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31.
Differences between scientist and policy-maker response types and times, or the “how” and “when” of action, constrain effective
water resource management in suburbanizing watersheds. Policy-makers are often rushed to find a single policy that can be
applied across an entire, homogeneous, geopolitical region, whereas scientists undertake multiyear research projects to appreciate
the complex interactions occurring within heterogeneous catchments. As a result, watershed management is often practiced with
science and policy out of synch. Meanwhile, development pressures in suburban watersheds create changes in the social and
physical fabric and pose a moving target for science and policy. Recent and anticipated advances in the scientific understanding
of urbanized catchment hydrology and pollutant transport suggest that management should become increasingly sensitive to spatial
heterogeneities in watershed features, such as soil types, terrain slopes, and seasonal watertable profiles. Toward this end,
policy-makers should encourage funding scientific research that characterizes the impacts of these watershed heterogeneities
within a geopolitical zoning and development framework. 相似文献
32.
Steven J. Paustian Robert L. Beschta 《Journal of the American Water Resources Association》1979,15(1):144-154
ABSTRACT: Armored stream segments may affect the suspended sediment regime of small mountain streams in western Oregon by the release of fine sediments stored in the bed gravels. Sieve analysis of bed materials indicated that at least 30 percent of the suspended sediment yield for the 1975–76 winter had been stored in the streambed. Suspended sediment concentrations during storm-generated runoff were influenced by stream discharge and hydrograph characteristics. Sediment-discharge relations for individual storms were characterized by hysteresis loops. A seasonal flushing of fines was shown by a progressive decrease in the ratio of suspended sediment to stream discharge during the winter runoff period. 相似文献
33.
Recreational impact was measured on eight beaches in Glen Canyon National Recreation Area and 15 beaches in Grand Canyon National Park using permanently located transects and plots. Recreational impact indices included densities of human trash and charcoal and a measure of sand discoloration due to charcoal. Significant increases in the indices occurred on several Glen Canyon beaches over a seven-month period. Sand discoloration became significantly higher over all Glen Canyon beaches during the same time period. All indices were significantly higher in Glen Canyon than on similar Grand Canyon beaches. These differences are probably due to differences in: (a) level of impacts tolerated by the respective management regimes and, (b) in the number of user days among the two National Park Service administrative units. Management alternatives are presented for reversing the present trends of recreational impact on Glen Canyon beaches. 相似文献
34.
35.
Abstract: Nongame bird hunting is a critical activity of the Zuni people of the southwestern United States. To help determine whether their current hunting practices may be negatively affecting bird populations on the Zuni Reservation, we interviewed 98 Zuni hunters. Nongame bird hunting was practiced by a large portion of Zuni males (45%); the most active age group was 20- to 49-year-olds. The rate a species was hunted was not a function of its abundance at Zuni but seemed instead to be related to its cultural demand. Five species—bluebirds ( Sialia currucoides , S. mexicana ), Northern Flicker ( Colaptes auratus ), woodpeckers ( Picoides villosus , P. pubescens , Melanerpes lewis ), Steller's Jay ( Cyanocitta stelleri ), and American Kestrel ( Falco sparverius )—made up 77% of all birds taken. The two most heavily hunted species were each taken in numbers> 10,000 individuals per year. Although the greatest number of hunters were active in autumn, 31% hunted in spring, despite discouragement by the tribal government. Habitats favored by hunters were coniferous forests and riparian areas. Rates of hunting of nongame birds at Zuni equaled or exceeded those reported for game birds hunted by indigenous hunters in the Neotropics and New Mexico. The Zuni believe that some heavily hunted species are decreasing in number because of hunting. Although we cannot prove this at present, we suggest measures to mitigate possible overhunting, including the creation of refugia and a reduction of spring hunting. 相似文献
36.
Kennett SA 《Environmental management》2002,30(5):0595-0608
Biosphere greenhouse gas (GHG) management consists of preserving and enhancing terrestrial carbon pools and producing biomass
as a fossil fuel substitute. The discussion of this topic has focused primarily on carbon-accounting and project-level issues,
particularly relating to carbon sequestration as a source of emissions credits under the Kyoto Protocol. While international
consensus on these matters is needed, this paper argues that an important domestic policy agenda also deserves attention.
National policies for biosphere GHG management are necessary to bring about large-scale changes in land-use, forestry, and
agricultural practices and can address some of the technical and policy issues that have proven to be particularly problematic
from carbon-accounting and project-level perspectives. These policies should minimize land-use and resource-management conflicts,
account for collateral benefits, and ensure institutional compatibility with existing resource-management regimes. Issues
relating to project permanence, leakage, and transaction costs should also be addressed. A range of policy instruments should
be used and biosphere GHG management should be one component of an integrated approach to environmental and resource management.
Countries promoting biosphere GHG management as an important element of their climate change strategies should be developing
these domestic policies to complement international negotiations and to demonstrate that carbon sequestration and biomass
production can make an effective contribution to the stabilization of atmospheric GHG concentrations. 相似文献
37.
This article presents a case study of an accelerated cleanup conducted by EPA at the Adams Plating Company (APC) Superfund site near Lansing, Michigan. The APC site remediation was a Superfund EPA-lead project under the remedial program in Region 5. An accelerated cleanup was possible at the APC site by consistently identifying, evaluating, and implementing opportunities to streamline the remedial investigation (RI) and remedial design (RD) process. Streamlining opportunities were discovered and implemented in both the technical and administrative aspects of the project. Streamlining components used to accelerate the remedial process included: (1) extensive use of field screening techniques during the Phase II RI; (2) a focused feasibility study (FS) that evaluated only practical alternatives; (3) maintaining project momentum by initiating the RD concurrent with the issuance of the Record of Decision (ROD); (4) a highly accelerated RD with limited predesign work; (5) elimination of the transition period between RD and remedial action (RA) project phases; (6) frequent and effective communication, coordination, and cooperation between all parties involved (EPA, Michigan Department of Natural Resources (MDNR), technical contractor, PRC Environmental Management, Inc. (PRC), and the public); (7) maintaining a consistent project team throughout project duration; and (8) the setting of aggressive project goals. 相似文献
38.
Impact of Land Use on Soluble Organic Nitrogen in Soil 总被引:5,自引:0,他引:5
Victoria B. Willett James J. Green Andrew J. Macdonald John A. Baddeley Georg Cadisch Steven M. J. Francis Keith W. T. Goulding Gary Saunders Elizabeth A. Stockdale Christine A. Watson David L. Jones 《Water, Air, & Soil Pollution: Focus》2004,4(6):53-60
Although it has been hypothesized that soluble organic nitrogen (SON) plays a central role in regulating productivity in some terrestrial ecosystems, the factors controlling the size of the SON pool in soil remain poorly understood. Therefore our principal aim in this work was to assess the impact of seven different land use systems (rough and managed grassland, deciduous and coniferous woodland, heathland, wetland and tilled land) on the size of the SON and inorganic N (NO
3
–
, NH
4
+
) pools in the surface soil layer (0–15 cm). After extraction with deionised water, we found that in most cases the size of the water extractable organic N (WEON) pool was similar in size to the inorganic N pool. In contrast, the KCl extractable organic N (KClEON) pool constituted the dominant form of soluble N in soils under all land uses, perhaps indicating that significant amounts were held on the soil exchange phase. In contrast to inorganic N, which varied significantly with land use, the size of the KClEON and WEON pool was similar for all land uses with the exception of KClEON in tilled land, where significantly lower amounts were observed. We conclude that SON constitutes an important soil N pool in a broad range of land uses, and that its role in microbial N assimilation, plant nutrition and ecosystem responses to atmospheric N deposition warrants further attention.
SAFRD, University of Newcastle, Newcastle-upon-Tyne, NE1 7RU, U.K. 相似文献
39.
Michael D. Cameron Zachary D. Post James D. Stahl Joachim Haselbach Steven D. Aust 《Environmental science and pollution research international》2000,7(3):130-134
When Phanerochaete chrysosporium was cultured using conditions which promote the expression of cellobiose dehydrogenase (CDH), but not the ligninolytic peroxidases, the fungus effectively solubilized and mineralized an insoluble, crosslinked polyacrylate and an insoluble polyacrylate/polyacrylamide copolymer. Addition of iron to the cultures increased CDH activity in the cultures and the rate and extent of solubilization and mineralization of both polymers. Solubilization of both polymers was observed when incubated with purified CDH, ferric iron and hydrogen peroxide. 相似文献
40.
Burr G Hume M Ricke S Nisbet D Gatlin D 《Journal of environmental science and health. Part. B》2008,43(3):253-260
This study examined the effects of brewers yeast, fructooligosaccharide (FOS), and GroBiotic-A, a mixture of partially autolyzed brewers yeast, dairy components and dried fermentation products, on the intestinal microbial community of red drum, Sciaenops ocellatus. Gastrointestinal (GI) tracts were aseptically removed from three sub-adult red drum previously maintained on a commercial diet and placed in an anaerobic chamber. Intestinal contents were removed, diluted and incubated in vitro in one of four liquid media: normal diet alone, diet + 2% (w/w) GroBiotic-A, diet + 2% brewers yeast, and diet + 2% FOS. After 24 and 48 h of incubation at 25 degrees C, supernatants were removed for volatile fatty acid (VFA) analysis and DNA was extracted for denaturing gradient gel electrophoresis (DGGE) analysis. Polymerase chain reaction (PCR) was performed on a highly conserved region of M 16S rDNA and the amplicons were subjected to DGGE. The microbial community (MC) fingerprint was used to distinguish microbial populations. The intestinal contents incubated with GroBiotic-A had significantly (P<0.05) higher acetate and total VFA concentrations at 48 h compared to the other treatments. DGGE analysis demonstrated that the microbial community was significantly altered by Grobiotic-A and brewers yeast. 相似文献