16 years.  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