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101.
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Brian Buchanan Zachary M. Easton Rebecca Schneider M. Todd Walter 《Journal of the American Water Resources Association》2012,48(1):43-60
Buchanan, Brian, Zachary M. Easton, Rebecca Schneider, and M. Todd Walter, 2011. Incorporating Variable Source Area Hydrology Into a Spatially Distributed Direct Runoff Model. Journal of the American Water Resources Association (JAWRA) 48(1): 43‐60. DOI: 10.1111/j.1752‐1688.2011.00594.x Abstract: Few hydrologic models simulate both variable source area (VSA) hydrology, and runoff‐routing at high enough spatial resolutions to capture fine‐scale hydrologic pathways connecting VSA to the stream network. This paper describes a geographic information system‐based operational model that simulates the spatio‐temporal dynamics of VSA runoff generation and distributed runoff‐routing, including through complex artificial drainage networks. The model combines the Natural Resource Conservation Service’s Curve Number (CN) equation for estimating storm runoff with the topographic index concept for predicting the locations of VSA and a runoff‐routing algorithm into a new spatially distributed direct hydrograph (SDDH) model (SDDH‐VSA). Using a small agricultural watershed in central New York, SDDH‐VSA results were compared to those from a SDDH model using the traditional land use assumptions for the CN (SDDH‐CN). The SDDH‐VSA model generally agreed better with observed discharge than the SDDH‐CN model (average, Nash‐Sutcliffe efficiency of 0.69 vs. 0.58, respectively) and resulted in more realistic spatial patterns of runoff‐generating areas. The SDDH approach did not correctly capture the timing of runoff from small storms in dry periods. Despite this type of limitation, SDDH‐VSA extends the applicability of the SDDH technique to VSA conditions, providing a basis for new tools to help identify critical management areas and assess water quality risks due to landscape alterations. 相似文献
103.
Kölliker R Bassin S Schneider D Widmer F Fuhrer J 《Environmental pollution (Barking, Essex : 1987)》2008,152(2):380-386
The genetic composition and diversity of Plantago lanceolata L. populations were analysed using amplified fragment length polymorphism (AFLP) as well as simple sequence repeat (SSR) markers to test for differences in an old semi-natural grassland after five years of treatment with ambient or elevated ozone (O3) using a free-air fumigation system. Genetic diversity in populations exposed to elevated O3 was slightly higher than in populations sampled from control plots. This effect was significant for AFLP-based measures of diversity and for SSR markers based on observed heterozygosity. Also, a small but significant difference in genetic composition between O3 treatments was detected by analysis of molecular variance and redundancy analysis. The results show that micro-evolutionary processes could take place in response to long-term elevated O3 exposure in highly diverse populations of outbreeding plant species. 相似文献
104.
Coupled human and natural systems 总被引:18,自引:0,他引:18
Liu J Dietz T Carpenter SR Folke C Alberti M Redman CL Schneider SH Ostrom E Pell AN Lubchenco J Taylor WW Ouyang Z Deadman P Kratz T Provencher W 《Ambio》2007,36(8):639-649
Humans have continuously interacted with natural systems, resulting in the formation and development of coupled human and natural systems (CHANS). Recent studies reveal the complexity of organizational, spatial, and temporal couplings of CHANS. These couplings have evolved from direct to more indirect interactions, from adjacent to more distant linkages, from local to global scales, and from simple to complex patterns and processes. Untangling complexities, such as reciprocal effects and emergent properties, can lead to novel scientific discoveries and is essential to developing effective policies for ecological and socioeconomic sustainability. Opportunities for truly integrating various disciplines are emerging to address fundamental questions about CHANS and meet society's unprecedented challenges. 相似文献
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/ Protected area management is increasingly important throughout the world, particularly in less developed countries and arid regions. The Middle East, includingJordan, has important and unique resources due to its varied topography and climate. In Jordan, the protected areas are privately, rather than publicly, managed, and this provides for a unique and somewhat challenging management effort. The purpose of this paper is to review the establishment and administration of Jordan's protected areas with particular emphasis on the challenges of multiple administrative and legislative layers, departmental working relationships, and a paucity of funding. Interviews with government and nongovernmental experts in Jordan, coupled with a review of pertinent academic and planning literature, served as the information base for this study. Despite new legislative and administrative initiatives, results reveal important and continuing challenges for Jordan. Recommendations include completion of protected area inventories, government wide institutional strengthening, partnering with organizations and the public, as well as legislative reexamination. 相似文献
108.
A project to characterize the radionuclide and chemical components in natural spring waters in the vicinity of Saratoga Springs, New York (USA) has been completed. As a result of the measured radionuclide and chemical content, eight springs were labeled as mineral waters, whereas three springs contained very low concentrations of these components. The mineral waters were highly enriched in alkaline and alkaline-earth elements, as well as chloride ions. Three isotopes of radium ((224)Ra, (226)Ra, (228)Ra) were detected in the mineral waters and reached concentrations of 1, 20, and 2 Bq/L, respectively. Overall, the (226)Ra isotope constituted about 80% of the total radioactivity measured in the water samples. Dissolved uranium concentrations in the mineral waters were very low (mean approximately 50 mBq/L). 相似文献
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Photographic and trap data obtained from the eastern North Atlantic Ocean in 1981 and 1978, respectively, have been combined to document the response of abyssal lysianassid amphipods to large food falls, and the predation on these amphipods by the fish Paraliparis bathybius. The use of a new camera/current meter system has demonstrated that overall numbers of amphipods and presence of fish were related to tidal currents. Species of Paralicella and Orchomene were the most abundant amphipods, and occurred in peak numbers during periods of low current velocity. Variation in abundance of Eurythenes gryllus, a larger species, which occurred in smaller numbers, was apparently not related to tidal currents. Paraliparis bathybius were present only during flood tides. 相似文献