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141.
Walter J. Hamming Robert D. Macphee James R. Taylor 《Journal of the Air & Waste Management Association (1995)》2013,63(1):7-16
Sampling for nitrogen and sulfur dioxides was initiated at several National Air Sampling Network stations in 1959 using a sampler developed for that purpose. In 1961 the Gas Sampling Network was expanded to its maximum of 49 stations. Sampling equipment and collecting solutions are supplied and chemical analyses performed by the network laboratories. Sampling and analysis procedures are described briefly. Average and maximum 24-hour concentrations of nitrogen dioxide and sulfur dioxide observed at 48 stations during 1961-1963 are presented. 相似文献
142.
O. C. Taylor 《Journal of the Air & Waste Management Association (1995)》2013,63(5):347-355
Peroxyacyl nitrates are a family of compounds which result from photochemical reactions between contaminants released to the atmosphere by combustion of organic fuels. Peroxyacetyl nitrate (PAN) is the most abundant member of this family and is responsible for serious plant injury in some polluted areas. Plant injury has been recognized in at least 19 states and several foreign countries but economic loss has caused greatest concern in California. Characteristically, injury from PAN appears as glazing or bronzing of the lower leaf surface but the symptom syndrome may also include tissue collapse, chlorosis, and leaf drop. PAN inhibits activity of several enzyme systems by attacking the sulfhydryl group when enzyme extracts are fumigated in vitro, PAN may produce visible symptoms when sensitive plants are exposed for 4 hours to about 14 ppb. Other chemical members of the family are more toxic than PAN. Concentrations of 20 to 30 ppb PAN occur frequently at Riverside, Calif, and a maximum peak of 58 ppb was measured for one 2-hour period. Peaks as high as 54 ppb were reported at Salt Lake City, and 210 ppb at Los Angeles, Calif. 相似文献
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148.
Quantifying species recovery and conservation success to develop an IUCN Green List of Species 下载免费PDF全文
H. Resit Akçakaya Elizabeth L. Bennett Thomas M. Brooks Molly K. Grace Anna Heath Simon Hedges Craig Hilton‐Taylor Michael Hoffmann David A. Keith Barney Long David P. Mallon Erik Meijaard E.J. Milner‐Gulland Ana S.L. Rodrigues Jon Paul Rodriguez P.J. Stephenson Simon N. Stuart Richard P. Young 《Conservation biology》2018,32(5):1128-1138
Stopping declines in biodiversity is critically important, but it is only a first step toward achieving more ambitious conservation goals. The absence of an objective and practical definition of species recovery that is applicable across taxonomic groups leads to inconsistent targets in recovery plans and frustrates reporting and maximization of conservation impact. We devised a framework for comprehensively assessing species recovery and conservation success. We propose a definition of a fully recovered species that emphasizes viability, ecological functionality, and representation; and use counterfactual approaches to quantify degree of recovery. This allowed us to calculate a set of 4 conservation metrics that demonstrate impacts of conservation efforts to date (conservation legacy); identify dependence of a species on conservation actions (conservation dependence); quantify expected gains resulting from conservation action in the medium term (conservation gain); and specify requirements to achieve maximum plausible recovery over the long term (recovery potential). These metrics can incentivize the establishment and achievement of ambitious conservation targets. We illustrate their use by applying the framework to a vertebrate, an invertebrate, and a woody and an herbaceous plant. Our approach is a preliminary framework for an International Union for Conservation of Nature (IUCN) Green List of Species, which was mandated by a resolution of IUCN members in 2012. Although there are several challenges in applying our proposed framework to a wide range of species, we believe its further development, implementation, and integration with the IUCN Red List of Threatened Species will help catalyze a positive and ambitious vision for conservation that will drive sustained conservation action. 相似文献
149.
Scot D. Anderson Taylor K. Chapple Salvador J. Jorgensen A. Peter Klimley Barbara A. Block 《Marine Biology》2011,158(6):1233-1237
Mark-recapture techniques can be used to estimate white shark (Carcharodon carcharias) population abundance. These frameworks are based on assumptions that marks are conserved and animals are present at the
sampling location over the entire duration of the study. Though these assumptions have been validated across short-time scales
for white sharks, long-term studies of population trends are dependent on these assumptions being valid across longer periods.
We use 22 years of photographic data from aggregation sites in central California to support the use of dorsal fin morphology
as long-term individual identifiers. We identified five individuals over 16–22 years, which support the use of dorsal fins
as long-time individual identifiers, illustrate strong yearly site fidelity to coastal aggregation sites across extended time
periods (decades), and provide the first empirical validation of white shark longevity >22 years. These findings support the
use of fin morphology in mark-recapture frameworks for white sharks. 相似文献
150.
Charles H. Peterson Stephen R. Fegley Christine M. Voss Sara R. Marschhauser Beth M. VanDusen 《Marine Biology》2013,160(3):629-640
Protecting eggs from predators is common practice in sea turtle conservation, but routine protection of hatchlings is not. Of 42 loggerhead hatchlings observed emerging from 10 nests on undeveloped Onslow Beach, North Carolina, 24 % were preyed on by ghost crabs. In experimental trials, ghost crabs similarly threatened and captured neonate freshwater sliders, supporting their substitution as proxy for threatened and endangered sea turtle hatchlings in field experiments testing density dependence. Exploiting natural long-shore variation in ghost crab density, we show that a 2.6-fold higher ghost crab density resulted in 5 times more nocturnal threat encounters with sliders and 3.4 times more slider captures. Sliders released in simulated group emergences experienced lower per capita capture risk by ghost crabs than solitary sliders, implying predator dilution. Non-independence of egg and hatchling depredation motivates consideration of merging sea turtle egg and hatchling stages when modeling and managing food web interactions. 相似文献