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31.
32.
Katrina Mullan Andreas Kontoleon Timothy M. Swanson Shiqiu Zhang 《Environmental management》2010,45(3):513-525
In this study, we estimated the impact on local household livelihoods of the Natural Forest Protection Program (NFPP), which
is the largest logging-ban program in the world, which aims to protect watersheds and conserve natural forests. In doing so,
we used a series of microeconometric policy-evaluation techniques to assess the impacts of the NFPP on two interrelated facets
of household livelihoods: income and off-farm labor supply. We found that the NFPP has had a negative impact on incomes from
timber harvesting but has actually had a positive impact on total household incomes from all sources. Furthermore, we found
that off-farm labor supply outside the village has increased more rapidly in NFPP than in non-NFPP areas. Based on these results,
policy implications for household livelihoods were drawn and are presented herein. 相似文献
33.
34.
Mitchell D. Erickson Steven E. Swanson Thomas M. Sack Daniel T. Heggem 《Chemosphere》1986,15(9-12):1261-1264
Polychlorinated dibenzofurans (PCDFs) are formed in the combustion of polychlorinated biphenyls (PCBs), trichlorobenzene, and tetrachloroethylene transformer dielectric fluids. Polychlorinated dibenzodioxins (PCDDs) are also observed, but at lower levels. 相似文献
35.
Robert K. Hall David Guiliano Sherman Swanson Michael J. Philbin John Lin Joan L. Aron Robin J. Schafer Daniel T. Heggem 《Environmental monitoring and assessment》2014,186(4):2413-2433
Prioritizing total maximum daily load (TMDL) development starts by considering the scope and severity of water pollution and risks to public health and aquatic life. Methodology using quantitative assessments of in-stream water quality is appropriate and effective for point source (PS) dominated discharge, but less so in watersheds with mostly nonpoint source (NPS) related impairments. For NPSs, prioritization in TMDL development and implementation of associated best management practices should focus on restoration of ecosystem physical functions, including how restoration effectiveness depends on design, maintenance and placement within the watershed. To refine the approach to TMDL development, regulators and stakeholders must first ask if the watershed, or ecosystem, is at risk of losing riparian or other ecologically based physical attributes and processes. If so, the next step is an assessment of the spatial arrangement of functionality with a focus on the at-risk areas that could be lost, or could, with some help, regain functions. Evaluating stream and wetland riparian function has advantages over the traditional means of water quality and biological assessments for NPS TMDL development. Understanding how an ecosystem functions enables stakeholders and regulators to determine the severity of problem(s), identify source(s) of impairment, and predict and avoid a decline in water quality. The Upper Reese River, Nevada, provides an example of water quality impairment caused by NPS pollution. In this river basin, stream and wetland riparian proper functioning condition (PFC) protocol, water quality data, and remote sensing imagery were used to identify sediment sources, transport, distribution, and its impact on water quality and aquatic resources. This study found that assessments of ecological function could be used to generate leading (early) indicators of water quality degradation for targeting pollution control measures, while traditional in-stream water quality monitoring lagged in response to the deterioration in ecological functions. 相似文献
36.
37.
Hilda Kwan Sherman Swanson 《Journal of the American Water Resources Association》2014,50(6):1448-1448
38.
Two samples of tab water and double distilled water were chlorinated using chlorine gas. A series of PCDFs could be identified from these experiments, however no PCDDs could be found. The two water samples gave very similar isomeric patterns (
.
. tetra-CDFs), however the congener profile (Cl4 --- Cl8) was different. These experiments indicate that all products formed by chlorination reactions are potentially contaminated by PCDFs by a specific “chlorine pattern”. 相似文献
39.
Thomas J. Myers Sherman Swanson 《Journal of the American Water Resources Association》1991,27(4):667-677
ABSTRACT: The quality of stream habitat varies for a variety of natural and anthropogenic reasons not identified by a condition index. However, many people use condition indices to indicate management needs or even direction. To better sort natural from livestock influences, stream types and levels of ungulate bank damage were regulated to estimates of aquatic habitat condition index and stream width parameters in a large existing stream inventory data base. Pool/riffle ratio, pool structure, stream bottom materials, soil stability, and vegetation type varied significantly with stream type. Pool/riffle ratio, soil and vegetation stability varied significantly with ungulate bank damage level. Soil and vegetation stability were highly cross-correlated. Riparian area width did not vary significantly with either stream type or ungulate bank damage. Variation among stream types indicates that riparian management and monitoring should be stream type and reach specific. 相似文献
40.
Thomas J. Myers Sherman Swanson 《Journal of the American Water Resources Association》1996,32(2):241-252
ABSTRACT: We compared the recovery from abusive grazing of aquatic habitat due to different range management on two geomorphically similar rangeland streams in northwest Nevada. Managers excluded livestock from the Mahogany Creek watershed from 1976 to 1990 while allowing rotation of rest grazing on its tributary Summer Camp Creek. Bank stability, defined as the lack of apparent bank erosion or deposition, improved through the study period on both streams, but periodic grazing and flooding decreased stability more on Summer Camp Creek than flooding alone on Mahogany Creek. Pool quantity and quality on each stream decreased because of coarse woody debris removal and sediment deposition during a drought. Fine stream bottom sediments decreased five years after the removal of livestock, but sedimentation increased during low flows in both streams below road crossings. Tree cover increased 35 percent at both streams. Thus, recovery of stability and cover and decreased sedimentation are compatible with rotation of rest grazing on Summer Camp Creek. Width/depth ratio and gravel/cobble percent did not change because they are inherently stable in this stream type. Management activities such as coarse woody debris removal limited pool recover and road crossings increased sedimentation. 相似文献