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91.
Abstract:  The rainforests of the Amazon basin are being cut by humans at a rate >20,000 km2/year, leading to smaller and more isolated patches of forest, with remaining fragments often in the range of 1–100 ha. We analyzed samples of understory birds collected over 20 years from a standardized mist-netting program in 1– to 100-ha rainforest fragments in a dynamic Amazonian landscape near Manaus, Brazil. Across bird guilds, the condition of second growth immediately surrounding fragments was often as important as fragment size or local forest cover in explaining variation in abundance. Some fragments surrounded by 100 m of open pasture showed reductions in insectivorous bird abundance of over 95%, even in landscapes dominated by continuous forest and old second growth. These extreme reductions may be typical throughout Amazonia in small (≤10 ha), isolated fragments of rainforest. Abundance for some guilds returned to preisolation levels in 10- and 100-ha fragments connected to continuous forest by 20-year-old second growth. Our results show that the consequences of Amazonian forest loss cannot be accurately described without explicit consideration of vegetation dynamics in matrix habitat. Any dichotomous classification of the landscape into "forest" and "nonforest" misses essential information about the matrix.  相似文献   
92.
A Mesofilter Conservation Strategy to Complement Fine and Coarse Filters   总被引:5,自引:1,他引:5  
Abstract:  Setting aside entire ecosystems in reserves is an efficient way to maintain biodiversity because large numbers of species are protected, but ecosystem conservation constitutes a coarse filter that does not address some species. A complementary, fine-filter approach is also required to provide tailored management for some species (e.g., those subject to direct exploitation). Mesofilter conservation is another complementary approach that focuses on conserving critical elements of ecosystems that are important to many species, especially those likely to be overlooked by fine-filter approaches, such as invertebrates, fungi, and nonvascular plants. Critical elements include structures such as logs, snags, pools, springs, streams, reefs, and hedgerows, and processes such as fires and floods. Mesofilter conservation is particularly appropriate for seminatural ecosystems that are managed for both biodiversity and commodity production (e.g., forests managed for timber, grasslands managed for livestock forage, and aquatic ecosystems managed for fisheries) and is relevant to managing some agricultural and urban environments for biodiversity.  相似文献   
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94.
News accounts both reflect and influence public opinion through their noted ‘agenda-setting’ capability. We examined newspaper articles in Australia’s The Sydney Morning Herald from 1843 to 2011 to observe the evolution of media coverage on water issues related to water resources management. The results showed that water supply-related articles have dominated the reporting of water issues since 1843. This emphasis is reflected in the institutions involved and their related policy/management initiatives, as well as the themes of the articles. Extreme events such as flooding and drought have punctuated the historical record of reports on water issues. An economic development-driven tone was overwhelmingly predominant in newspaper articles (85 % of the total); however, there has been a marked decline in the importance of development-driven tone relative to environmental-sustainability oriented tone of articles since 1994. People from academia and NGOs were rarely quoted. Inclusion of wider range stakeholders should be considered as a strategic break-through and natural events should be considered as an “opportunity” to change public opinion on water issues for environmental sustainability.  相似文献   
95.
The air pollution potential of any area is directly related to its population and economic development. In New York State, this pollution potential ranges from that existing in the sparsely inhabited recreational zones to that prevailing in the densely populated and/or heavily industrialized areas. No one set of air quality standards or objectives can be developed which can reasonably be applied on a statewide basis. A classifications-air quality objectives system has been adopted by the State Air Pollution Control Board for application in New York State. In accordance with this system, specific areas can be classified in one of 16 categories. Air quality objectives, in keeping with each classification, are designed to protect health and to promote the maximum comfort and enjoyment and use of property consistent with the needs of the area concerned. The system was developed by the staff with the assistance of a council of technical advisors. Units of measurement related to the most important effect of specific contaminants are utilized. Methods of sampling and analysis are specified. The details of the classifications-objectives system, the place of the system in the state’s air resource management plan, the manner in which each segment of the state after study will be classified, and how attainment will be evaluated are described.  相似文献   
96.
This paper briefly reviews the historical development of air pollution training activities in the U. S. It describes the various types of training programs currently available, such as short courses, specialized programs, and university training at the graduate level. The level of financial support and the number of individuals enrolled in these programs are discussed. The paper concludes with an outline of future needs in terms of changes in existing training programs, extension into new areas, and the critical problem of recruitment of qualified candidates for training.  相似文献   
97.
98.
PCBs (as Aroclor concentrations) have been extensively examined in fish along the Hudson River, but other xenobiotic chemicals in fish have had limited assessment. This study determined concentrations and congener distributions of polybrominated diphenyl ethers (PBDEs), polybrominated and polychlorinated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs and PCDD/Fs), and polychlorinated biphenyls (PCBs) in smallmouth bass and striped bass taken from a 385 km reach of the Hudson River. Concentrations of PBDEs and PCBs in smallmouth bass, and PCBs in striped bass, were positively related to human uses of the compounds in the basin. Generally low levels of PCDD/Fs were found. One striped bass, however, contained elevated 2,3,7,8-TCDD, indicating exposure to a known source in the adjacent Newark Bay-Passaic River basin. PBDDs were generally below detection. PBDFs were present in four of 18 smallmouth bass, but were not detected in striped bass. Dioxin-like PCBs contribute most to 2,3,7,8-TCDD toxic equivalents in 29 of 30 samples.  相似文献   
99.
Why Economics Matters for Endangered Species Protection   总被引:3,自引:0,他引:3  
Abstract: We offer three reasons why economics matters more to species protection than many people think and what this implies for the ongoing debate over the reauthorization of the Endangered Species Act of 1973. Economics matters because (1) human behavior generally, and economic parameters in particular, help determine the degree of risk to a species; (2) in a world of scarce resources, the opportunity cost of species protection—the costs of reduced resources for other worthwhile causes—must be taken into account in decision making; and (3) economic incentives are critical in shaping human behavior, and consequently the recovery of species. Endangered species protection that explicitly addresses these basic principles can avoid wasting valuable resources that yield no gain in species protection.  相似文献   
100.
A 4year study surveyed 131 lakes across New York State beginning in 2003 to improve our understanding of mercury and gather information from previously untested waters. Our study focused on largemouth and smallmouth bass, walleye and yellow perch, common piscivorous fish shown to accumulate high mercury concentrations and species important to local fisheries. Fish from Adirondack and Catskill Forest Preserve lakes generally had higher mercury concentrations than those from lakes in other areas of the state. Variability between nearby individual lakes was observed, and could be due to differences in water chemistry, lake productivity or the abundance of wetlands in the watershed. We found the following factors impact mercury bioaccumulation: fish length, lake pH, specific conductivity, chlorophyll a, mercury concentration in the water, presence of an outlet dam and amount of contiguous wetlands.  相似文献   
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