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The Greater Yellowstone Ecosystem   总被引:1,自引:0,他引:1  
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Every winter, government agencies feed approximately 6000 metric tons (6 x 10(6) kg) of hay to elk in the southern Greater Yellowstone Ecosystem (GYE) to limit transmission of Brucella abortus, the causative agent of brucellosis, from elk to cattle. Supplemental feeding, however, is likely to increase the transmission of brucellosis in elk, and may be affected by climatic factors, such as snowpack. We assessed these possibilities using snowpack and feeding data from 1952 to 2006 and disease testing data from 1993 to 2006. Brucellosis seroprevalence was strongly correlated with the timing of the feeding season. Longer feeding seasons were associated with higher seroprevalence, but elk population size and density had only minor effects. In other words, the duration of host aggregation and whether it coincided with peak transmission periods was more important than just the host population size. Accurate modeling of disease transmission depends upon incorporating information on how host contact rates fluctuate over time relative to peak transmission periods. We also found that supplemental feeding seasons lasted longer during years with deeper snowpack. Therefore, milder winters and/or management strategies that reduce the length of the feeding season may reduce the seroprevalence of brucellosis in the elk populations of the southern GYE.  相似文献   

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Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.  相似文献   

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Land use is rapidly expanding in the Greater Yellowstone Ecosystem, primarily from growth in the number of rural homes. There is a need to project possible future land use and assess impacts on nature reserves as a guide to future management. We assessed the potential biodiversity impacts of alternative future land use scenarios in the Greater Yellowstone Ecosystem. An existing regression-based simulation model was used to project three alternative scenarios of future rural home development. The spatial patterns of forecasted development were then compared to several biodiversity response variables that included cover types, species habitats, and biodiversity indices. We identified the four biodiversity responses most at risk of exurban development, designed growth management policies to protect these areas, and tested their effectiveness in two alternative future scenarios. We found that the measured biodiversity responses, including riparian habitat, elk winter range, migration corridors, and eight other land cover, habitat, and biodiversity indices, are likely to undergo substantial conversion (between 5% and 40%) to exurban development by 2020. Future habitat conversion to exurban development outside the region's nature reserves is likely to impact wildlife populations within the reserves. Existing growth management policies will provide minimal protection to biodiversity in this region. We identified specific growth management policies, including incentives to cluster future growth near towns, that can protect "at risk" habitat types without limiting overall growth in housing.  相似文献   

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Finding Hope in the Millennium Ecosystem Assessment   总被引:1,自引:0,他引:1  
Abstract:  Over the past quarter century, a new scientific activity has emerged: collective assessments by large numbers of scientists from different disciplines combining their expertise to better understand human interrelations with nature and to inform policy. The Millennium Ecosystem Assessment exceeded all such assessments before it in both the breadth of its coverage and the depth of its analysis of socioecological system dynamics. The findings are not encouraging. Nearly all ecosystems are being degraded and will continue to be degraded for decades to come even if policy changes are initiated now. For scientists participating in the assessment, the MA had another disconcerting aspect. It clearly shows that our fragmented, disciplinary knowledges cannot simply be combined to form an understanding of a whole complex system. Counterbalancing the despair of the findings and scientific difficulties of aggregating specialized knowledges, the MA demonstrated the potential of a deliberative democratic approach to grappling with complex problems .  相似文献   

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大连市森林生态系统服务功能评估   总被引:1,自引:0,他引:1  
为客观度量森林生态系统服务功能,依据2003年大连市土地利用图形数据,参照国家林业局发布的《森林生态系统服务功能评估规范》(LY/T1721-2008)标准中的评估方法,基于G IS技术对大连市森林生态系统服务功能及其空间差异性进行定量评价。结果表明:(1)大连市森林生态系统服务功能的经济价值总计为197.91亿元/a,其中涵养水源、保育土壤、固碳释氧、净化大气4种生态服务功能的经济价值比例分别为35.3%、16.7%、43.0%、5.0%;(2)大连市的生态屏障庄河市、普兰店市和瓦房店市具有显著的森林生态系统服务功能,其价值比例分别为32.6%、21.8%和25.8%,而长海县、金州区、旅顺口区、甘井子区、沙河口区、中山区、西岗区森林生态系统服务功能的经济价值比例分别为0.9%、7.8%、5.7%、3.9%、0.2%、0.5%和0.7%。  相似文献   

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生态系统健康评价研究进展   总被引:15,自引:1,他引:15  
介绍了生态系统健康概念的发展状史以及生态系统健康学的主要研究内容,阐述了生态系统健康评价与环境管理的关系,建立了生态系统健康评价指标体系。  相似文献   

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2007年7月~2008年5月按季度对丹江口水库4个库区(丹江库区、汉江库区、取水口和五青入库区)的水环境和浮游生物进行了调查,采用生态系统健康指数(EHI)法和营养状态指数(TSI)法对该水库的生态系统健康状态进行定量的综合评价.结果表明:2007年7月~2008年5月,丹江口水库整体处于中营养状态,健康状态中等,健康状态总趋势是丹江库区>取水口>汉江库区>五青入库区;各库区生态系统健康状态存在季节性差异,丹江库区、取水口两库区全年为中等,汉江库区在夏季为较差,其它季节中等,五青入库区在冬季最差,其它季节较差.此外,对两种评价方法进行了比较,表明丹江口水库属于响应型生态系统,生态系统健康指数(EHI)适用于丹江口水库生态系统健康的评价.  相似文献   

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Recent emphasis on a holistic view of natural systems and their management is associated with a growing appreciation of the role of human values in these systems. In the past, resource management has been perceived as a dichotomy between extraction (harvest) and nonconsumptive use, but this appears to be an oversimplified view of natural-cultural systems. The recreational fishery for Yellowstone cutthroat trout ( Oncorhynchus clarki bouvieri ) in Yellowstone National Park is an example of the effects of management on a natural-cultural system. Although angler harvest has been drastically reduced or prohibited, the recreational value of Yellowstone cutthroat trout estimated by angling factors (such as landing rate or size) ranks above that of all other sport species in Yellowstone National Park. To maintain an indigenous fishery resource of this quality with hatchery propagation is not economically or technically feasible. Nonconsumptive uses of the Yellowstone cutthroat trout including fish-watching and intangible values, such as existence demand, provide additional support for protection of wild Yellowstone cutthroat trout populations. A management strategy that reduces resource extraction has provided a means to sustain a quality recreational fishery while enhancing values associated with the protection of natural systems.  相似文献   

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水生态模拟系统是用于高层次化学品生态风险评估的测试模型,目前在国外已经广泛用于工业化学品、农药、兽药、重金属等单一化学物质和复杂混合物的生态风险评估研究,而我国的相关研究比较匮乏。随着我国化学品风险评估体系的完善,水生态模拟系统测试必将作为作为单一生物毒性测试的有效补充。在此背景下,简述了水生态模拟系统的分类、研究方法和结果外推方法;从单一化学物质暴露作用下的生态危害评估、多种化学物质联合暴露作用下的生态危害评估以及目标化学物质的归趋分析三个方面阐述了水生态模拟系统在国内外化学品风险评估科学研究中的应用,对比了水生态模拟系统和单一物种毒性测试结果和基于两种测试数据的生态危害评估结果。与此同时,分析了水生态模拟系统在国内外化学品环境管理中的应用情况。在此基础上,对我国发展水生态模拟系统所存在的问题及解决方案提出了建议。  相似文献   

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广西大化县属于典型的岩溶地区,具有岩溶区特有的脆弱生态环境系统,石漠化面积较大,生态系统稳定性差.以大化县16个乡镇为评价对象,合理选取9项岩溶地区生态环境脆弱性影响因子,并建立生态环境脆弱性评价指标体系,采用主成分分析方法确定各指标的权重和模糊综合评价分析方法进行生态环境脆弱性评价,从而为大化县的岩溶生态系统的恢复和重建、土地利用结构的优化提供参考资料.结果表明,有4个中度脆弱乡镇,8个轻度脆弱乡镇,4个潜在脆弱乡镇.图1,表5,参16.  相似文献   

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