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11.
Results from a survey of power utility biologists indicate that terrestrial biodiversity is considered a major issue by only a few utilities; however, a majority believe it may be a future issue. Over half of the respondents indicated that their company is involved in some management for biodiversity, and nearly all feel that it should be a goal for resource management. Only a few utilities are funding biodiversity research, but a majority felt more research was needed. Generally, larger utilities with extensive land holdings had greater opportunities and resources for biodiversity management. Biodiversity will most likely be a concern with transmission rights-of-way construction and maintenance, endangered species issues and general land resource management, including mining reclamation and hydro relicensing commitments. Over half of the companies surveyed have established voluntary partnerships with management groups, and biodiversity is a goal in nearly all the joint projects. Endangered species management and protection, prevention of forest fragmentation, wetland protection, and habitat creation and protection are the most common partnerships involving utility companies. Common management practices and unique approaches are presented, along with details of the survey. 相似文献
12.
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
13.
Aida Mendez Gary R. Sands Berangere Basin Chang‐Xing Jin Paul J. Wotzka 《Journal of the American Water Resources Association》2004,40(2):385-400
ABSTRACT: Surface and subsurface drainage make crop production economically viable in much of southern Minnesota because drainage allows timely field operations and protects field crops from extended periods of flooded soil conditions. However, subsurface drainage has been shown to increase nitrate/nitrogen losses to receiving waters. When engaging in drainage activities, farmers are increasingly being asked to consider, apart from the economic profit, the environmental impact of drainage. The Agricultural Drainage and Pesticide Transport model (ADAPT) was used in this study to evaluate the impact of subsurface drainage design on the soil water balance over a two‐year period during which observed drainage discharge data were available. Twelve modeling scenarios incorporated four drainage coefficients (DC), 0.64 cm/d, 0.95 cm/d, 1.27 cm/d, and 1.91 cm/d, and three drain depths, 0.84 m, 1.15 m, and 1.45 m. The baseline condition corresponded to the drainage system specifications at the field site: a drain depth and spacing of 1.45 m and 28 m, respectively (DC of 0.64 cm/d). The results of the two‐year simulation suggested that for a given drainage coefficient, soils with the shallower drains (but equal DC) generally have less subsurface drainage and can produce more runoff (but reduced total discharge) and evapotranspiration. The results also suggested that it may be possible to design for both water/nitrate/nitrogen reduction and crop water needs. 相似文献
14.
Donna M. Cosgrove Gary S. Johnson 《Journal of the American Water Resources Association》2004,40(6):1469-1482
ABSTRACT: Increasing demands on western water are causing a mounting need for the conjunctive management of surface water and ground water resources. Under western water law, the senior water rights holder has priority over the junior water rights holder in times of water shortage. Water managers have been reluctant to conjunctively manage surface water and ground water resources because of the difficulty of quantification of the impacts to surface water resources from ground water stresses. Impacts from ground water use can take years to propagate through an aquifer system. Prediction of the degree of impact to surface water resources over time and the spatial distribution of impacts is very difficult. Response functions mathematically describe the relationship between a unit ground water stress applied at a specific location and stream depletion or aquifer water level change elsewhere in the system. Response functions can be used to help quantify the spatial and temporal impacts to surface water resources caused by ground water pumping. This paper describes the theory of response functions and presents an application of transient response functions in the Snake River Plain, Idaho. Transient response functions can be used to facilitate the conjunctive management of surface and ground water not only in the eastern Snake River Plain basin, but also in similar basins throughout the western United States. 相似文献
15.
Gary M. Bucciarelli Daniel Suh Avery Davis Lamb Dave Roberts Debra Sharpton H. Bradley Shaffer Robert N. Fisher Lee B. Kats 《Conservation biology》2019,33(1):122-131
Introductions of non-native predators often reduce biodiversity and affect natural predator–prey relationships and may increase the abundance of potential disease vectors (e.g., mosquitoes) indirectly through competition or predation cascades. The Santa Monica Mountains (California, U.S.A.), situated in a global biodiversity hotspot, is an area of conservation concern due to climate change, urbanization, and the introduction of non-native species. We examined the effect of non-native crayfish (Procambarus clarkii) on an existing native predator, dragonfly nymphs (Aeshna sp.), and their mosquito larvae (Anopheles sp.) prey. We used laboratory experiments to compare the predation efficiency of both predators, separately and together, and field data on counts of dragonfly nymphs and mosquito larvae sampled from 13 local streams. We predicted a lower predation efficiency of crayfish compared with native dragonfly nymphs and a reduced predation efficiency of dragonfly nymphs in the presence of crayfish. Dragonfly nymphs were an order of magnitude more efficient predators than crayfish, and dragonfly nymph predation efficiency was reduced in the presence of crayfish. Field count data showed that populations of dragonfly nymphs and mosquito larvae were strongly correlated with crayfish presence in streams, such that sites with crayfish tended to have fewer dragonfly nymphs and more mosquito larvae. Under natural conditions, it is likely that crayfish reduce the abundance of dragonfly nymphs and their predation efficiency and thereby, directly and indirectly, lead to higher mosquito populations and a loss of ecosystem services related to disease vector control. 相似文献
16.
Shahid Parvez Glenn E. Rice Linda K. Teuschler Jane Ellen Simmons Thomas F. Speth Susan D. Richardson Richard J. Miltner E. Sidney Hunter III Jonathan G. Pressman Lillian F. Strader Gary R. Klinefelter Jerome M. Goldman Michael G. Narotsky 《环境科学学报(英文版)》2017,29(8):311-321
A method based on regression modeling was developed to discern the contribution of component chemicals to the toxicity of highly complex, environmentally realistic mixtures of disinfection byproducts(DBPs). Chemical disinfection of drinking water forms DBP mixtures.Because of concerns about possible reproductive and developmental toxicity, a whole mixture(WM) of DBPs produced by chlorination of a water concentrate was administered as drinking water to Sprague–Dawley(S–D) rats in a multigenerational study. Age of puberty acquisition,i.e., preputial separation(PPS) and vaginal opening(VO), was examined in male and female offspring, respectively. When compared to controls, a slight, but statistically significant delay in puberty acquisition was observed in females but not in males. WM-induced differences in the age at puberty acquisition were compared to those reported in S–D rats administered either a defined mixture(DM) of nine regulated DBPs or individual DBPs. Regression models were developed using individual animal data on age at PPS or VO from the DM study. Puberty acquisition data reported in the WM and individual DBP studies were then compared with the DM models. The delay in puberty acquisition observed in the WM-treated female rats could not be distinguished from delays predicted by the DM regression model, suggesting that the nine regulated DBPs in the DM might account for much of the delay observed in the WM. This method is applicable to mixtures of other types of chemicals and other endpoints. 相似文献
17.
18.
Great Basin Land Management Planning Using Ecological Modeling 总被引:1,自引:1,他引:0
This report describes a land management modeling effort that analyzed potential impacts of proposed actions under an updated
Bureau of Land Management Resource Management Plan that will guide management for 20 years on 4.6 million hectares in the
Great Basin ecoregion of the United States. State-and-transition models that included vegetation data, fire histories, and
many parameters (i.e., rates of succession, fire return intervals, outcomes of management actions, and invasion rates of native
and nonnative invasive species) were developed through workshops with scientific experts and range management specialists.
Alternative restoration scenarios included continuation of current management, full fire suppression, wildfire use in designated fire use zones, wildfire use in resilient vegetation types only, restoration with a tenfold budget increase, no restoration treatments, and no livestock grazing. Under all the scenarios, cover of vegetation states with native perennial understory declined and was replaced by tree-invaded
and weed-dominated states. The greatest differences among alternative management scenarios resulted from the use of fire as
a tool to maintain native understory. Among restoration scenarios, only the scenario assuming a tenfold budget increase had
a more desirable outcome than the current management scenario. Removal of livestock alone had little effect on vegetation
resilience. Rather, active restoration was required. The predictive power of the model was limited by current understanding
of Great Basin vegetation dynamics and data needs including statistically valid monitoring of restoration treatments, invasiveness
and invasibility, and fire histories. The authors suggest that such computer models can be useful tools for systematic analysis
of potential impacts in land use planning. However, for a modeling effort to be productive, the management situation must
be conducive to open communication among land management agencies and partner entities, including nonprofit organizations. 相似文献
19.
Three geomorphic considerations that underpin the design and implementation of realistic and strategic river conservation
and rehabilitation programs that work with the nature are outlined. First, the importance of appreciating the inherent diversity
of river forms and processes is discussed. Second, river dynamics are appraised, framing the contemporary behavioral regime
of a reach in relation to system evolution to explain changes to river character and behavior over time. Third, the trajectory
of a reach is framed in relation to downstream patterns of river types, analyzing landscape connectivity at the catchment
scale to interpret geomorphic river recovery potential. The application of these principles is demonstrated using extensive
catchment-scale analyses of geomorphic river responses to human disturbance in the Bega and Upper Hunter catchments in southeastern
Australia. Differing implications for reach- and catchment-scale rehabilitation planning prompt the imperative that management
practices work with nature rather than strive to ‘fight the site.’ 相似文献
20.
College students spend much of their time on campus engaged in activities that require sustained directed attention, which may lead to attention fatigue. They would benefit from campus settings that provide effective restoration breaks and allow them to return to their work cognitively refreshed. Studies have found direct exposure to nature, viewing nature through windows, and viewing images of nature are restorative. In the present study, college students, instructed to imagine themselves cognitively fatigued, rated the perceived restorativeness of indoor campus settings that varied by view of nature: some had no views of nature, some had window views of nature with built structures present, and some had views of simulated nature depicted as large nature murals. Students rated settings with views of dramatic nature murals, especially those with water, more restorative than settings with window views of real, but mundane nature with built structures present. Students rated settings that lacked views of real or simulated nature least restorative. The findings suggest that large nature murals in indoor settings used for study breaks may provide attentionally fatigued students with opportunities for restoration when views of nature are unavailable or limited in restorative potential. 相似文献