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Many California streams have been adversely affected by sedimentation caused by historic and current land uses, including
timber harvesting. The impacts of timber harvesting and logging transportation systems on erosion and sediment delivery can
be directly measured, modeled, or inferred from water quality measurements. California regulatory agencies, researchers, and
land owners have adopted turbidity monitoring to determine effects of forest management practices on suspended sediment loads
and water quality at watershed, project, and site scales. Watershed-scale trends in sediment discharge and responses to current
forest practices may be estimated from data collected at automated sampling stations that measure turbidity, stream flow,
suspended sediment concentrations, and other water quality parameters. Future results from these studies will provide a basis
for assessing the effectiveness of modern forest practice regulations in protecting water quality. At the project scale, manual
sampling of water column turbidity during high stream flow events within and downstream from active timber harvest plans can
identify emerging sediment sources. Remedial actions can then be taken by managers to prevent or mitigate water quality impacts.
At the site scale, manual turbidity sampling during storms or high stream flow events at sites located upstream and downstream
from new, upgraded, or decommissioned stream crossings has proven to be a valuable way to determine whether measures taken
to prevent post-construction erosion and sediment production are effective. Turbidity monitoring at the project and site scales
is therefore an important tool for adaptive management. Uncertainty regarding the effects of current forest practices must
be resolved through watershed-scale experiments. In the short term, this uncertainty will stimulate increased use of project
and site-scale monitoring. 相似文献
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In recent years, many political parties have created new forms of affiliation and have justified the blurring of membership boundaries with claims that sympathisers would be more representative of the electorate and less radical. Such claims are based on ‘popular wisdom’ inspired by John May’s ‘special law of curvilinearity’, which states that activists hold more extreme views than voters and elites. When this expectation has been tested, results have been at best inconclusive; but testing has so far never used a single survey to compare different groups. Using an online survey of Europe Ecologie Les Verts party members and their extended networks (affiliated supporters, lapsed members, sympathisers), relationships between ideological differences and degree of investment in party activities and decision-making are analysed. The results, contradicting May’s special law along all ideological dimensions other than intra-party democracy, can be explained if May’s narrowly instrumental assumptions about preference formation are rejected. 相似文献
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Faucher K Fichet D Miramand P Lagardère JP 《Environmental pollution (Barking, Essex : 1987)》2008,151(1):148-157
The effect of chronic exposure to a low concentration (0.5 microg l(-1)) of cadmium ions was investigated on escape behaviour of sea bass, Dicentrarchus labrax, using video analysis. Observations were also performed on the microanatomy of lateral system neuromasts. When fish were exposed for 4h per day over 8 days to the cadmium ions, most of both types of neuromasts observed remained intact. However, some of them presented damaged sensory maculae. Whereas before cadmium exposure, fish responded positively to nearly all the lateral system stimulations, after exposure they decreased by about 10% their positive responses to stimulations. From the 15th day after the beginning of cadmium exposure, neuromasts presented progressively less damage, cadmium accumulation in gills and scales decreased significantly and fish escape behaviour had recovered. This study presents a new concept in ecotoxicology: using behavioural change to reveal the effects of pollution levels, scarcely detectable by currently used techniques (physiological responses). 相似文献
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Faucher Stéphane Le Coustumer Philippe Lespes Gaëtane 《Environmental science and pollution research international》2019,26(6):5267-5281
Environmental Science and Pollution Research - This article deals with analytical chemistry devoted to nano-objects. A short review presents nano-objects, their singularity in relation to their... 相似文献
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