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951.
Interactions between humans and wildlife resulting in negative impacts are among the most pressing conservation challenges globally. In regions of smallholder livestock and crop production, interactions with wildlife can compromise human well-being and motivate negative sentiment and retaliation toward wildlife, undermining conservation goals. Although impacts may be unavoidable when human and wildlife land use overlap, scant large-scale human data exist quantifying the direct costs of wildlife to livelihoods. In a landscape of global importance for wildlife conservation in southern Africa, we quantified costs for people living with wildlife through a fundamental measure of human well-being, food security, and we tested whether existing livelihood strategies buffer certain households against crop depredation by wildlife, predominantly elephants. To do this, we estimated Bayesian multilevel statistical models based on multicounty household data (n = 711) and interpreted model results in the context of spatial data from participatory land-use mapping. Reported crop depredation by wildlife was widespread. Over half of the sample households were affected and household food security was reduced significantly (odds ratio 0.37 [0.22, 0.63]). The most food insecure households relied on gathered food sources and welfare programs. In the event of crop depredation by wildlife, these 2 livelihood sources buffered or reduced harmful effects of depredation. The presence of buffering strategies suggests a targeted compensation strategy could benefit the region's most vulnerable people. Such strategies should be combined with dynamic and spatially explicit land-use planning that may reduce the frequency of negative human–wildlife impacts. Quantifying and mitigating the human costs from wildlife are necessary steps in working toward human–wildlife coexistence.  相似文献   
952.
城市绿地系统生物多样性保护的策略探讨   总被引:57,自引:1,他引:56  
生物多样性是提高城市绿地系统生态功能的前提和城市多样化景观的基础。通过保护自然遗留地,建立绿色生态网络,开发利用地带性物种,尤其是乡土植物,并有节制地引进外域特色樾的,扩大多样性物种的种群增加绿地规模,促进公园和环城绿带的自然化,营造生物多样性高的复层群落结构,形成具有地域性植被征的城市生物多样性格局提高绿地系统的生物多样性。  相似文献   
953.
新疆北部沙漠边缘植被恢复可能性初探   总被引:2,自引:0,他引:2  
古尔班通古特沙漠边缘植被破坏严重,沙丘活化明显,是新疆干旱植被恢复的重点地区之一,一般缺乏地表水补充,其沙丘的水分状况便成为植被生存和恢复过程的关键条件,为探究古尔班通古特沙漠边缘植被恢复的可能性,在植物生长期内对流动沙丘和固定沙丘不同部位的水分状况进行了连续监测,结果表明:沙丘大多数层次含水量月变化与月降水量分布相一致;流动沙丘含水量从上部到下部依次升高;流动沙丘中部和下部稳定湿沙层处在距沙丘表面60 cm以下,且厚度超过100 cm,固定沙丘稳定湿沙层只存在于沙丘中部距沙丘表面60~150 cm内,其厚度不超过100 cm,在一般年份,该地区利用本地种进行植被恢复是可行的.  相似文献   
954.
The Mekong River Basin is considered to be the second most species rich river basin in the world. The 795,000 km(2) catchment encompasses several ecoregions, incorporating biodiverse and productive wetland systems. Eighty percent of the rapidly expanding population of the Lower Mekong Basin (LMB), made up in part by Lao PDR, Thailand, Cambodia and Viet Nam, live in rural areas and are heavily reliant on wetland resources. As the populations of Cambodia and Lao PDR will double in the next 20 years, pressure on natural resources and particularly wetlands can only increase. For development planning, resource and conservation management to incorporate wetland issues, information on the distribution and character of Mekong wetlands is essential. The existing but outdated wetland maps were compiled from secondary landuse-landcover data, have limited coverage, poor thematic accuracy and no meta-data. Therefore the Mekong River Commission (MRC) undertook to produce new wetland coverage for the LMB. As resources, funding and regional capacity are limited, it was determined that the method applied should use existing facilities, be easily adaptable, and replicable locally. For the product to be useful it must be accepted by local governments and decision makers. The results must be of acceptable accuracy (>75%) and the methodology should be relatively understandable to non-experts. In the first stage of this exercise, field survey was conducted at five pilot sites covering a range of typical wetland habitats (MRC wetland classification) to supply data for a supervised classification of Landsat ETM images from the existing MRC archive. Images were analysed using ERDAS IMAGINE and applying Maximum Likelihood Classification. Field data were reserved to apply formal accuracy assessment to the final wetland habitat maps, with resulting accuracy ranging from 77 to 94%. The maps produced are now in use at a Provincial and National level in three countries for resource and conservation planning and management applications, including designation of a Ramsar wetland site of international importance.  相似文献   
955.
Cutleaf coneflower (Rudbeckia laciniata L.) seedlings were placed into open-top chambers in May, 2004 and fumigated for 12 wks. Nine chambers were fumigated with either carbon-filtered air (CF), non-filtered air (NF) or twice-ambient (2×) ozone (O3). Ethylenediurea (EDU) was applied as a foliar spray weekly at 0 (control), 200, 400 or 600 ppm. Foliar injury occurred at ambient (30%) and elevated O3 (100%). Elevated O3 resulted in significant decreases in biomass and nutritive quality. Ethylenediurea reduced percent of leaves injured, but decreased root and total biomass. Foliar concentrations of cell-wall constituents were not affected by EDU alone; however, EDU × O3 interactions were observed for total cell-wall constituents and lignocellulose fraction. Our results demonstrated that O3 altered the physiology and productivity of cutleaf coneflower, and although reducing visible injury EDU may be phytotoxic at higher concentrations.  相似文献   
956.
选择青藏高原多年冻土区工程迹地的人工恢复植物和紫花针茅草原的优势植物以及对应的土壤样品进行对照,利用原子吸收法分析了它们的矿质元素含量特征。结果表明:多年冻土区工程迹地人工恢复区植物的元素含量:>1 000 μg/g的元素有Ca、P和Na,100~1 000 μg/g的元素有Mn、K、Fe、Mg和Al;而对照紫花针茅草原优势植物的元素含量:>1 000 μg/g的元素有Ca和Na,100~1 000 μg/g的元素有P、Mn、K、Fe、Mg和Al。人工恢复区土壤元素含量:>1 000 μg/g的元素有Ca、Fe和Mn,100~1000 μg/g的元素有Mg、K、Al、P和Na;对照紫花针茅草原土壤元素含量:>1 000 μg/g的元素有Ca、Fe,100~1 000 μg/g的元素有Mn、Mg、Al、K、P和Na。该区域植物和土壤元素含量都属于Ca > K 型。人工恢复植物和对照的紫花针茅草原植物对土壤元素的吸收能力具有较高的相似性。K和Al元素的累积与其他元素没有显著的相关关系,其他元素之间为正相关关系,元素之间的吸收累积属于协同作用,无明显的撷抗作用  相似文献   
957.
作为未来一段时期市场化减排政策的重要抓手,中国将于2017年启动全国碳交易市场。通过施加碳价格,碳市场将对不同行业的生产成本产生影响。那么,碳价格对中国工业外商直接投资的影响如何?是否有助于优化吸引FDI的行业结构?这正是本文关注的焦点。为了克服碳价格数据不足的问题,本文构建了碳价格与煤炭、天然气等五种能源价格之间的映射关系,并采用1999—2013年36个工业行业的面板数据,估计了能源成本对外商直接投资相对规模和绝对规模的影响,并通过碳市场不同价格水平与能源成本之间的映射关系,对工业行业吸引FDI的潜在影响进行了反事实测算。论文的主要结果有:(1)碳价格与能源成本之间的映射关系存在行业异质性,这是由不同工业行业的能源消费结构差异所致。(2)能源成本对整体FDI的规模不存在显著负向影响。其对中国吸引FDI的相对规模和绝对规模的影响在高耗能行业和非高耗能行业间存在显著的差异。(3)不同碳价格水平对中国工业吸引FDI的相对规模、绝对规模和行业结构都将产生显著影响。碳价格将显著降低高耗能行业的FDI规模,但对非高耗能行业的外资规模具有促进作用;对FDI的绝对规模的影响较之相对规模更显著。碳价格为50元时,高耗能行业FDI的相对规模累积下降2%—7%,绝对规模累积下降3%—13%;非高耗能行业FDI的相对规模累积增加1.5%—3%,绝对规模累积增加0.1%—0.3%。上述结果说明,全国碳市场建立对中国工业吸引FDI的整体规模不会产生显著的负面影响,但有助于提高非高耗能行业的FDI流入,并降低高耗能行业的FDI流入,优化工业吸引外资的行业结构。  相似文献   
958.
Spatially explicit integrated assessment of ecosystem services is a new and important research field in landscape ecology. The objective of this paper was to develop an integrated process-based modeling method to simulate changes in multiple ecosystem services in 2000–2009 at pixel and regional scales in the Zhangye oasis of northwestern China. Six ecosystem service indicators were selected and quantified using process-based models, including net primary production (NPP), grain production, net oxygen production (NOP), carbon sequestration (CS), water conservation, and soil conservation. Analytical results were as follows: (1) At the oasis scale, NPP, NOP, CS, water conservation, and soil conservation decreased from 2000 to 2009, whereas grain production increased. (2) At the pixel scale, the spatial changes in NPP were similar to those in NOP and CS, but changes in grain production showed the opposite pattern. Water conservation and soil conservation showed somewhat unintuitive spatial patterns. (3) The impact of land-use forms on ecosystem services showed that grazing and township construction both had negative impacts on all services, but that nature conservation and wetland development had positive impacts on all services. This research showed that the integrated modeling can be proposed as an environmental decision-making tool in similar case studies.  相似文献   
959.
付秀琪  唐斌  陈敏 《四川环境》2012,31(2):91-93
本文将通过NOAA气象卫星提供的AVHRR遥感数据,反演吉林省西部地区各项地表参数,进而为吉林省西部地区生态环境变化的研究提供新的依据,从而达到改善研究区生态环境恶化的现状,推动吉林西部地区经济的可持续发展。  相似文献   
960.
Modelling agronomic properties of Technosols constructed with urban wastes   总被引:2,自引:0,他引:2  
The greening of urban and suburban areas requires large amounts of arable earth that is a non-renewable resource. However, concentration of population in cities leads to the production of high amounts of wastes and by-products that are nowadays partly recycled as a resource and quite systematically exported out of urban areas. To preserve natural soil resources, a strategy of waste recycling as fertile substitutes is proposed. Eleven wastes are selected for their environmental harmlessness and their contrasted physico-chemical properties for their potential use in pedological engineering. The aim is (i) to demonstrate the feasibility of the formulation of fertile substrates exclusively with wastes and (ii) to model their physico-chemical properties following various types, number and proportions of constitutive wastes. Twenty-five binary and ternary combinations are tested at different ratios for total carbon, Olsen available phosphorus, cation exchange capacity, water pH, water retention capacity and bulk density. Dose–response curves describe the variation of physico-chemical properties of mixtures depending on the type and ratio of selected wastes. If these mixtures mainly mimic natural soils, some of them present more extreme urban soil features, especially for pH and POlsen. The fertility of the new substrates is modelled by multilinear regressions for the main soil properties.  相似文献   
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