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611.
612.
Amphibian Breeding Distribution in an Urbanized Landscape 总被引:5,自引:0,他引:5
Abstract: Amphibians commonly use wetlands for breeding habitat, and given the concern about their ongoing global declines, the effects of urbanization on the breeding distribution of amphibians need to be quantified. Thus, we conducted a survey of the larval amphibian community in central Pennsylvania (U.S.A.) wetlands along an urbanization gradient. Wetlands in urban areas had less surrounding forest and wetlands and greater road density than rural wetlands. Urbanization was also associated with increases in hydroperiod (i.e., wetland permanency) and the presence of fish predators. Moreover, urban wetlands had lower larval amphibian species richness than rural wetlands. This decrease in richness was attributable to a decrease in occurrence of wood frogs ( Rana sylvatica ) and ambystomatid salamanders ( Ambystoma maculatum and A. jeffersonianum ) in urban sites. Wood frogs and ambystomatid salamanders were positively associated with the amount of forest surrounding sites and negatively associated with hydroperiod. As a result, we hypothesize that these species are sensitive to the effects of urban development. The remaining species in this study appear fairly resilient to the effects of urbanization. These data demonstrate the importance of quantifying both local and landscape attributes when describing the factors that limit the breeding distribution of amphibians. We recommend that to preserve amphibian biodiversity in urbanized landscapes, it is best to focus on regional diversity, which protects a variety of sites that encompass various hydroperiods, have adequate buffer habitat, and are connected by dispersal routes. 相似文献
613.
基质是潜流式人工湿地污水处理系统的重要组成部分,直接影响到系统的处理效果.本文研究了由沸石、页岩陶粒和碎石3种不同基质构建的潜流式人工湿地对磷的去除效果.结果表明,在设计水力停留时间3 d,连续进出水情况下,碎石单元对磷的去除效果最好,页岩陶粒单元次之,沸石单元效果最差,平均去除率分别为95%、60%和35%.在潜流式人工湿地污水处理系统运行初期观察到磷释放现象,沸石单元最为明显.进水磷浓度较低时,磷的去除率随浓度升高而升高,当正磷、总磷浓度分别升高到2.4~2.5和3.1~3.3 mg/L时,正磷、总磷的去除率开始迅速下降. 相似文献
614.
Mirady Sebastiani Sara Elena González María Mercedes Castillo Pablo Alvizu María Albertina Oliveira Jorge Pérez Antonio Quilici Martín Rada María Carolina Yáber Miguel Lentino 《Environmental management》1994,18(5):647-661
In Venezuela, large-scale shrimp farming began in the 1980s. By 1987, the Ministry of Environment and Natural Resources (MARNR)
had received 14 proposals for approval. A developer illegally started the construction of ponds at the Píritu Lagoon in the
State of Anzoátegui before the authorization process was completed. This action triggered a land-use conflict. This study
identifies the causes for public protest and determines the consequences of this conflict for land-use management. The results
show that public protest was based on the impacts of the partial construction of ponds. These impacts were related to direct
removal of wetlands, interruption of natural patterns of surface flows, and alteration of feeding grounds of some bird species
with migratory status. Consequences were identified in relation to the role that nongovernmental organizations (NGOs) play
in land-use conflicts and the actions that MARNR could take in the future to prevent and solve similar situations. 相似文献
615.
A binary response estimation procedure using contingent valuation data is proposed for estimating the incremental environmental benefits associated with the use of constructed wetlands to control agricultural waste-water runoff. The model uses two binary responses per individual while circumventing the non-independence problems associated with follow-up valuation questions. Case study results suggest that the methodology provides a potentially effective means for measuring the non-market benefits of constructed wetlands in addition to water-quality maintenance.1998 Academic Press 相似文献
616.
Judy Z. Drexier Barbara L. Bedford Arthur T DeGaetano Donald I. Siegel 《Journal of the American Water Resources Association》1999,35(4):753-769
ABSTRACT: Few water budgets exist for specific types of wetlands such as peatlands, even though such information provides the basis from which to investigate linkages between wetlands and upland ecosystems. In this study, we first determined the water budget and then estimated nutrient loading from an upland farm field into a 1.5 ha, kettle-block peatland. The wetland contains highly anisotropic peat and has no distinct, active layer of groundwater flow. We estimated the depth of the active layer using Fick's law of diffusion and quantified groundwater flow using a chemical mass balance model. Evapotranspiration was determined using MORECS, a semi-physical model based on the Penman-Monteith approach. Precipitation and surface outflow were measured using physical means. Groundwater provided the major inflow, 84 percent (44,418 m3) in 1993 and 88 percent (68,311 m3) in 1994. Surface outflow represented 54 percent (28,763 m3) of total outflows in 1993 and 48 percent (37,078 m3) in 1994. A comparison of several published water budgets for wetlands and lakes showed that error estimates for hydrologic components in this study are well within the range of error estimates calculated in other studies. Groundwater inflow estimates and nutrient concentrations of three springs were used to estimate agricultural nutrient loading to the site. During the study period, nutrient loading into the peatland via groundwater discharge averaged 24.74 kg K ha-1, 1.83 kg total inorganic P had, and 21.81 kg NO3-N ha-1. 相似文献
617.
Zhenfeng Han Ying Miao Jing Dong Zhiqiang Shen Yuexi Zhou Shan Liu Chunping Yang 《Frontiers of Environmental Science & Engineering》2019,13(4):52
618.
为探讨石灰石沟-潜流堆肥湿地系统处理酸性矿山废水(AMD)的效果及影响因素,进行了6个月模拟试验,测定出水水质和植物生长等相关的影响因素.结果表明,石灰石沟可有效提高AMD的pH值,降低其酸度与重金属含量,但随着石灰石沟中氢氧化物的积累,后期处理性能下降;堆肥湿地可显著降低AMD的酸度与重金属,出水酸度随时间持续降低,出水的Cd、Pb在检测限以下,Zn、Cu平均浓度分别为1.8mg/L, 2.6μg/L,均达到农业灌溉水标准,而无前置堆肥的普通湿地后期Cd、Zn、Cu偏高;东南景天在湿地系统也能正常富积Cd/Zn;狭叶香蒲使堆肥湿地的产碱过程受到抑制,出水酸度升高,但其对堆肥湿地的重金属去除没有产生显著影响. 相似文献
619.
为研究海菜花水培经济湿地对农田低污染水的净化效能及投放螺蛳对水体净化的影响,在进水ρ(TN)、ρ(NO3--N)、ρ(TP)分别为(5.08±0.14)、(4.71±0.15)、(0.10±0.03)mg/L条件下,构建了无螺组(海菜花湿地)、有螺组(海菜花-螺蛳经济湿地)和空白组(无海菜花和螺蛳湿地)3种湿地,对比不同HRT(水力停留时间)对水质处理效果的影响,并考察了其经济效益. 结果表明:①HRT为7 d时,无螺组对TN、NO3--N和TP的去除率分别为55.6%±5.8%、62.6%±5.8%和76.3%±4.8%,有螺组分别为50.8%±5.5%、61.2%±6.3%和75.5%±3.9%;HRT为42 d时的污染物去除率与HRT为28 d时相当,并且有螺组和无螺组也相当,对TN、NO3--N和TP的去除率分别在76.8%、92.4%和84.8%以上. ②HRT为7和42 d时,投放螺蛳对N、P的去除均表现为抑制作用;HRT为7 d时有螺组浊度显著降低(P<0.05). ③HRT为7 d时,有螺组和无螺组对TN、TP的处理量均在800和228 kg/(hm2·a)以上,显著高于HRT为42 d〔141、46 kg/(hm2·a)〕时. ④HRT为7 d的有螺组经济效益最高,为20.3×104元/(hm2·a),其中海菜花收益为15.4×104元/(hm2·a),投加螺蛳增加经济效益为4.9×104元/(hm2·a). 综合考虑对农田低污染水的净化效能和经济效益,优选HRT为7 d的海菜花-螺蛳经济湿地处理农田低污染水. 相似文献
620.