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131.
The ability of Section 404 of the Clean Water Act to act as an effective, efficient, and equitable land-use planning tool
was assessed through a survey of Section 404 permits in Wisconsin. In a six-month period of permitting, the 404 program reduced
wetland losses in the state by 15%. Several factors were examined that may affect permit decisions; these factors are water
dependency, alternatives, project type, wetland type, and public or agency comments. Only the water dependency of the project
had a statistically significant effect on permit decisions, although development projects that were perceived to provide public
good were more likely to be permitted. Environmental impacts of a proposed fill project were not adequately assessed in any
of the permit decisions. Because of the way Section 404 is interpreted and administered by the US Army Corps of Engineers,
increasing net benefits and achieving an equitable distribution of those benefits is difficult. The corps does not perform
any functional evaluations of wetlands nor do they attempt to measure economic value and environmental impacts. In addition,
the 404 review process is, in effect, inaccessible to the public. The de facto interpretations of the Section 404 regulations
and a lack of program funding and trained personnel all contribute to the program's ineffectiveness. 相似文献
132.
Habituation and its role in the dear enemy effect was investigated in a population of green frogs, Rana clamitans. Green frogs have a prolonged breeding season, and males defend territories centered around suitable oviposition sites. We
tested the prediction that male green frogs will habituate to broadcasts of synthetic conspecific stimuli. Our results indicate
that male green frogs can discriminate familiar from unfamiliar stimuli. We suggest that habituation helps to mediate the
territorial interactions between male green frogs. Strangers present a greater threat than familiar neighbors. By habituating
to the advertisement vocalizations of their near neighbors, males avoid costly interactions with individuals that are not
a major threat to their territories.
Received: 20 July 1998 / Accepted after revision: 6 September 1998 相似文献
133.
134.
Restoring piscivorous fish populations in the Laurentian Great Lakes causes seabird dietary change 总被引:1,自引:0,他引:1
Hebert CE Weseloh DV Idrissi A Arts MT O'Gorman R Gorman OT Locke B Madenjian CP Roseman EF 《Ecology》2008,89(4):891-897
Ecosystem change often affects the structure of aquatic communities thereby regulating how much and by what pathways energy and critical nutrients flow through food webs. The availability of energy and essential nutrients to top predators such as seabirds that rely on resources near the water's surface will be affected by changes in pelagic prey abundance. Here, we present results from analysis of a 25-year data set documenting dietary change in a predatory seabird from the Laurentian Great Lakes. We reveal significant declines in trophic position and alterations in energy and nutrient flow over time. Temporal changes in seabird diet tracked decreases in pelagic prey fish abundance. As pelagic prey abundance declined, birds consumed less aquatic prey and more terrestrial food. This pattern was consistent across all five large lake ecosystems. Declines in prey fish abundance may have primarily been the result of predation by stocked piscivorous fishes, but other lake-specific factors were likely also important. Natural resource management activities can have unintended consequences for nontarget ecosystem components. Reductions in pelagic prey abundance have reduced the capacity of the Great Lakes to support the energetic requirements of surface-feeding seabirds. In an environment characterized by increasingly limited pelagic fish resources, they are being offered a Hobsonian choice: switch to less nutritious terrestrial prey or go hungry. 相似文献
135.
Nalli S Horn OJ Grochowalski AR Cooper DG Nicell JA 《Environmental pollution (Barking, Essex : 1987)》2006,140(1):181-185
2-Ethylhexanol has been identified as a volatile organic compound (VOC) that contributes to the deterioration of indoor air quality. Plasticizers are common components of dust and building materials and are shown to be degraded by a variety of bacteria and fungi to produce 2-ethylhexanol and other metabolites. Of these, the 2-ethylhexanol has significant volatility and was observed in appreciable quantities. The degree to which 2-ethylhexanol is observed as a VOC in air samples would be limited by the fact that many of the microorganisms that are capable of producing this compound are also able to oxidize it to 2-ethylhexanoic acid, which is much less volatile. It is argued that an abiotic degradation mechanism of plasticizers that results in the generation of 2-ethylhexanol is unlikely and, if this did occur, other metabolites should have been observed. Thus, the microbial degradation of plasticizers is the most likely source of 2-ethylhexanol in indoor air. 相似文献
136.
Nitrate removal effectiveness of a riparian buffer along a small agricultural stream in western Oregon 总被引:3,自引:0,他引:3
Wigington PJ Griffith SM Field JA Baham JE Horwath WR Owen J Davis JH Rain SC Steiner JJ 《Journal of environmental quality》2003,32(1):162-170
The Willamette Valley of Oregon has extensive areas of poorly drained, commercial grass seed lands. Little is know about the ability of riparian areas in these settings to reduce nitrate in water draining from grass seed fields. We established two study sites with similar soils and hydrology but contrasting riparian vegetation along an intermittent stream that drains perennial ryegrass (Lolium perenne L.) fields in the Willamette Valley of western Oregon. We installed a series of nested piezometers along three transects at each site to examine NO3-N in shallow ground water in grass seed fields and riparian areas. Results showed that a noncultivated riparian zone comprised of grasses and herbaceous vegetation significantly reduced NO3-N concentrations of shallow ground water moving from grass seed fields. Darcy's law-based estimates of shallow ground water flow through riparian zone A/E horizons revealed that this water flowpath could account for only a very small percentage of the streamflow. Even though there is great potential for NO3-N to be reduced as water moves through the noncultivated riparian zone with grass-herbaceous vegetation, the potential was not fully realized because only a small proportion of the stream flow interacts with riparian zone soils. Consequently, effective NO3-N water quality management in poorly drained landscapes similar to the study watershed is primarily dependent on implementation of sound agricultural practices within grass seed fields and is less influenced by riparian zone vegetation. Wise fertilizer application rates and timing are key management tools to reduce export of NO3-N in stream waters. 相似文献
137.
A. D. Owen 《Resources Policy》1980,6(4):343-344
138.
Ian C. Simcock Audrey Lamouroux Neil J. Sebire Susan C. Shelmerdine Owen J. Arthurs 《黑龙江环境通报》2023,43(7):937-949
Autopsy investigations provide valuable information regarding fetal death that can assist in the parental bereavement process, and influence future pregnancies, but conventional autopsy is often declined by parents because of its invasive approach. This has led to the development of less-invasive autopsy investigations based on imaging technology to provide a more accessible and acceptable choice for parents when investigating their loss. Whilst the development and use of more conventional clinical imaging techniques (radiographs, CT, MRI, US) are well described in the literature for fetuses over 20 weeks of gestational age, these investigations have limited diagnostic accuracy in imaging smaller fetuses. Techniques such as ultra-high-field MRI (>3T) and micro-focus computed tomography have been shown to have higher diagnostic accuracy whilst still being acceptable to parents. By further developing and increasing the availability of these more innovative imaging techniques, parents will be provided with a greater choice of acceptable options to investigate their loss, which may in turn increase their uptake. We provide a narrative review focussing on the development of high-resolution, non-invasive imaging techniques to evaluate early gestational pregnancy loss. 相似文献