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1.
Biodiversity is a critical component of the natural environment and the protection of it often meant the displacement of local communities in developing countries. The Richtersveld National Park (South Africa) is unusual in that it forms part of the Richtersveld communal rangeland and is currently managed for goat and sheep farming as well as biodiversity conservation under a contractual agreement. These two objectives are not regarded as mutually compatible and have created tension between conservation management officials and pastoralists. We set out to examine the consequences of reducing herd size in a communal livestock production system in support of biodiversity conservation in a protected area. Kidding, animal offtake (sales and slaughter), mortality and herd persistence showed no clear incentives for an individual pastoralist to reduce herd size. Reducing herd size is not considered a recommended intervention for the conservation of biodiversity or livelihood improvement of pastoralists in the park. The future of the natural resources of the national park is dependent on a delicate balance between the needs of the pastoralists and the conservation of those very same resources that the pastoralists use. 相似文献
2.
Livestock grazing is the most common use of rangelands, and overgrazing by domestic livestock has stirred much debate concerning the continued use of public rangelands for livestock production. With the increase of wildlife-related enterprises on south Texas rangelands, there are little data available on the compatibility of livestock and wildlife management and in particular the effects of livestock grazing on plant communities in the semi-arid portions of the western South Texas Plains. The objective of this study was to compare forb diversity and density on rangelands subjected to various grazing under a high-intensity, low-frequency grazing system and nongrazed rangelands under controlled conditions. Four rangeland sites that were moderately grazed during the dormant season and 4 rangeland sites receiving long-term deferment from grazing were selected on the Chaparral Wildlife Management Area, Dimmit and La Salle Counties, Texas. Forb density was estimated with 20×50 cm2 quadrats during early spring 2000 and 2001. Forb diversity was greatest on grazed sites. Important annuals such as hooker plantain (Plantago hookeriana) and Rough buttonweed (Diodia teres) were more prevalent on grazed sites. Lazy daisy (Aphanostephus spp.) was more frequently encountered on nongrazed sites. Golden dalea (Dalea aurea), a beneficial perennial, was more common on grazed sites. Long-term deferment from livestock grazing appears detrimental to forb communities. A high-intensity, low-frequency grazing system utilizing moderate stocking rates employed during the dormant season is recommended for enhancing forb diversity and abundance. 相似文献
3.
Charles W. Slaughter 《国际泥沙研究》2000,(2)
lINTRODUCTIONRangeandforestlandsofnorthwesternNorthAmericahavebeenutilizedforres0urceextracti0nandproductionsinceinitialhuman0ccupationofthecontinent.Intensive"managed"utilizati0nofec0systemsforspecificbenefitsincludingcattle,sheep,t1sh,w00dandagriculturalpr0ductshasbeenong0ingfornearly0ne-and-haIfcenturies.Intensiveresourceproducti0nhasto0oftenbeenacc0mpaniedbyunwanted"sideeffects"includingacceleratederosion,s0illossandsedimentdeliveredoffsitetod0wnstreamlocati0ns,estuariesandoceanicsin… 相似文献
4.
Vast areas of rangelands across the world are grazed with increasing intensity, but interactions between livestock production, biodiversity and other ecosystem services are poorly studied. This study explicitly determines trade-offs and synergies between ecosystem services and livestock grazing intensity on rangelands. Grazing intensity and its effects on forage utilization by livestock, carbon sequestration, erosion prevention and biodiversity are quantified and mapped, using global datasets and models. Results show that on average 4% of the biomass produced annually is consumed by livestock. On average, erosion prevention is 10% lower in areas with a high grazing intensity compared to areas with a low grazing intensity, whereas carbon emissions are more than four times higher under high grazing intensity compared to low grazing intensity. Rangelands with the highest grazing intensity are located in the Sahel, Pakistan, West India, Middle East, North Africa and parts of Brazil. These high grazing intensities result in carbon emissions, low biodiversity values, low capacity for erosion prevention and unsustainable forage utilization. Although the applied models simplify the processes of ecosystem service supply, our study provides a global overview of the consequences of grazing for biodiversity and ecosystem services. The expected increasing future demand for livestock products likely increase pressures on rangelands. Global-scale models can help to identify targets and target areas for international policies aiming at sustainable future use of these rangelands. 相似文献
5.
This paper examines the incentives driving expansion of rangeland enclosure. It explores the role of customary authorities in defining and enforcing rights to private use of land and attempts to scrutinize whether informal rules emerge to respond to these needs and even become an incentive to establish private enclosures as well as to delineate the processes and actors involved. Based on household level data and group discussion with customary leaders and state agents, results indicate that there are endogenous and exogenous driving forces for range enclosure and change in land use. Institutional diversity is inherent across the cases studied, where this is closely linked to the nature of benefits from enclosure and the underlying incentives. Though signs of state support for enclosure are evident via assessing the role of lower level state administrators in allocation of land for private grazing, policy support for private land use cannot fully explain the gradual shift in de facto property rights. The role of socio-economic and ecological changes is much more important and has widespread influence, where the influence of the former emerges from the economic changes taking place in the rest of the economy, including the rising livestock price. 相似文献
6.
Desertification in the Sahel: Towards better accounting for ecosystem dynamics in the interpretation of remote sensing images 总被引：3，自引：0，他引：3
L. Hein N. de RidderP. Hiernaux R. LeemansA. de Wit M. Schaepman 《Journal of Arid Environments》2011,75(11):1164-1172
To date, the interpretation of remote sensing images has not revealed wide-spread degradation of the vegetation in the Sahel. However, the interpretation of spectral information depends on a range of assumptions regarding the dynamics of the Sahelian vegetation as a function of rainfall variability and human management. Recent papers have presented diverging views on the vegetation dynamics of the Sahel and how these can be analysed with remote sensing images. We present a further analysis of the vegetation dynamics of semi-arid rangelands, in particular the Sahel, and the subsequent implications for the interpretation of remote sensing images. Specifically, the ecological processes driving the response of the Sahelian vegetation to rainfall variation are re-examined, and a regression analysis of NPP versus rainfall data is carried out. It is shown that the relation between the interannual variation in NPP and rainfall in the Sahel is non-linear and that this relation differs between sites with different average annual rainfall. It has been common practise in remote sensing studies for the Sahel to aggregate data from various Sahelian sites in order to obtain an average relation between rainfall, NPP and Rain Use Efficiency, and to assume these relations to be linear. This paper shows that this approach may lead to a bias in the interpretation of remote sensing images and that further work is required to clarify if wide-spread ecosystem degradation has occurred in the Sahel. 相似文献
7.
适应性治理与气候变化：内蒙古草原案例分析与对策探讨 总被引：1，自引：0，他引：1
适应性治理通过边学边做,针对各地方的社会经济条件、自然生态系统、地方知识文化等基本特征,基于一个动态、自下而上和自组织的过程不断测试和修正制度安排与知识体系,形成一个旨在解决实际问题的循环过程。通过内蒙古3个地区案例的对比分析研究,基于对其气候变化风险和社会脆弱性的评估,发现其在气候变化影响下形成的不同程度的社会脆弱性正是源于不同的草原利用机制和基于此的社会合作机制。正是因为3个案例地的牧民有着不同的社会资本和社会记忆,所以他们面对极端天气导致的自然灾害时,采取了不同的应对方式,有的牧户可以依赖于社会资本移动牲畜来渡过难关,有的牧户则可以在嘎查范围内重启社会记忆,通过合理安排草场利用和移动牲畜提高自身的抗灾能力,而有的牧户则只能通过买草料独立抗灾。这样不同的结果有力证明了适应性治理在提升这些地区气候变化应对能力方面的必要性和可行性。在地区层面引入适应性治理,可以满足各利益相关方的需求,有利于自然、社会及管理的多学科协同,与“未来地球计划”的协同设计、协同实施和协同推广理念不谋而合,是“未来地球”思想在气候变化适应研究中的实践。 相似文献
8.
赵玲 《沙漠与绿洲气象(新疆气象)》2015,9(2):57-62
本研究建立基于MODIS的天山山区草地类型植被指数并分析其与气候因子的关系,研究发现：天山山区NDVI分布北部大,南部小;西部大,东部小。降水是影响天山山区NDVI的主要因子。天山山区在温度上升0.1℃,面雨量增加10%的情况下,NDVI增加2.5%。2000~2009年天山山区NDVI年平均值为0.35,温度呈上升趋势,降水呈减少趋势,对植被的生长不利,NDVI呈现出减小趋势,但减小不明显。天山山区NDVI最大值的年份,降水并不是最多的,说明植被的长势需要水分和热量匹配。1961~2009年天山山区的气候变化有利于草地NDVI的增加 相似文献
9.
Land use and climate change could have huge impacts on food security and the health of various ecosystems. Leaf nitrogen (N) and above-ground biomass are some of the key factors limiting agricultural production and ecosystem functioning. Leaf N and biomass can be used as indicators of rangeland quality and quantity. Conventional methods for assessing these vegetation parameters at landscape scale level are time consuming and tedious. Remote sensing provides a bird-eye view of the landscape, which creates an opportunity to assess these vegetation parameters over wider rangeland areas. Estimation of leaf N has been successful during peak productivity or high biomass and limited studies estimated leaf N in dry season. The estimation of above-ground biomass has been hindered by the signal saturation problems using conventional vegetation indices. The objective of this study is to monitor leaf N and above-ground biomass as an indicator of rangeland quality and quantity using WorldView-2 satellite images and random forest technique in the north-eastern part of South Africa. Series of field work to collect samples for leaf N and biomass were undertaken in March 2013, April or May 2012 (end of wet season) and July 2012 (dry season). Several conventional and red edge based vegetation indices were computed. Overall results indicate that random forest and vegetation indices explained over 89% of leaf N concentrations for grass and trees, and less than 89% for all the years of assessment. The red edge based vegetation indices were among the important variables for predicting leaf N. For the biomass, random forest model explained over 84% of biomass variation in all years, and visible bands including red edge based vegetation indices were found to be important. The study demonstrated that leaf N could be monitored using high spatial resolution with the red edge band capability, and is important for rangeland assessment and monitoring. 相似文献
10.
A. Ouled Belgacem M. Neffati V.P. Papanastasis M. Chaieb 《Journal of Arid Environments》2006,65(4):682-687
Native grass species are being considered in the restoration of degraded rangelands in Tunisia due to the failure of introduced species to adapt to the ecological constraints of the region. The objective of this study was to determine the effects of seed age and seedling depth on emergence and seedling vigor of Stipa lagascae, a perennial bunchgrass that is native to the region and shows promise as a species for restoration purposes. Total emergence percentage of seedlings and the coefficient of rate of emergence (CRE), the seedling vigour as well as above and below-ground biomass were measured. Younger seeds had higher emergence rates than older seeds. However, seed age did not affect variables associated with seedling vigour. Seeding depth significantly affected all parameters tested. A seeding depth of 4–6 cm was found to be optimal. 相似文献