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951.
952.
Derek B. Booth James R. Karr Sally Schauman Christopher P. Konrad Sarah A. Morley Marit G. Larson Stephen J. Burges 《Journal of the American Water Resources Association》2004,40(5):1351-1364
ABSTRACT: Successful stream rehabilitation requires a shift from narrow analysis and management to integrated understanding of the links between human actions and changing river health. At study sites in the Puget Sound lowlands of western Washington State, landscape, hydrological, and biological conditions were evaluated for streams flowing through watersheds with varying levels of urban development. At all spatial scales, stream biological condition measured by the benthic index of biological integrity (B‐IBI) declined as impervious area increased. Impervious area alone, however, is a flawed surrogate of river health. Hydrologic metrics that reflect chronic altered streamflows, for example, provide a direct mechanistic link between the changes associated with urban development and declines in stream biological condition. These measures provide a more sensitive understanding of stream basin response to urban development than do treatment of each increment of impervious area equally. Land use in residential backyards adjacent to streams also heavily influences stream condition. Successful stream rehabilitation thus requires coordinated diagnosis of the causes of degradation and integrative management to treat the range of ecological stressors within each urban area, and it depends on remedies appropriate at scales from backyards to regional storm water systems. 相似文献
953.
作为国家级风景区的云台山蕴藏着丰富的生物资源,本文从生物资源的可持续开发和经济学角度出发,对合理利用云台山的生物资源作了初步探讨。 相似文献
954.
辛醇生产废水处理技术 总被引:2,自引:0,他引:2
对国内外辛醇生产废水的处理方法作了介绍,并对较先进的酸化萃取法和厌氧生化-好氧生化-碳黑吸附法作了详细分析。 相似文献
955.
国内甲醇废水处理技术应用现状 总被引:12,自引:2,他引:10
介绍了汽化法、厌氧生物处理法和好氧化生物处理法在国内甲醇废水处理中的应用情况,存在的问题,并提出了一些改进建议。 相似文献
956.
Spermophilus townsendii ) prey. These changes could occur directly or as a result of changes in the vegetation available as food and cover for the
ground squirrels. We assessed the effects of long-term tracking by armored vehicles by comparing 9-ha areas in sagebrush (Artemisia tridentata) -dominated shrubsteppe and bluegrass (Poa secunda) -dominated grasslands subjected to low-intensity tracking for ∼50 years with others that had not been tracked. We did not
detect any effect on ground squirrel population dynamics associated with long-term tracking. Although densities of adults
and juveniles tended to be higher in the areas exposed to such tracking, we attribute this difference to other factors that
varied spatially. To determine short-term (two-year) effects, we experimentally tracked two sagebrush and two grassland sites
with an M-1 tank after animals had begun their inactive season. In the following two active seasons we monitored squirrel
demography and behavior and vegetative characteristics on the experimentally tracked sites and compared the results with control
sites. Although we experimentally tracked ∼33% of the surface of each of four sites where ground squirrel densities were assessed,
the tracking had a detectable effect only on some herbaceous perennials and did not influence ground squirrel densities or
behavior significantly during the subsequent two active seasons. We conclude that tracking after the start of the inactive
season is likely to influence ground squirrel demography or behavior only if vegetation cover is substantially changed by
decreasing coverage of preferred food plants or increasing the coverage of annual grasses and forbs that are succulent for
only a short time each year. 相似文献
957.
本文调查研究了日本弓背蚁的群体结构和生物学特性,并初步探讨了日本弓背蚁的营养价值及其开发利用对策. 相似文献
958.
胜利油田位于我国黄河三角洲地区,潜水位高,水的矿化度大。生态环境恶劣,对植物尤其对木本植物的生长不利,整个地区生长的多是抗盐碱能力强的草本植物。针对油田的特殊环境条件,综合有关资料,介绍了以沙枣为代表的植物特性,特别强调了其抗盐碱、降低土壤矿化度和潜水位、增加土壤有机质和引起植被变化的特性。指出黄河三角洲也有些土质较好的、适于作物和木本植物生长的地区,改良盐碱地可以以这些地区为基点,放射性地向外逐步试验沙枣的种植,以探索改善生态环境的途径。努力做到边发展经济,边改善环境,达到经济效益、社会效益和环境效益三统一。 相似文献
959.
文中介绍了国外用土壤空气抽取法和堆肥法清除土壤中有机溶剂、芳香烃类和石油污染物的技术及其应用。这两种方法单独使用均可成功地治理有害废弃物。实践证明,将这两种技术串联使用可更有效地处理土壤中污染物及加速生物降解过程。根据现场特点,利用多种治理技术综合治理土壤污染物是治理污染物的发展方向。 相似文献
960.
Robert Coats Laurel Collins Joan Florsheim Darrell Kaufman 《Environmental management》1985,9(1):35-48
A study on sediment transport and channel change was conducted on Zayante Creek and the lower San Lorenzo River in Santa Cruz County, California. A rainstorm with a recurrence interval locally in excess of 150 years occurred during the study year, 1982 WY. Stream surveys indicated that significant aggradation occurred during and after the peak flood. Upper study reaches were substantially recovered after high flows of early April, but the lower study reaches still had significant filling of pools and burial of riffles by sand. Increases in width-depth ratio were minor and localized in upper reaches, but were significant in lower reaches. Large inputs of sand, primarily from landsliding, altered the sediment transport regime. A higher proportion of the bedload is now transported by lower flows than before the January event. Roads and sand quarries contributed significantly to sediment input to the stream. A proposed dam may alter the sediment transport regime of Zayante Creek. Mitigating the effects of this dam on downstream fish habitat may require occasional bankfull discharges. 相似文献