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1.
Changing Farmers' Land Management Practices in the Hills of Nepal   总被引:2,自引:2,他引:0  
This paper sheds light on changing farmers' land management practices in two mountain watersheds, with and without external assistance, in the western hills of Nepal. Information used in the analysis were obtained through a survey of 300 households, group discussion, key informant interviews, and field observation conducted during April–September 1999. Confronted with ever-decreasing landholding size due to a steadily growing population and scarcity of nonfarming employment opportunities, farmers in both watersheds have increasingly adopted assorted types of structural and biological measures to control soil erosion, landslides, gully expansion, and soil nutrient loss to maintain or even enhance land productivity. Adoption of gully control measures, construction of the retention walls, alley cropping, use of vegetative measures for landslide control, mulching, and use of green manure and chemical fertilizers are found significantly high in the project area due to the provision of technical and financial support, whereas composting is found significantly high in the nonproject area. Different from the traditionally held beliefs, population pressure on a finite land resource has brought positive change in land management. However, the experience from both watersheds indicates that there is limit to the extent that resource poor farmers can respond to land degradation without any external assistance. Required is the arrangement for appropriate polices and support services and facilities enabling farmers to adopt locationally suitable and economically attractive land management technologies.  相似文献   

2.
Amid growing concern about the conservation of renewable natural resources, the process, extent and symptoms of their degradation are examined with specific reference to the Upper Pokhara Valley. Based on a household survey, field observations, informal deliberations and land use analysis, the results of this study reveal that forests and grazing land have been subject to increasing degradation caused by demographic, socioeconomic and institutional factors. The intensity of degradation varies by watershed. In particular, rainfed pakho land on steep slopes is under the severe threat of accelerating soil erosion, despite the construction of terraces. This calls for the formulation of a comprehensive natural resource conservation strategy which should be based on a framework comprising an integrated population control programme, planned land use changes and institutional reforms .  相似文献   

3.
Food security concerns and the scarcity of new productive land have put productivity enhancement of degraded lands back on the political agenda. In such a context, salt‐affected lands are a valuable resource that cannot be neglected nor easily abandoned even with their lower crop yields, especially in areas where significant investments have already been made in irrigation and drainage infrastructure. A review of previous studies shows a very limited number of highly variable estimates of the costs of salt‐induced land degradation combined with methodological and contextual differences. Simple extrapolation suggests that the global annual cost of salt‐induced land degradation in irrigated areas could be US$ 27.3 billion because of lost crop production. We present selected case studies that highlight the potential for economic and environmental benefits of taking action to remediate salt‐affected lands. The findings indicate that it can be cost‐effective to invest in sustainable land management in countries confronting salt‐induced land degradation. Such investments in effective remediation of salt‐affected lands should form part of a broader strategy for food security and be defined in national action plans. This broader strategy is required to ensure the identification and effective removal of barriers to the adoption of sustainable land management, such as perverse subsidies. Whereas reversing salt‐induced land degradation would require several years, interim salinity management strategies could provide a pathway for effective remediation and further showcase the importance of reversing land degradation and the rewards of investing in sustainable land management.  相似文献   

4.
Despite increased attention and demand for the adoption of agroforestry practices throughout the world, rigorous long-term scientific studies confirming environmental benefits from the use of agroforestry practices are limited. The objective was to examine nonpoint-source pollution (NPSP) reduction as influenced by agroforestry buffers in watersheds under grazing and row crop management. The grazing study consists of six watersheds in the Central Mississippi Valley wooded slopes and the row crop study site consists of three watersheds in a paired watershed design in Central Claypan areas. Runoff water samples were analyzed for sediment, total nitrogen (TN), and total phosphorus (TP) for the 2004 to 2008 period. Results indicate that agroforestry and grass buffers on grazed and row crop management sites significantly reduce runoff, sediment, TN, and TP losses to streams. Buffers in association with grazing and row crop management reduced runoff by 49 and 19%, respectively, during the study period as compared with respective control treatments. Average sediment loss for grazing and row crop management systems was 13.8 and 17.9 kg ha yr, respectively. On average, grass and agroforestry buffers reduced sediment, TN, and TP losses by 32, 42, and 46% compared with the control treatments. Buffers were more effective in the grazing management practice than row crop management practice. These differences could in part be attributed to the differences in soils, management, and landscape features. Results from this study strongly indicate that agroforestry and grass buffers can be designed to improve water quality while minimizing the amount of land taken out of production.  相似文献   

5.
Land degradation continues to be a major threat to local and national food security. With limited potential to develop new land, any increase in agricultural production must be sought largely through the better use of land already under cultivation. Concerns for the global environment associated with agriculture worldwide have also increased in recent years and require more coordinated efforts at global and national levels with decentralisation of activities at the local level.
This article presents an overview of land resources potential for food production, the processes and extent of land degradation and its economic and environmental costs and impacts, and highlights some macro-economic policies and institutional measures for the prevention of land degradation and rehabilitation of degraded lands. A people-centred programme is presented as a basis for decentralising activities for sustainable land use and land management. Finally, the need for better coordinated efforts of concerned UN, multinational agencies and NGOs for the implementation of Agenda 21 and related conventions is stressed.  相似文献   

6.
The relatively scarcity of flat or moderately sloping land in Central Appalachia make reclaimed surface mined lands attractive for agricultural uses. A reclaimed surface coal mine in southern West Virginia was placed under grazing management during the 1984 and 1985 growing seasons. Discharge was collected from summer-grazed watersheds of about 2.8 ha and 8.9 ha and analyzed, by the membrane-filtration method, for fecal coliforms (FC). Prior to grazing, in 1984, FC counts were < 20/100 ml. During the grazing season, FC ranged from <0/100 ml to> 1000/100 ml in 1984 and from 0/100 ml to > 2500/100 ml in 1985. FC counts remained high during warm periods for several months after grazing ceased. It was concluded that the bacteriological quality of receiving streams was impacted by grazing the reclaimed area and recommended standards for point sources were often exceeded; however, the FC counts did not appear to be any greater than what would have been expected from grazed, undisturbed areas. Reclaimed surface mine areas in Appalachia have the potential to be a valuable “flat land” resource and grazing appears to be an alternative post mine land use that affects bacteriological water quality in a similar manner as “natural” pastures. However, good management practices may be necessary to avoid bacterial contamination of adjacent bodies of water.  相似文献   

7.
Temperate grazing lands in Garhwal Himalaya are rich in herbaceous vegetation and extensively used for grazing by locally owned livestock. Capillipedium parviflorum is a frequently occurring and dominant grass species under Pine canopy in associate with several herbs. Beside, grazing and extensive fire, interactions among associated species is a determining factor of community structure. In this article the dominant diversity pattern of vegetation in temperate grazing land along two different altitudes and having different slope aspects is described. Interaction between dominant and co-dominant species with their niche appearance and niche overlap measurement was also observed and presented here. South and west facing slopes had maximum species and diversity values while east north facing slopes had higher species dominant. Capillipedium parviflorum and other grasses had maximum niche values and were dominant and co dominant species. Three types of interspecific interaction were observed between species and grasses were observed as succeeding species in all sites of different topographic conditions. Dominant diversity pattern along with resource partitioning and interspecific competition is discussed and presented here.  相似文献   

8.
Depletion of vegetation by overgrazing in arid environments has long-lasting effects on the environmental quality over extended geographic areas. An adequate inspection of habitat changes requires scaled up procedures that would allow assessing end-points of environmental status in broad areas that would be based on processes occurring at the plant canopy level. Our purpose was to find indicators of land degradation–conservation status for use in land monitoring programs and in planning management practices that would be amenable to further up-scaling for use with remotely sensed imagery. In several sites of the Patagonian Monte differing in the impact of grazing management, we evaluated vegetation attributes at three spatial scales. At the population scale, we found that the severity of grazing impact was characterized by the reduction of the palatable grass, P. ligularis, outside and inside shrub canopies. At the vegetation patch scale, we found that land degradation by domestic herbivore impact was characterized by changes in attributes of patch shape (radius, height, internal canopy cover) and patch abundance. At the plant community scale, we found that the structure of the plant canopy as described using Fourier analysis of cover data changed after long-term grazing impact consistently with the modifications in plant population and patch structures. We present a conceptual multiscale scenario of structural changes triggered by domestic herbivore impact, and quantitative indicators of plant structure and processes useful to develop management strategies of the Patagonian-Monte that would conserve its natural habitats. The developed end-points are also amenable for use in land conservation assessment through remotely sensed imagery.  相似文献   

9.
In this contemporary interpretation of the widespread land degradation problem in Southeast Asia, it is hypothesized that spatial interplay of environmental and socioeconomic predictors determines the occurrence of land degradation. Village surveys, remote sensing and spatial auto‐logistic modelling of the relationship between degradation and land use dynamics in Lam Phra Phloeng watershed of Thailand enabled 80.2% of land to be classified correctly in terms of the presence or absence of erosion and explained 53.2% of the total variation. Cultivation and dependence on agriculture for livelihood positively and significantly affect degradation. Lack of access to institutional credit and land titles significantly increased the probability of occurrence of degradation. On the other hand, education and social cohesion are negatively associated with the occurrence of degradation. The Relative Operating Characteristic (ROC) curve was used to measures the performance of the model. The calculated area under the curve (0.879) suggests that significant predictor variables in the model can be confidently used to forecast the likelihood of occurrence of degradation and thus to identify priority areas for intervention. Policies to reduce land degradation should include measures to reduce pressure on the land, including alternative income sources. Policies could mobilize capital to invest in encouraging nature‐based tourism and other off‐farm income options.  相似文献   

10.
Healthy watersheds provide valuable services to society, including the supply and purification of fresh water. Because these natural ecosystem services lie outside the traditional domain of commercial markets, they are undervalued and underprotected. With population and development pressures leading to the rapid modification of watershed lands, valuable hydrological services are being lost, which poses risks to the quality and cost of drinking water and the reliability of water supplies. Increasing the scale and scope of programmes to protect hydrological services requires policies that harmonize land uses in watersheds with the provision of these important natural services. This article summarizes key attributes of hydrological services and their economic benefits; presents a spectrum of institutional mechanisms for safeguarding those services; discusses programmes in Quito (Ecuador), Costa Rica and New York City; and offers some lessons learned and recommendations for achieving higher levels of watershed protection.  相似文献   

11.
The adoption of democracy and the market economy ideology in post-communist Central and Eastern Europe is encouraging changes in rural public land policy. A system of state public land is being partly dismantled, to be replaced by private ownership.This paper exploresthe present dynamics of the rural public land reprivatization process in Slovakia. In Slovakia approximately 40% of rural public land are being reprivatized. Evidence indicates that the reprivatization of public land is having a detrimental effect on the management of State Forests, National Parks and game management.The integrated, centrally planned public land system of the communist era is being fragmented by reprivatization. This paper argues that this process is creating barriers to the achievement of the sustainable management of the natural resources of rural Slovakia. Recent Governmentof Slovakia laws and policies on sustainable development and environmental management, and adherence to international environmental conventions may provide opportunities for enlightened change in the reprivatization process. A public land system in a democratic free market economy can be an effective mechanism to secure the protection and the sustainable managementof forests, farmland, game, outstanding landscapes and wildlife. This is an opportune time to debate the future of rural public land in Central and Eastern Europe in order that enlightened policy making may be fostered.  相似文献   

12.
This study assessed changes in forest cover in a mountain watershed in central Nepal between 1976 and 2000 by comparing classified satellite images coupled by GIS analyses, and examined the association of forest change with major physiographic, economic, and local forest governance parameters. The results showed an increase in forested area (forest plus shrublands) by 7.6% during 1976–2000. Forest dynamism (changes including improvement, deterioration, gain, and loss) was highest in low-elevation, south-facing and less-steep slopes that were closer to roads. Proportionately the highest net improvement and gain to forested area also took place in those locations. Forest degradation occurred at twice the rate of improvement in high elevation areas (> 2300 m). Forests located in urban and semiurban areas (i.e., a market-oriented economy) experienced a proportionately higher amount of net improvement and gain than forests in rural areas (i.e., a subsistence economy). Among the three governance arrangements, proportionately the highest net improvement and gain took place in semigovernment forests (forested area legally under the forest department but with de facto control and claim of ownership by local communities and/or municipality) followed by formalized community forests (including leasehold). Government forests, which were mostly found in the southern high mountains and had virtually open access, remained relatively stable during the study period. Over 50% of the watershed forests have not come under community-based management despite favorable policy and more than two decades of government intervention with continuous donor support. The findings indicate that the present one size fits all approach of community forest handover policy in Nepal needs rethinking to accommodate biophysical and socioeconomic variations across the country.  相似文献   

13.
Federal land managers are faced with the task of balancing multiple uses and goals when making decisions about land use and the activities that occur on public lands. Though climate change is now well recognized by federal agencies and their local land and resource managers, it is not yet clear how issues related to climate change will be incorporated into on-the-ground decision making within the framework of multiple use objectives. We conducted a case study of a federal land management agency field office, the San Juan Public Lands Center in Durango, CO, U.S.A., to understand from their perspective how decisions are currently made, and how climate change and carbon management are being factored into decision making. We evaluated three major management sectors in which climate change or carbon management may intersect other use goals: forests, biofuels, and grazing. While land managers are aware of climate change and eager to understand more about how it might affect land resources, the incorporation of climate change considerations into everyday decision making is currently quite limited. Climate change is therefore on the radar screen, but remains a lower priority than other issues. To assist the office in making decisions that are based on sound scientific information, further research is needed into how management activities influence carbon storage and resilience of the landscape under climate change.  相似文献   

14.
The Southeastern United States is a global center of freshwater biotic diversity, but much of the regions aquatic biodiversity is at risk from stream degradation. Nonpoint pollution sources are responsible for 70% of that degradation, and controlling nonpoint pollution from agriculture, urbanization, and silviculture is considered critical to maintaining water quality and aquatic biodiversity in the Southeast. We used an ecological risk assessment framework to develop vulnerability models that can help policymakers and natural resource managers understand the impact of land cover changes on water quality in North Carolina. Additionally, we determined which landscape characteristics are most closely associated with macroinvertebrate community tolerance of stream degradation, and therefore with lower-quality water. The results will allow managers and policymakers to weigh the risks of management and policy decisions to a given watershed or set of watersheds, including whether streamside buffer protection zones are ecologically effective in achieving water quality standards. Regression analyses revealed that landscape variables explained up to 56.3% of the variability in benthic macroinvertebrate index scores. The resulting vulnerability models indicate that North Carolina watersheds with less forest cover are at most risk for degraded water quality and steam habitat conditions. The importance of forest cover, at both the watershed and riparian zone scale, in predicting macrobenthic invertebrate community assemblage varies by geographic region of the state.  相似文献   

15.
Summary The impacts of human activities on the bio-geophysical and socio-economic environment of the Himalayas are analysed. The main man-induced activities which have accelerated ecological degradation and threatened the equilibrium of Himalayan mountain ecosystems are stated as: unplanned land use, cultivation on steep slopes, overgrazing, major engineering activities, over-exploitation of village or community forests, lopping of broad leaved plant species, shifting cultivation (short cycle) in north-east India, tourism and recreation. Monoculture in forests, erosion and landslides have resulted in one–third of the total Himalayan land area becoming environmentally derelict. Cold desert conditions prevail in 41,500 km2 of north-west Himalayas and are encouraged by traditional pasturalism. The geo-morphological conditions are major factors responsible for landslides which cause major havoc every year in the area. Other physical problems exist, such as eutrophication, drying up of the natural springs, the recession of the glaciers and changes in surface and ground water hydrology. Wild fauna, like musk deer (Moschus mischiferus) and the snow leopard (Panthera uncia), are now under threat partially due to changes in their habitat and the introduction of exotic plant species. Population pressure and migration are major factors responsible for poverty in the hills. The emigration of the working male population has resulted in the involvement of women as a major work-force. This work includes trekking for hours to collect fodder, timber and drinking water in addition to household duties. Guidelines, with special emphasis on the application of environmental impact assessments for the management of the Himalayas, are proposed.Drs Ahmad and Rawat are scientists, and Dr Rai is a research associate, at the Government of India, Ministry of Environment and Forests, G.B. Pant Institute of Himalayan Environment and Development. Correspondence should be addressed to Dr Afroz Ahmad.  相似文献   

16.
The primary role of remote sensing in land management and planning has been to provide information concerning the physical characteristics of the land which influence the management of individual land parcels or the allocation of lands to various uses These physical characteristics have typically been assessed through aerial photography, which is used to develop resource maps and to monitor changing environmental conditions These uses are well developed and currently well integrated into the planning infrastructure at local, state, and federal levels in the United States.Many newly emerging uses of remote sensing involve digital images which are collected, stored, and processed automatically by electromechanical scanning devices and electronic computers Some scanning devices operate from aircraft or spacecraft to scan ground scenes directly; others scan conventional aerial transparencies to yield digital images. Digital imagery offers the potential for computer-based automated map production, a process that can significantly increase the amount and timeliness of information available to land managers and planners.Future uses of remote sensing in land planning and management will involve geographic information systems, which store resource information in a geocoded format. Geographic information systems allow the automated integration of disparate types of resource data through various types of spatial models so that with accompanying sample ground data, information in the form of thematic maps and/ or aerially aggregated statistics can be produced Key issues confronting the development and integration of geographic information systems into planning pathways are restoration and rectification of digital images, automated techniques for combining both quantitative and qualitative types of data in information-extracting procedures, and the compatibility of alternative data storage modes  相似文献   

17.
Evaluation of compost blankets for erosion control from disturbed lands   总被引:1,自引:0,他引:1  
Soil erosion due to water and wind results in the loss of valuable top soil and causes land degradation and environmental quality problems. Site specific best management practices (BMP) are needed to curb erosion and sediment control and in turn, increase productivity of lands and sustain environmental quality. The aim of this study was to investigate the effectiveness of three different types of biodegradable erosion control blankets- fine compost, mulch, and 50-50 mixture of compost and mulch, for soil erosion control under field and laboratory-scale experiments. Quantitative analysis was conducted by comparing the sediment load in the runoff collected from sloped and tilled plots in the field and in the laboratory with the erosion control blankets. The field plots had an average slope of 3.5% and experiments were conducted under natural rainfall conditions, while the laboratory experiments were conducted at 4, 8 and 16% slopes under simulated rainfall conditions. Results obtained from the field experiments indicated that the 50-50 mixture of compost and mulch provides the best erosion control measures as compared to using either the compost or the mulch blanket alone. Laboratory results under simulated rains indicated that both mulch cover and the 50-50 mixture of mulch and compost cover provided better erosion control measures compared to using the compost alone. Although these results indicate that the 50-50 mixtures and the mulch in laboratory experiments are the best measures among the three erosion control blankets, all three types of blankets provide very effective erosion control measures from bare-soil surface. Results of this study can be used in controlling erosion and sediment from disturbed lands with compost mulch application. Testing different mixture ratios and types of mulch and composts, and their efficiencies in retaining various soil nutrients may provide more quantitative data for developing erosion control plans.  相似文献   

18.
Forests and competing land uses in Kenya   总被引:1,自引:0,他引:1  
Indigenous forests in Kenya, as in other developing countries, are under heavy pressure from competing agricultural land uses and from unsustainable cutting. The problem in Kenya is compounded by high population growth rates and an agriculturally based economy, which, even with efforts to control birth rates and industrialize, will persist into the next century. Both ecological and economic consequences of these pressures need to be considered in land-use decision making for land and forest management to be effective. This paper presents one way to combine ecological and economic considerations. The status of principal forest areas in Kenya is summarized and competing land uses compared on the basis of ecological functions and economic analysis. Replacement uses do not match the ecological functions of forest, although established stands of tree crops (forest plantations, fuel wood, tea) can have roughly comparable effects on soil and water resources. Indigenous forests have high, although difficult to estimate, economic benefits from tourism and protection of downstream agricultural productivity. Economic returns from competing land uses range widely, with tea having the highest and fuel wood plantations having returns comparable to some annual crops and dairying. Consideration of ecological and economic factors together suggests some trade-offs for improving land allocation decisions and several management opportunities for increasing benefits or reducing costs from particular land uses. The evaluation also suggests a general strategy for forest land management in Kenya.The views and interpretations expressed in this article are those of the authors and should not be attributed to the World Bank, its affiliated organizations, or any individual acting on their behalf.  相似文献   

19.
The official environmental discourse in Laos describes a “chain of degradation” stretching from upland shifting cultivation, increased runoff and soil erosion to the siltation of wetlands and reservoirs. This perspective has had wide‐ranging impacts on rural development policy which, in the uplands, has long favoured forest conservation over agriculture. Integrating soil erosion and water sediment data with local perceptions of land degradation in an upland village of northern Laos, this study tests the validity of the official environmental discourse. Biophysical measurements made in a small agricultural catchment indicate a significant correlation between the spatial extent of cultivation and soil erosion rates. However, sediment yields recorded at the outlet of the catchment highlight relatively low levels of off‐site sediment exportation. Furthermore, farmers' perceptions suggest that local land degradation issues and crop yield declines could be less related to soil erosion than to agricultural land shortage, increased weed competition, and fertility losses resulting from the intensification of shifting cultivation. The study concludes that a better understanding and management of land degradation issues can be achieved by developing more inclusive and scientifically‐informed approaches to environmental perceptions and narratives.  相似文献   

20.
As human influences fragment native communities and ecosystems, remaining land must be better managed to conserve many elements of biodiversity. Much of this land is privately held, yet traditional private land-use management practices often further diminish biodiversity by promoting favored or edge-adapted species. Today, private land stewards are increasingly aware of and concerned about biodiversity, but little guidance exists for them to make land-use decisions incorporating principles and knowledge from conservation biology. Consequently, most management strategies are highly subjective. This article addresses that problem by introducing current conservation wisdom to management and use of private lands. The result is a model program for developing land management plans, with the goal of maintaining viable populations and natural distributions of native species and communities from a landscape perspective. The program establishes a protocol for classifying sites according to the importance of their species, communities, and other elements to global and regional biodiversity. These site classifications are based on the management objectives necessary to maintain important elements. Once managers classify a site, the program provides management standards, general stewardship principles, examples of land management strategies, and basic monitoring and evaluation procedures.  相似文献   

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