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1.
新疆于田绿洲生态弹性度与景观环境分析   总被引:8,自引:0,他引:8  
利用遥感资料和模型定量估算了新疆于田绿洲生态弹性度和生态景观的变化。结果表明:1976-1999年荒漠不断减少,草地面积大幅度增加以及水体的适量扩大,该绿洲生态系统的生态弹性度逐年提高,生态系统对扰动和压力的缓冲与调节能力不断增强。这一方面有效地防止土地沙漠化,减少了风沙危害,同时促进了绿洲生态系统的稳定和健康发展。  相似文献
2.
Climate change creates new challenges for biodiversity conservation. Species ranges and ecological dynamics are already responding to recent climate shifts, and current reserves will not continue to support all species they were designed to protect. These problems are exacerbated by other global changes. Scholarly articles recommending measures to adapt conservation to climate change have proliferated over the last 22 years. We systematically reviewed this literature to explore what potential solutions it has identified and what consensus and direction it provides to cope with climate change. Several consistent recommendations emerge for action at diverse spatial scales, requiring leadership by diverse actors. Broadly, adaptation requires improved regional institutional coordination, expanded spatial and temporal perspective, incorporation of climate change scenarios into all planning and action, and greater effort to address multiple threats and global change drivers simultaneously in ways that are responsive to and inclusive of human communities. However, in the case of many recommendations the how, by whom, and under what conditions they can be implemented is not specified. We synthesize recommendations with respect to three likely conservation pathways: regional planning; site-scale management; and modification of existing conservation plans. We identify major gaps, including the need for (1) more specific, operational examples of adaptation principles that are consistent with unavoidable uncertainty about the future; (2) a practical adaptation planning process to guide selection and integration of recommendations into existing policies and programs; and (3) greater integration of social science into an endeavor that, although dominated by ecology, increasingly recommends extension beyond reserves and into human-occupied landscapes.  相似文献
3.
喀斯特地区土地利用变化的生态服务功能价值响应   总被引:4,自引:0,他引:4       下载免费PDF全文
频繁发生的旱灾已成为限制我国西北半干旱区农业发展和生态环境建设的主要气象因子.以甘肃省榆中县为例,基于农户问卷调查,结合GIS技术,从社会、经济和生态三个角度选择水分敏感因子,构建社会-生态系统,然后根据修正的脆弱度概念性模型计算出干旱环境下农户尺度上社会一生态系统恢复力,并对造成恢复力差异的原因进行了分析.结果表明,榆中县农户社会生态系统对干旱的恢复力依赖于外部胁迫压力(干旱)和内部因素(社会,经济,生态)之间的相互作用.户人口数量、土壤湿度和土壤养分是3个区域农户社会-生态系统共同的水分敏感因子;而其它指标则属于局部区域农户社-生态系统的水分敏感因子.  相似文献
4.
露天矿生态承载力的变化与矿区的污染控制、土地复垦与生态重建措施密切相关。本文根据矿区生态承载力内涵及层次特点, 从生态系统弹性力、资源环境承载力及生态系统压力度3个方面提出对其进行量化的研究方法。结合高吉喜提出的生态承载力评价方法, 构建了较完整的评价指标体系, 利用AHP法求得各指标权重值, 对矿区生态承载力状况进行静态和动态评价。研究结果表明: 平朔安太堡矿区2007年的生态系统弹性力为46.836, 中等稳定; 资源环境承载力47.127, 中等承载; 生态系统压力度为1.396, 承载超负荷。从动态变化趋势看, 平朔安太堡矿区生态系统弹性力波动较强烈, 说明矿区生态系统稳定性差, 具有明显的脆弱特性; 生态系统压力指数的变化说明, 1999年前生态系统的压力对矿区生态系统弹性力和资源环境承载力影响较大, 而1999年后影响逐渐减弱, 矿区1987~2007年生态系统弹性力和资源环境承载力变化趋势相同; 1997年后生态弹性力开始上升, 资源环境承载力在1999年后也处于明显上升趋势。  相似文献
5.
应用危险确认模型评估土地管理的可持续发展   总被引:1,自引:1,他引:4  
New Zealand is highly dependent on its soil resource for continued agricultural production.To avoid depleting this resource,there is a need to identify soils and associated land management practices where there is a risk of soil degradation.Environmental integraity and ecosystem services also need to be maintoained.Accordingly,to ensure sustainable production,The on -and off-site environmental impacts of aldn management need to be identified and managed.We developed a structural vulnerability index for New Zealand soils.This index ranks solis according to their inherent susceptibility to physical degradation when used for agricultural (pasture,forestry and cropping) Purposes.We also developed a rule-based model to assess soil sompaction vulnerability by characterising the combined effects of resistance and resilience,Other soil attributes have been approatised using seven chemical,physical and biological indicators of soil quality.These indicators have been applied in a nation -wide project involving data collection from over 500 sites for a range of land uses.These soil quality data can be interpreted via the World Wide Web -through the in teractive decisionsupport tool SINDI,The land-use impact model is a framework to assess agricultural land management and environmental sustainability,and may be applied to land units at any scale.Using land resource data and information the model explicitly identifies hazards to land productivity and environmental integrity,It utilises qualitative expert and local knowledge and quantitative model-based evaluations to assess the potential environmental impacts of land-management pratices.The model is linked to a geographic information system(GIS),allowing model outputs.such at the environmental impacts of site-specific best management practices,to be identified in a spatially explicit manner,The model has been tested in New Zealand in an area of pastoral land use.Advantages of this risk identification model include:utilising current knowledege of the causes and effects of land-management practices on soil degradation;linking land management practice to both on-and off-site environmental consequences;identifying important gaps in local knowledge,and providing spatially explicit information on the environmental impact of land-management practices.  相似文献
6.
The microbial functioning of soils following perturbation was assessed at a temperate upland grassland site, maintained by the Soil Biodiversity and Ecosystem Function Programme at Sourhope Research Station, Scotland. Published results indicated that the soil microbial communities were resilient to these initial perturbations; in this paper we tested whether they were equally resilient to a subsequent perturbation. Soil samples were taken from field plots receiving treatments that represented different forms of perturbation, viz. reseeding, application of sewage-sludge, biocide or nitrogen plus lime, and a non-perturbed control. Functional resilience following further perturbation comprising a transient heat or persistent copper perturbation was assessed over 28 days, by monitoring the short-term decomposition of added plant residues. Bacterial community structure was assessed by DGGE separation of eubacterial 16S rDNA PCR products. PCR-DGGE did not distinguish any significant difference (P>0.05) between the bacterial communities of soils under different treatments, showing differences only between treated soils and the untreated, control soils.Two days after the application of stresses, functional capability differed in soils under different treatments. Soil samples from all the treated plots were less resilient to heat stress than soil from control plots. The initial reduction in decomposition following the addition of copper differed between treatments, but function had not recovered in any of the Cu-amended soils within 28 days. Soil resilience varied according to the type and duration of stress applied, microbial activity, soil characteristics and treatment regimes. The initial resistance of function to stress was not predictive of recovery of function over time.  相似文献
7.
[目的]为了探讨艾比湖流域近10a间景观格局及生态安全的动态变化。[方法]运用RS和GIS技术,并结合景观指数和生态弹性度对该流域生态安全进行了综合评价。[结果](1)近10a来,艾比湖流域土地利用变化剧烈,说明景观格局持续受社会经济发展两方面矛盾的巨大压力;(2)2001年斑块个数为2 560个,而2009年增加至3 476个,说明该流域生态环境整体呈破碎化趋势。景观破碎度由2001年的0.054 0增加为2009年的0.073 3,说明其景观趋于不稳定,生态安全性降低;(3)2001—2009年生态弹性度呈"∧"型变化趋势,先由2001年的1.20×107增加为2005年的1.57×107,然后再降为2009年的1.49×107,但总体是趋于增大的趋势。[结论]从整体上综合考虑,2001—2009年艾比湖流域土地利用的景观生态安全度降低。  相似文献
8.
本文回顾了农业旱灾系统恢复性研究进展, 探讨了灌溉农区农业旱灾系统恢复性基本问题, 提出了其恢复性评价思路与框架, 建立了综合指数评价模型, 并以河北省邢台市为例进行了评估。结果表明, 在生长季或年际尺度上, 自然降水偏少对全市旱情有显著影响, 但并不决定最终灾情。旱灾严重程度和系统恢复能力还受到农业资源环境基础、旱灾应对能力及社会经济发展水平等多方面因素影响。持续超采浅层地下水进行灌溉的中部平原地带的县市, 农业旱灾系统恢复指数较高; 缺水、人均耕地资源不足且经济相对落后的西部山地丘陵地区各县市农业旱灾系统恢复指数较低; 在深层地下水超采、地下水漏斗扩展的东部地区, 取水能力强,经济承受力较高的县市, 农业旱灾系统恢复指数较高, 经济落后的县, 恢复指数最低。在生长季或年际尺度上,虽然以水资源持续超采进行灌溉, 全市旱灾总体恢复能力在提高, 但因其忽视了区域水平衡和生态稳定性,所以不具有可持续性。  相似文献
9.
The extent to which secondary forests occupying degraded and abandoned lands provide suitable habitat for forest-adapted species is an important conservation issue in times of vanishing old growth forests. We used ants (Hymenoptera: Formicidae), a functionally important and diverse group of invertebrates, to investigate the recovery of soil taxa during secondary forest succession in the Atlantic Forest of Southern Brazil. We compared the resilience of epigeic vs. hypogeic ant assemblages. For this purpose we established 27 sites that encompassed a chronosequence from pastures to old growth forests on two contrasting soil types. Our results are based on a collection of 35 508 individuals in 40 genera.Richness and composition of ant assemblages in secondary forests have recovered slowly and have not approached conditions typical of old growth forests. The distribution of genera along the successional stages was arranged in a nested pattern where ant genera of younger successional stages were a subset of genera present in older stages. Edaphic conditions had no influence on the recovery process. Overall, richness of ants was lower at study sites with water-logged soils than at sites where soils did not exhibit hydromorphic properties. The hypogeic ant assemblage recovered more slowly than the epigeic assemblage.Our results show that secondary forests do not act as refuges for many forest-adapted animals which are currently restricted to discontinuous patches of old growth forest in the highly endangered Atlantic Forest of Brazil. Moreover, estimated recovery times of 50 to several hundred years suggest it would take much longer than previously presumed for complete recolonization.  相似文献
10.
Effects of clear-cutting on biodiversity have mainly been studied in the short-term, although knowledge of longer term effects are often more important for managers of forest biodiversity. We assessed relatively long-term effects of clear-cutting on litter dwelling land snails, a group with slow active dispersal and considered to be intolerant to microclimate changes. In a pair wise design we compared snail abundance, species density, and species composition between 13 old seminatural stream-side stands and 13 matched young stands developed 40-60 years after clear-cutting. Using a standardized semi-quantitative method, we identified all snail specimens in a 1.5 l subsample of a pooled litter sample collected from small patches within a 20 × 5 m plot in each stream-side stand. From the young stands a mean of 135 shells and 9.5 species was extracted which was significantly higher than the 58.1 shells and 6.9 species found in old forests. Only two of the 16 species encountered showed a stronger affinity to old than to young forests. In short-term studies of boreal stream-side forests land snail abundance is reduced by clear-cutting. Our results indicate that this decline is transient for most species and within a few decades replaced by an increase. We suggest that local survival in moist stream-side refugia makes the land snails able to benefit from the higher pH and more abundant non-conifer litter in young than in old boreal forests. Our results highlight the importance of longer term studies as a basis for management guidelines for biodiversity conservation.  相似文献
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