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1.
Alleviating human–carnivore conflict is central to large carnivore conservation and is often of economic importance, where people coexist with carnivores. In this article, we report on the patterns of predation and economic losses from wild carnivores preying on livestock in three villages of northern Baima Xueshan Nature Reserve, northwest Yunnan during a 2-year period between January 2010 and December 2011. We analyzed claims from 149 households that 258 head of livestock were predated. Wolves (Canis lupus) were responsible for 79.1 % of livestock predation; Asiatic black bears (Selenarctos thibetanus) and dholes (Cuon alpinus) were the other predators responsible. Predation frequency varied between livestock species. The majority of livestock killed were yak–cattle hybrids or dzo (40.3 %). Wolves killed fewer cattle than expected, and more donkeys and horses than expected. Wolves and bears killed more adult female and fewer adult male livestock than expected. Intensified predation in wet season coincided with livestock being left to graze unattended in alpine meadows far away from villages. On average, carnivore attacks claimed 2.1 % of range stock annually. This predation represented an economic loss of 17 % (SD = 14 %) of the annual household income. Despite this loss and a perceived increase in carnivore conflict, a majority of the herders (66 %) still supported the reserve. This support is primarily due to the benefits from the collection of nontimber resources such as mushrooms and medicinal plants. Our study also suggested that improvement of husbandry techniques and facilities will reduce conflicts and contribute to improved conservation of these threatened predators.  相似文献   

2.
The success of conserving biological resources in any Biosphere Reserve or protected area depends on the extent of support and positive attitudes and perceptions of local people have towards such establishments. Ignoring the dependence of the local people for their subsistence needs on resources of such areas leads to conflicts between protected area managers and the local inhabitants. Crop yield losses and livestock depredation were serious problems observed in most buffer zone villages of Nanda Devi Biosphere Reserve. In the present study 10 villages situated in the buffer zone of Nanada Devi Biosphere Reserve (1612 km2 area) in Chamoli district of Uttaranchal, India were studied during 1996-97 using a questionnaire survey of each household (419 = households; 2253 = total population in 1991; 273 ha = cultivated area). Estimates of crop yield losses were made using paired plots technique in four representative villages for each crop species. The magnitude of crop yield losses varied significantly with the distance of agricultural field from forest boundary. The total crop yield losses were high for wheat and potato in all the villages. The spatial distribution of total crop yield losses in any village indicated that they were highest in the area near to forest and least in the area near to village for all crops. Losses from areas near to forest contributed to more than 50% of total losses for each crop in all villages. However, in Lata, Peng and Tolma villages, the losses are high for kidney bean and chemmi (local variety of kidney bean) which varied between 18.5% to 30% of total losses in those villages. Potato alone represents 43.6% of total crop yield loss due to wildlife in Dronagiri village in monetary terms. Among the crops, the monetary value of yield losses are least for amaranth and highest for kidney bean. The projected total value of crop yield losses due to wildlife damage for buffer zone villages located in Garhwal Himalaya is about Rs. 538,620 (US$ 15,389). Besides food grains, horticultural crops i.e. apple, also suffered maximum damage. Major wildlife agents responsible for crop damage were wild boar, bear, porcupine, monkey, musk deer and partridge (chokor). Monkey and wild boar alone accounted for about 50% to 60% of total crop damage in the study villages. Goat and sheep are the major livestock killed by leopard. The total value of livestock losses at prevailing market rates is about Rs. 1,024,520 (US$ 29,272) in the study villages. Due to existing conservation policies and laxity in implementation of preventive measures, the problems for local inhabitants are increasing. Potential solutions discussed emphasize the need to undertake suitable and appropriate protective measures to minimize the crop losses. Change in cropping and crop composition, particularly cultivation of medicinal plants (high value low volume crops), were also suggested. Besides, fair and quick disbursement of compensation for crop loss and livestock killing need to be adopted. Local people of the buffer zone area already have a negative attitude towards park/reserve establishment due to socio-political changes inducing major economic losses and this attitude may lead to clashes and confrontations if proper ameliorative measures are not taken immediately.  相似文献   

3.
Economic analysis is a useful tool to aid decisions on what to do about wildlife impacts, such as those of vertebrate predators on livestock farmers. The case-study of lamb predation by foxes in Britain is used to develop a theoretical economic model, with the aim of determining a financially optimal solution to minimise the total costs of livestock predation at the farm-level. Total costs include output losses and expenditure on preventive and control measures, in this case indoor housing and lethal fox control. The model is tested empirically with data from a questionnaire survey of sheep farmers and field data on fox population densities in Britain. Regression analyses are used to determine the relationships between lamb losses and expenditure on indoor housing, fox population density and other non-management characteristics. The effect of fox abundance on the cost of fox control is also assessed. Marginal analysis is used to determine the total cost-minimising solution from the farmer's point-of-view, in terms of how many ewes should be housed indoors and for how long, as well as how many foxes should be killed in addition to any lethal control already carried out. Optimal solutions vary according to farm characteristics, including flock size and the regional location of farms. In all cases, to minimise the costs of predation, as many ewes as possible should be housed. However, it is not worthwhile housing them for more than a day after lambing. Efficient fox predation management does not necessarily mean that lamb losses should be reduced to zero, and additional fox control is not worthwhile on the majority of farms. The analysis provides a framework for future evaluations of wildlife impacts and cost-effective management of these problems.  相似文献   

4.
Conflict with humans over livestock and crops seriously undermines the conservation prospects of India's large and potentially dangerous mammals such as the tiger (Panthera tigris) and elephant (Elephas maximus). This study, carried out in Bhadra Tiger Reserve in south India, estimates the extent of material and monetary loss incurred by resident villagers between 1996 and 1999 in conflicts with large felines and elephants, describes the spatiotemporal patterns of animal damage, and evaluates the success of compensation schemes that have formed the mainstay of loss-alleviation measures. Annually each household lost an estimated 12% (0.9 head) of their total holding to large felines, and approximately 11% of their annual grain production (0.82 tonnes per family) to elephants. Compensations awarded offset only 5% of the livestock loss and 14% of crop losses and were accompanied by protracted delays in the processing of claims. Although the compensation scheme has largely failed to achieve its objective of alleviating loss, its implementation requires urgent improvement if reprisal against large wild mammals is to be minimized. Furthermore, innovative schemes of livestock and crop insurance need to be tested as alternatives to compensations.  相似文献   

5.
Public lands occupied by feral horses in North America are frequently managed for multiple uses with land use conflict occurring among feral horses, livestock, wildlife, and native grassland conservation. The factors affecting habitat use by horses is critical to understand where conflict may be greatest. We related horse presence and abundance to landscape attributes in a GIS to examine habitat preferences using 98 field plots sampled within a portion of the Rocky Mountain Forest Reserve of SW Alberta, Canada. Horse abundance was greatest in grassland and cut block habitats, and lowest in conifer and mixedwood forest. Resource selection probability functions and count models of faecal abundance indicated that horses preferred areas closer to water, with reduced topographic ruggedness, situated farther from forests, and located farther away from primary roads and trails frequented by recreationalists, but closer to small linear features (i.e. cut lines) that may be used as beneficial travel corridors. Horse presence and abundance were closely related to cattle presence during summer, suggesting that both herbivores utilise the same habitats. Estimates of forage biomass removal (44 %) by mid-July were near maximum acceptable levels. In contrast to horse-cattle associations, horses were negatively associated with wild ungulate abundance, although the mechanism behind this remains unclear and warrants further investigation. Our results indicate that feral horses in SW Alberta exhibit complex habitat selection patterns during spring and summer, including overlap in use with livestock. This finding highlights the need to assess and manage herbivore populations consistent with rangeland carrying capacity and the maintenance of range health.  相似文献   

6.
The aim of this study was to assess the potential for coexistence between rural people (living adjacent to a protected area) and predators (from the same area) ranging onto communal land. Ninety members of local communities bordering Manyeleti Game Reserve, which is contiguous with Kruger National Park, South Africa were interviewed. Respondents expressed diverging attitudes toward predators, which were more favorable among participants with higher education. Negative views were particularly due to fear of human and livestock losses, especially to lions, Panthera leo. Lions were thought to be the most abundant predator both within and outside the reserve. Lions were also the best known predator and were most often held responsible for killing livestock. Despite these livestock losses and a lack of conservation education, most participants voiced favorable opinions about large carnivore conservation, as predators were considered an integral part of the respondents’ natural heritage. Thanks to this cultural tolerance and also because of a largely accepted management policy regarding predator control, large carnivores and people can coexist in the vicinity of Kruger National Park.  相似文献   

7.
Crop and livestock losses to wildlife are a concern for people neighboring many protected areas (PAs) and can generate opposition to conservation. Examining patterns of conflict and associated tolerance is important to devise policies to reduce conflict impacts on people and wildlife. We surveyed 398 households from 178 villages within 10 km of Ranthambore, Kanha, and Nagarahole parks in India. We compared different attitudes toward wildlife, and presented hypothetical response scenarios, including killing the problem animal(s). Eighty percent of households reported crop losses to wildlife and 13 % livestock losses. Higher crop loss was associated with more cropping months per year, greater crop variety, and more harvest seasons per year but did not vary with proximity to the PA, suggesting that PAs are not necessarily “sources” for crop raiders. By contrast, complaints of “depredating carnivores” were associated with people-grazing animals and collecting resources from PAs. Many households (83 %) engaged in mitigation efforts. We found that only fencing and guard animals reduce crop losses, and no efforts to lower livestock losses. Contrary to our expectations, carnivores were not viewed with more hostility than crop-raiding wildlife. Households reported greater inclination to kill herbivores destroying crops or carnivores harming people, but not carnivores preying on livestock. Our model estimated crop loss was 82 % across surveyed households (highest in Kanha), while the livestock loss experienced was 27 % (highest in Ranthambore). Our comparative study provides insights into factors associated with conflict loss and tolerance, and aids in improving ongoing conservation and compensation efforts.  相似文献   

8.
Hunsaker, Carolyn T., Thomas W. Whitaker, and Roger C. Bales, 2012. Snowmelt Runoff and Water Yield Along Elevation and Temperature Gradients in California’s Southern Sierra Nevada. Journal of the American Water Resources Association (JAWRA) 48(4): 667‐678. DOI: 10.1111/j.1752‐1688.2012.00641.x Abstract: Differences in hydrologic response across the rain‐snow transition in the southern Sierra Nevada were studied in eight headwater catchments – the Kings River Experimental Watersheds – using continuous precipitation, snowpack, and streamflow measurements. The annual runoff ratio (discharge divided by precipitation) increased about 0.1 per 300 m of mean catchment elevation over the range 1,800‐2,400 m. Higher‐elevation catchments have lower vegetation density, shallow soils with rapid permeability, and a shorter growing season when compared with those at lower elevations. Average annual temperatures ranged from 6.8°C at 2,400 m to 8.6 at 1,950 m elevation, with annual precipitation being 75‐95% snow at the highest elevations vs. 20‐50% at the lowest. Peak discharge lagged peak snow accumulation on the order of 60 days at the higher elevations and 20 to 30 days at the lower elevations. Snowmelt dominated the daily streamflow cycle over a period of about 30 days in higher elevation catchments, followed by a 15‐day transition to evapotranspiration dominating the daily streamflow cycle. Discharge from lower elevation catchments was rainfall dominated in spring, with the transition to evapotranspiration dominance being less distinct. Climate warming that results in a longer growing season and a shift from snow to rain would result in earlier runoff and a lower runoff ratio.  相似文献   

9.
In India, millions of tones of livestock excreta are produced. Our study explores the potential of an epigeic earthworm Eisenia foetida to compost different livestock excreta (cow, buffalo, horse, donkey, sheep, goat and camel) into value added product (vermicompost) at the laboratory scale. Vermicomposting resulted in lowering of pH, electrical conductivity, potassium and C:N ratio and increase in nitrogen and phosphorus contents. Total K was lower in the final cast than in the initial feed. C:N ratios of the vermicomposts ranged from 16.2 ± 2.17 to 75.4 ± 6.84. Microbial activity measured as dehydrogenase activity in buffalo, donkey and camel wastes increased with time up to day 90. But in sheep and goat wastes, maximum dehydrogenase activity was recorded on day 60 and decreased thereafter. The cocoons and hatchlings production by Eisenia foetida in different excreta were also investigated. The greatest number and biomass of hatchlings was recorded in horse excreta followed by cow, goat and sheep excreta. Thus, cow, horse, sheep and goat excreta show potential as good substrates in vermicomposting using Eisenia foetida, although further research is required to explore the feasibility of use of buffalo, donkey and camel excreta in combination with cow/sheep/goat excreta.  相似文献   

10.
Trends in climatic variables, streamflow, agricultural practices, and loads of nutrients and suspended solids were estimated for 1976-1995 in the Maumee and Sandusky watersheds, two large agricultural basins draining to Lake Erie. To understand the contributions that various factors may have made to the trends in loads, earlier results of models linking loads to explanatory variables were combined with estimated trends in those variables. The study period was characterized by increases in temperature, wintertime precipitation and streamflow, conservation farming, and loads of nitrate and total suspended solids; decreases in snowfall and snow cover, fertilizer, manure from livestock, and loads of soluble reactive phosphorus; and relatively steady exports of total phosphorus. After removing the effects of trends in streamflow, nitrate loads increased much less while total suspended solids and total phosphorus loads declined. The analysis suggests that the nitrate increases were due largely to climatic factors, particularly increases in winter streamflow, decreases in snowfall and snow cover, and declining annual precipitation. Decreases in soluble reactive phosphorus were associated with changes in agricultural practices, particularly declines in fertilizer deliveries and head of livestock.  相似文献   

11.
The management of large carnivores in multiuse landscapes is always controversial, and managers need to balance a wide range of competing interests. Hunter harvest is often used to limit population size and distribution but is proving to be both controversialand technically challenging. Eurasian lynx (Lynx lynx) are currently managed as a game species in Norway. We describe an adaptive management approach where quota setting is based on an annual census and chart the population development through the period 1996–2008, as management has become significantly more sophisticated and better informed by the increased availability of scientific data. During this period the population has been through a period of high quotas and population decline caused by fragmented management authority and overoptimistic estimates of lynx reproduction, followed by a period of recovery due to quota reductions. The modern management regime is placed in the context of shifting policy during the last 160 years, during which management goals have moved from extermination stimulated by bounties, through a short phase of protection, and now to quota-regulated harvest. Much management authority has also been delegated from central to local levels. We conclude that adaptive management has the potential to keep the population within some bounded limits, although there will inevitably be fluctuation.  相似文献   

12.
Clilverd, Hannah M., Daniel M. White, Amy C. Tidwell, and Michael A. Rawlins, 2011. The Sensitivity of Northern Groundwater Recharge to Climate Change: A Case Study in Northwest Alaska. Journal of the American Water Resources Association (JAWRA) 47(6):1228–1240. DOI: 10.1111/j.1752‐1688.2011.00569.x Abstract: The potential impacts of climate change on northern groundwater supplies were examined at a fractured‐marble mountain aquifer near Nome, Alaska. Well water surface elevations (WSE) were monitored from 2004‐2009 and analyzed with local meteorological data. Future aquifer response was simulated with the Pan‐Arctic Water Balance Model (PWBM) using forcings (air temperature and precipitation) derived from fifth‐generation European Centre Hamburg Model (ECHAM5) global circulation model climate scenarios for extreme and modest increases in greenhouse gases. We observed changes in WSE due to the onset of spring snowmelt, low intensity and high intensity rainfall events, and aquifer head recession during the winter freeze period. Observed WSE and snow depth compared well with PWBM‐simulated groundwater recharge and snow storage. Using ECHAM5‐simulated increases in mean annual temperature of 4‐8°C by 2099, the PWBM predicted that by 2099 later freeze‐up and earlier snowmelt will decrease seasonal snow cover by one to two months. Annual evapotranspiration and precipitation are predicted to increase 27‐40% (55‐81 mm) and 33‐42% (81‐102 mm), respectively, with the proportion of snowfall in annual precipitation decreasing on average 9‐25% (p < 0.05). The amount of snowmelt is not predicted to change significantly by 2099; however, a decreasing trend is evident from 2060 in the extreme ECHAM5 greenhouse gas scenario. Increases in effective precipitation were predicted to be great enough to sustain sufficient groundwater recharge.  相似文献   

13.
This paper analyzes five major causes of park-people conflicts that have occurred in Nepal's Royal Chitwan National Park. The causes include illegal transactions of forest products from the park, livestock grazing in the park, illegal hunting and fishing, crop damage, and threats to human and animal life caused by wild animals from the park. The conflicts indicate a reciprocal relationship between the park and local people. They reflect the attitudes of local people and representatives of the park authority whose priorities and objectives largely diverge. The results show that people settled adjacent to the park are heavily dependent on its resources. Even in places where some, albeit few alternative sources exist, local people continue to trespass the park boundary as these sources are inadequate to ensure the fulfillment of local people's resource needs. Illegal transactions of resources continue throughout the year; however, they are less intense during summer due to flooding caused by the Rapti River, which forms the park boundary towards the northern section where this study is conducted. The frequency of local people's visits to the park is mainly determined by their age, distance between homesteads and park, and volume of crop loss caused by wild animals. Crop damage is the function of size of landholding, distance, and frequency of crop raid. Local people claim that they have no intention of letting their livestock graze in the park; however, the dense vegetation of the park attracts livestock grazing on riverbanks just outside the open park boundary. Many head of livestock are killed by carnivores of the park. Human casualties are mainly caused by sloth bear (Melursus ursinus), tiger (Panthera tigris), wild pig (Sug scrofa), and rhinoceros (Rhinoceros unicornis). There had been some earlier attempts to reconcile the conflicts by offering local people different kinds of compensations; however, these were unsuccessful measures. An integrated approach is essential if efforts to resolve the park-people conflicts are to succeed. The government is in the process of launching a project that aims to resolve the inherent problems with such an approach. Suggestions are made to incorporate some key elements, such as maintaining effective communication between various parties and the potential for wildlife conservation among local people.  相似文献   

14.
A survey was conducted in the Borana pastoral areas of southern Ethiopia to assess current livestock production systems, rangeland management practices and the perceptions of the pastoralists towards rangeland degradation. This information is considered vital to future pastoral development planning and interventions. Data were collected from a total of 20 villages that were identified from 5 peasant associations, namely Did Yabello, Moyatte, Did Harra, Dubuluk and Melbana. The average household size in the study area was 7.23. The majority of the pastoralists relied on both livestock and crop farming. The average livestock holding per household was 14 cattle, 10 goats, 6 sheep and 2 camels. Livestock holdings, with the exception of camels, has shown a declining trend over time. The two most important traditional rangeland management strategies adopted by the pastoralists included burning and mobility, but since 1974/75 burning has no longer been practised. With regard to mobility, the livestock herding falls in two categories, namely: home based and satellite herding. The former involves the herding of milking cows, calves and immature animals (<2 years) close to the encampments. The latter constitutes the herding of bulls and immatures (>2 years) further away from the encampments. Based on the pastoralists' perceptions, the major constraints on livestock production in descending order, were recurrent drought, feed and water scarcity, animal diseases, predators and communal land ownership. All the respondents considered the condition of the rangelands to have declined dramatically over time. In the past most development policies were based on equilibrium theories that opposed the communal use of the rangelands and traditional range management practices. The way in which the pastoral system affects the rangeland ecosystem functioning is contentious to this theory and the 'tragedy of the commons'. There was also a perceived problem of bush encroachment and the ban on traditional burning practices and recurrent droughts were seen as aggravating factors to this invasion process. The increasing practice of crop cultivation on the rangelands was identified as a serious threat to future livestock production and traditional resource management practices. Suggestions for possible interventions to improve the productivity and sustainable use of these rangelands are made.  相似文献   

15.
Climate change affects public land ecosystems and services throughout the American West and these effects are projected to intensify. Even if greenhouse gas emissions are reduced, adaptation strategies for public lands are needed to reduce anthropogenic stressors of terrestrial and aquatic ecosystems and to help native species and ecosystems survive in an altered environment. Historical and contemporary livestock production—the most widespread and long-running commercial use of public lands—can alter vegetation, soils, hydrology, and wildlife species composition and abundances in ways that exacerbate the effects of climate change on these resources. Excess abundance of native ungulates (e.g., deer or elk) and feral horses and burros add to these impacts. Although many of these consequences have been studied for decades, the ongoing and impending effects of ungulates in a changing climate require new management strategies for limiting their threats to the long-term supply of ecosystem services on public lands. Removing or reducing livestock across large areas of public land would alleviate a widely recognized and long-term stressor and make these lands less susceptible to the effects of climate change. Where livestock use continues, or where significant densities of wild or feral ungulates occur, management should carefully document the ecological, social, and economic consequences (both costs and benefits) to better ensure management that minimizes ungulate impacts to plant and animal communities, soils, and water resources. Reestablishing apex predators in large, contiguous areas of public land may help mitigate any adverse ecological effects of wild ungulates.  相似文献   

16.
The effects of grazing by feral horses on vegetation and dune topography at Assateague Island National Seashore were investigated using color-infrared imagery, lidar surveys, and field measurements. Five pairs of fenced and unfenced plots (300 m2) established in 1993 on sand flats and small dunes with similar elevation, topography, and vegetation cover were used for this study. Color-infrared imagery from 1998 and field measurements from 2001 indicated that there was a significant difference in vegetation cover between the fenced and unfenced plot-pairs over the study period. Fenced plots contained a higher percentage of vegetation cover that was dominated by American beachgrass (Ammophila breviligulata). Lidar surveys from 1997, 1999, and 2000 showed that there were significant differences in elevation and topography between fenced and unfenced plot-pairs. Fenced plots were, on average, 0.63 m higher than unfenced plots, whereas unfenced plots had generally decreased in elevation after establishment in 1993. Results demonstrate that feral horse grazing has had a significant impact on dune formation and has contributed to the erosion of dunes at Assateague Island. The findings suggest that unless the size of the feral horse population is reduced, grazing will continue to foster unnaturally high rates of dune erosion into the future. In order to maintain the natural processes that historically occurred on barrier islands, much larger fenced exclosures would be required to prevent horse grazing.  相似文献   

17.
A unique pastoral community uses the arid rangelands of eastern Ladakh, known as Changthang, northern India. The nomadic people rear a variety of livestock such as sheep, goats, horses and yaks, which provide them with various goods and services. Nevertheless, the needs and aspirations of the people are changing. There is a trend towards increasing the livestock population, especially of a breed of goat that produces one of the finest natural fibres: Pashmina, which is the mainstay of their economy. This increase in goat population, however, is jeopardising the long‐term survival of the wild herbivores in the region, and as such is not sustainable. We present information on the current trends in socio‐economy, Pashmina production, wildlife conservation, and the conflicts of interest between wildlife and nomads in the region. On the basis of this information, we make suggestions for the conservation of natural resources in the region. We recommend preserving the historical societal norms and notions of the people, and capitalising on them to manage natural resources. We also recommend joint management of natural resources by the local people, State and non‐governmental organisations. Our findings provide a platform on which a grazing policy for the region may be formulated.  相似文献   

18.
Conventional biodiversity surveys play an important role in ensuring good conservation friendly management in tropical forest regions but are demanding in terms of expertise, time, and budget. Can local people help? Here, we illustrate how local knowledge can support low cost conservation surveys. We worked in the Malinau watershed, East Kalimantan, Indonesia, an area currently at risk of extensive forest loss. We selected eight species of regional conservation interest: rafflesia (Rafflesia spp.), black orchid (Coelogyne pandurata), sun bear (Helarctos malayanus), tarsier (Tarsius bancanus), slow loris (Nycticebus coucang), proboscis monkey (Nasalis larvatus), clouded leopard (Neofelis diardi/N. nebulosa), and orang-utan (Pongo pygmaeus). We asked 52 informants in seven villages if, where and when they had observed these species. We used maps, based on both geo-referenced and sketched features, to record these observations. Verification concerns and related issues are discussed. Evaluations suggest our local information is reliable. Our study took 6 weeks and cost about USD 5000. Extensive expert based field surveys across the same region would cost one or two orders of magnitude more. The records extend the known distribution for sun bear, tarsier, slow loris, and clouded leopard. Reports of rafflesia, proboscis monkey, and orang-utan are of immediate conservation significance. While quality concerns should never be abandoned, we conclude that local people can help expand our knowledge of large areas in an effective, reliable, and low cost manner and thus contribute to improved management.  相似文献   

19.
ABSTRACT: Ten pairs of snow sensors were analyzed to investigate the feasibility of predicting snow water equivalent at high-elevation, telemetered snow sensor sites from lower-elevation sensors. The need for this analysis stems from an agreement between the California Department of Water Resources and the USDA Forest Service to temporarily allow snow sensors in California's wilderness areas so that a predictive relationship can be developed. After 10 or 15 years, the agreement calls for the sensors to be removed. Initial efforts to a priori select sensor pairs were based on proximity, colocation within a basin, and annual precipitation amount, but regression yielded poor fits (R2 < 0.65) and high standard errors in eight of the ten cases. Analysis of the results suggested that eleva-tional similarity was the most important selection criteria, and that all available sensors near the target site should be analyzed via a regression screening. Using elevation for selection and the regression screening, five sensors that initially had poor fits were reanalyzed. Each of the five sensors was paired with between two and five new sensors, and R2 values improved between 27 and 46 percent. Various data smoothing and editing algorithms were evaluated, but they rarely resulted in improved fits.  相似文献   

20.
Environmental, biological, socio-cultural and economic variations in the Himalayas have led to the evolution of diverse and unique traditional agroecosystems, crop species, and livestock, which help the traditional mountain farming societies to sustain themselves. During the recent past, as a result of rapid changes in land use caused by socio-cultural and economic changes and various environmental perturbations, the agrobiodiversity of the Central Himalayan agroecosystems has changed steadily. A recent survey conducted in 150 different villages located along an elevated transect of the Alaknanda catchment of the Central Himalaya revealed that over a period of two decades (1970–74 and 1990–94) the cultivated area under many traditional crops had declined significantly. A micro-level study carried out in 30 villages revealed that a series of changes had occurred in land use practices over a period of 25–30 years.The loss of agrobiodiversity and the changing socio-cultural and economic dimensions and their impacts on the sustainability of Himalayan agroecosystems are emerging as major causes of concern at local/regional/national scale, and appropriate options to meet these challenges are discussed in this paper.  相似文献   

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