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231.
232.
Abstract: Some conservationists argue for a focused effort to protect the most critically endangered species, and others suggest a large‐scale endeavor to safeguard common species across large areas. Similar arguments are applicable to the distribution of scientific effort among species. Should conservation scientists focus research efforts on threatened species, common species, or do all species deserve equal attention? We assessed the scientific equity among 1909 mammals, birds, reptiles, and amphibians of southern Africa by relating the number of papers written about each species to their status on the International Union for Conservation of Nature Red List. Threatened large mammals and reptiles had more papers written about them than their nonthreatened counterparts, whereas threatened small mammals and amphibians received less attention than nonthreatened species. Threatened birds received an intermediate amount of attention in the scientific literature. Thus, threat status appears to drive scientific effort among some animal groups, whereas other factors (e.g., pest management and commercial interest) appear to dictate scientific investment in particular species of other groups. Furthermore, the scientific investment per species differed greatly between groups—the mean number of papers per threatened large mammal eclipsed that of threatened reptiles, birds, small mammals, and amphibians by 2.6‐, 15‐, 216‐, and more than 500‐fold, respectively. Thus, in the eyes of science, all species are not created equal. A few species commanded a great proportion of scientific attention, whereas for many species information that might inform conservation is virtually nonexistent. 相似文献
233.
Craig H. Bullock David A. Elston Neil A. Chalmers 《Journal of environmental management》1998,52(4):335-351
Stalking (deer hunting) is an important land use and activity in the Scottish Highlands, and deer managers have traditionally maintained large numbers of female deer in order to supply a guaranteed number of stags for stalking. Unfortunately, grazing by large numbers of deer conflicts with environmental objectives that are seeking to improve upland habitats and increase the area of native Caledonian Pine forest. This study uses a multi-attribute choice experimental approach to quantify the various characteristics of the stalking experience to determine the value that amateur stalkers attach to the stag numbers, the landscape and other attibutes. Unlike previous applications of stated preference, a large proportion (one-third) of a full factorial design is used to present stalkers with different alternative stalking packages within a postal survey. The results indicate a way forward that could be agreeable to both deer managers and conservationists. 相似文献
234.
Elizabeth L. White 《Journal of the American Water Resources Association》1976,12(2):351-370
ABSTRACT. The interrelationships between the runoff characteristics of watersheds (expressed as the mean annual flood), standard basin parameters (area, drainage properties, and relief), and the parameters which describe the solutional modification of the basins (carbonate rock fractions, sinkhole development, and measures of internal drainage) were used to group 62 carbonate watersheds. Simple binary correlations were obtained by direct plotting of the data. This was followed by multivariate analyses: factor and cluster analyses. Following the cluster analysis, which separated the basins into three groups, the variance within each group was examined again by binary correlations and by factor analysis. Prediction equations for those basins underlain by dolomite rock [QBAR = 12.4 TOT1.01] and for those basins underlain by carbonate rock with very little surface expression [QBAR = 43.5 TOT0.87] were proposed. Basins underlain by karstic limestone had a large amount of variance within the data set; therefore no prediction equation could be obtained. (QBAR = mean annual flood, cfs; TOT = total length of all blue lines shown on topographic maps, miles.) 相似文献
235.
K. R. Rushton L. M. Tomlinson 《Journal of the American Water Resources Association》1981,17(3):406-413
The simulation of the conjunctive use of a surface reservoir and a limestone aquifer is described. The potential yields from each of the sources are of the same order. An important feature of the aquifer is that if the pumpage is reduced, much of the excess water is lost through springs. Five different operating policies are considered which determine whether pumpage should be taken from the reservoir or aquifer. The total safe yields for the historic period 1961–1977 are estimated for each policy and their relative advantages and disadvantages are discussed. The simulation is also carried out for 100 years of generated data to discover the long term consequences. 相似文献
236.
大巴山地处川、陕、渝的接合部,大气质量较好;由于特殊的地质构造,这里矿产资源较丰富;生物资源极其丰富,局部保存有原始森林,具有重要的科研、经济价值;旅游资源也极其丰富,是开展生态旅游和红色旅游的极好地区. 相似文献
237.
近年来,我国沿海地区越来越频繁的赤潮对水域环境与海水养殖业等造成了严重破坏。本文从赤潮发生的条件入手,分析了赤潮的预测方法,并提出了相应的对策。 相似文献
238.
P. J. Wigington M. R. Church T. C. Strickland K. N. Eshleman J. Van Sickle 《Journal of the American Water Resources Association》1998,34(5):1035-1049
ABSTRACT: During an autumn runoff event we sampled 48 streams with predominantly forested watersheds and igneous bedrock in the Oregon Coast Range. The streams had acid neutralizing capacities (ANC) > 90 μeq/L and pH > 6.4. Streamwater Na +, Ca2 +, and Mg2 + concentrations were greater than K + concentrations. Anion concentrations generally followed the order of Cl- > NO3- > SO42-. Chloride and Na + concentrations were highest in samples collected in streams near the Pacific Ocean and decreased markedly as distance from the coast increased. Sea salt exerted no discernible influence on stream water acid-base status during the sampling period. Nitrate concentrations in the study streams were remarkably variable, ranging from below detection to 172 μeq/L. We hypothesize that forest vegetation is the primary control of spatial variability of the NO3- concentrations in Oregon Coast Range streams. We believe that symbiotic N fixation by red alder in pure or mixed stands is the primary source of N to forested watersheds in the Oregon Coast Range. 相似文献
239.
R. Lynn Taylor Paul W. Adams 《Journal of the American Water Resources Association》1986,22(4):629-635
ABSTRACT: Streamside red alder (Alnus rubra Bong.) stands are common in western Oregon, and they have been suspected of causing water quality problems in domestic supplies during autumn leaf fall. Studies in the Seaside municipal watershed showed potential water quality effects (particularly increased color) from alder leaves, but stream sampling during 1981–82 revealed no chronic problems. The few observed short-term increases in water color occurred near the onset of storm flows, which suggested a flushing of organic matter storage sites. An extended period of unusually low flows and high leaf fall are probably necessary to produce significant water quality problems in this stream system. Laboratory leaching of alder leaves in filtered stream water indicated a fairly constant release of colored organic matter over time, and running water leached this matter more efficiently than still water. Water color increased linearly with increasing leaf mass added to still water, and for a given leaf mass there appeared to be a limit to the amount of colored matter that could be removed in the first 48 hours of leaching. Other laboratory tests showed that ultraviolet absorbance (254 mm) may provide a reasonable estimate of dissolved organic carbon concentrations in systems dominated by alder leaf inputs. 相似文献
240.
褐菖鮋(Sebastiscusmarmoratus)金属硫蛋白的分离提纯及免疫测定 总被引:3,自引:0,他引:3
通过Sephadex G-75凝胶过滤和DEAE-Sepharose CL-6B离子交换柱层析,从褐菖You肝脏分离金属硫蛋白。经氨基酸组成分析表明:褐菖You金属硫蛋白不含环状氨基酸,半胱氨酸含量达35%,估算分子量为6700道尔顿。等电聚焦显示两条区带,PI分别为4.0和4.2。金属硫蛋白经与牛血蛋白交联对兔进行免疫,兔抗血清用ProteinA亲和纯化并标记上辣根过氧化物酶,利用酶联免疫吸附测 相似文献