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61.
苔藓植物资源丰富、种类繁多、分布广泛,是一类以孢子繁殖,由水生向陆生过渡的高等植物。苔藓植物的结构相对简单,对环境变化的反应较为敏感,被广泛应用为环境污染的指示植物。苔藓植物生长与所处的环境有关,而它的生长对土壤结皮形成、水土保持、生态小环境改善等方面又发挥着重要的促进作用。综述了苔藓植物的资源分布、苔藓植物对环境污染的响应、苔藓植物的生态效应等方面的研究进展,但是目前的研究领域及其研究角度还存在着各自的不足。随着经济建设快速发展,世界各地大量的矿山开采、水电开发等工程建设对土地、自然环境的破坏日益严重,非农业建设以及农产品需求不断增加造成了农田的生态结构与功能发生着不断变化。针对各地经济社会发展以及城乡建设现状,积极开展工程建设领域以及农田生态系统苔藓植物的生态环境效应研究是今后值得十分重视的研究方向。  相似文献   
62.
In order to resolve the spatial component of the design of a water quality monitoring network, a methodology has been developed to identify the critical sampling locations within a watershed. This methodology, called Critical Sampling Points (CSP), focuses on the contaminant total phosphorus (TP), and is applicable to small, predominantly agricultural-forested watersheds. The CSP methodology was translated into a model, called Water Quality Monitoring Station Analysis (WQMSA). It incorporates a geographic information system (GIS) for spatial analysis and data manipulation purposes, a hydrologic/water quality simulation model for estimating TP loads, and an artificial intelligence technology for improved input data representation. The model input data include a number of hydrologic, topographic, soils, vegetative, and land use factors. The model also includes an economic and logistics component. The validity of the CSP methodology was tested on a small experimental Pennsylvanian watershed, for which TP data from a number of single storm events were available for various sampling points within the watershed. A comparison of the ratios of observed to predicted TP loads between sampling points revealed that the model's results were promising.  相似文献   
63.
The U.S. Environmental Protection Agency (EPA) is in the process of designing a national network to monitor hazardous air pollutants (HAPs), also known as air toxics. The purposes of the expanded monitoring are to (1) characterize ambient concentrations in representative areas; (2) provide data to support and evaluate dispersion and receptor models; and (3) establish trends and evaluate the effectiveness of HAP emission reduction strategies. Existing air toxics data, in the form of an archive compiled by EPA's Office of Air Quality Planning and Standards (OAQPS), are used in this paper to examine the relationship between estimated annual average (AA) HAP concentrations and their associated variability. The goal is to assess the accuracy, or bias and precision, with which the AA can be estimated as a function of ambient concentration levels and sampling frequency. The results suggest that, for several air toxics, a sampling schedule of 1 in 3 days (1:3) or 1:6 days maybe appropriate for meeting some of the general objectives of the national network, with the more intense sampling rate being recommended for areas expected to exhibit relatively high ambient levels.  相似文献   
64.
Drought is a part of the normal climate variability and the life and livelihoods of the Western United States. However, drought can also be a high impact or extreme event in some cases, such as the exceptional 2002 drought that had deleterious impacts across the Western United States. Studies of long-term climate variability along with climate change projections indicate that the Western United States should expect much more severe and extended drought episodes than experienced over the last century when most modern water law and policies were developed, such as the 1922 Colorado River Compact. This paper will discuss research examining regional socio-natural climate vulnerability and adaptive response capacities to the 2002 drought in the Yampa–White Basins region of Colorado across sectors and will demonstrate how a bottom-up or “toad’s eye” approach to understanding drought is paramount to complement top-down, instrumental data-driven analyses of drought. The results of empirical observations through interviews and participant observation in combination with analysis of drought indicators will be presented. Implications for adaptation research and planning for climate variability and change will be discussed.  相似文献   
65.
This paper examines the factors shaping non-governmental organization (NGO) messaging decisions on how meat consumption should be altered in light of climate change. In particular, we sought to understand the relative absence of messages promoting meat-free diets and the decision of some NGOs to pair meat reduction messages with messages encouraging consumers to switch to meat from ruminant grass-fed animals. Interviews were conducted with 27 staff members from environmental, food-focused, and animal protection NGOs from the USA, Canada, and Sweden. While strategic considerations consistently led to the use of modest messages for meat reduction, NGO missions were also key to shaping the specifics of messaging goals. The relatively low personal comfort levels that some NGO staffers held toward meat-free diets also led to the use of more modest requests for meat reduction. Findings highlight the complex nature of the factors underlying the environmental communication messages of NGOs.  相似文献   
66.
Citizen science has generated a growing interest among scientists and community groups, and citizen science programs have been created specifically for conservation. We examined collaborative science, a highly interactive form of citizen science, which we developed within a theoretically informed framework. In this essay, we focused on 2 aspects of our framework: social learning and adaptive management. Social learning, in contrast to individual‐based learning, stresses collaborative and generative insight making and is well‐suited for adaptive management. Adaptive‐management integrates feedback loops that are informed by what is learned and is guided by iterative decision making. Participants engaged in citizen science are able to add to what they are learning through primary data collection, which can result in the real‐time information that is often necessary for conservation. Our work is particularly timely because research publications consistently report a lack of established frameworks and evaluation plans to address the extent of conservation outcomes in citizen science. To illustrate how our framework supports conservation through citizen science, we examined how 2 programs enacted our collaborative science framework. Further, we inspected preliminary conservation outcomes of our case‐study programs. These programs, despite their recent implementation, are demonstrating promise with regard to positive conservation outcomes. To date, they are independently earning funds to support research, earning buy‐in from local partners to engage in experimentation, and, in the absence of leading scientists, are collecting data to test ideas. We argue that this success is due to citizen scientists being organized around local issues and engaging in iterative, collaborative, and adaptive learning.  相似文献   
67.
The freshwater resources of small islands are particularly vulnerable to the impacts of climate change and human stressors due to their limited extent and adaptive capacity. A water security approach is useful for effective management of the water resources; however, understanding risk to water security is critical in order to effectively plan and adapt to future changes. Currently available assessment tools generally do not incorporate risk and are not suitable for application on small islands, where the hydrogeological setting has unique vulnerabilities. The aim of this work is to provide a framework to characterize risk to water security for small islands. The risk assessment was developed using Andros Island, the Bahamas, as a case study area. Numerical modelling characterizes the response of the water system to potential future stressors related to climate change and human development, the results of which are integrated into the assessment framework. Based on risk assessment principles, indicators are determined for susceptibility, hazard threat, vulnerability and loss, in order to define the risk to water security. The resulting indicators are presented in geospatial maps that rank areas of risk to water security. These maps were provided to local water managers and policy-makers in the Bahamas as a tool to identify high-risk areas for near-term action and to inform long-term planning. The maps have also been used as a platform to engage local residents and raise awareness about the impact climate change and land-use activities may have on water security.  相似文献   
68.
69.
The occurrence and estimated concentration of twenty illicit and therapeutic pharmaceuticals and metabolites in surface waters influenced by wastewater treatment plant (WWTP) discharge and in wastewater effluents in Nebraska were determined using Polar Organic Chemical Integrative Samplers (POCIS). Samplers were installed in rivers upstream and downstream of treated WWTP discharge at four sites and in a discharge canal at a fifth location. Based on differences in estimated concentrations determined from pharmaceuticals recovered from POCIS, WWTP effluent was found to be a significant source of pharmaceutical loading to the receiving waters. Effluents from WWTPs with trickling filters or trickling filters in parallel with activated sludge resulted in the highest observed in-stream pharmaceutical concentrations. Azithromycin, caffeine, 1,7-dimethylzanthine, carbamazepine, cotinine, DEET, diphenhydramine, and sulfamethazine were detected at all locations. Methamphetamine, an illicit pharmaceutical, was detected at all but one of the sampling locations, representing only the second report of methamphetamine detected in WWTP effluent and in streams impacted by WWTP effluent.  相似文献   
70.
We collected female greater scaup (Aythya marila) on the Yukon-Kuskokwim Delta, Alaska during two breeding seasons to determine if concentrations of 18 trace elements in livers and eggs were elevated and if hepatic concentrations correlated with body condition or affected reproductive status. Fifty-six percent, 5%, and 42% of females, respectively, had elevated hepatic cadmium (Cd: >3 μg g−1 dry weight [dw]), mercury (Hg: >3 μg g−1 dw), and selenium (Se: >10 μg g−1 dw). Somatic protein and lipid reserves were not correlated with hepatic Cd or Hg, but there was a weak negative correlation between protein and Se. Hepatic Cd, Hg, and Se were similar in females that had and had not initiated egg production. In a sample of six eggs, 33% and 100%, respectively, contained Se and Hg, but concentrations were below embryotoxicity thresholds. We conclude that trace element concentrations documented likely were not adversely impacting this study population.  相似文献   
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