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541.
542.
Stephen D. Preston Richard B. Alexander David M. Wolock 《Journal of the American Water Resources Association》2011,47(5):887-890
Preston, Stephen D., Richard B. Alexander, and David M. Wolock, 2011. SPARROW Modeling to Understand Water‐Quality Conditions in Major Regions of the United States: A Featured Collection Introduction. Journal of the American Water Resources Association (JAWRA) 47(5):887‐890. DOI: 10.1111/j.1752‐1688.2011.00585.x 相似文献
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Cap and trade programs have considerable heterogeneity in permit validity and compliance timing. For example, permits have different validities across time (e.g., banking, borrowing, and seasons) and space (e.g., zonal restrictions), and compliance timing can be annual, in overlapping cycles, or in multi-year periods. We discuss nine prominent cap and trade programs along these dimensions and construct a general model of permit validity and compliance timing. We derive sufficient conditions under which abatement is invariant to compliance timing, i.e., compliance timing cannot smooth abatement cost shocks. Under these conditions, (i) expected compliance costs are invariant, (ii) the variance of compliance costs increases with the delayed compliance, (iii) equilibrium prices may not be unique, and (iv) the delayed compliance equilibrium may rely on “degenerate” prices not determined by marginal abatement costs. We demonstrate the model's broad applicability by illustrating different types of temporal permit validity. 相似文献
546.
Stephen C. Votier W. James Grecian Samantha Patrick Jason Newton 《Marine Biology》2011,158(2):355-362
Seabird populations contain large numbers of immatures––in some instances comprising >50% of the fully grown adults in the
population. These birds are significant components of marine food webs and may contribute to compensatory recruitment and
dispersal, but remain severely understudied. Here, we use GPS-PTTs, radio-tracking and analysis of stable carbon (δ13C) and nitrogen (δ15N) isotopes to investigate the movements and foraging ecology of immature seabirds. Our study focussed on immature northern
gannets Morus bassanus aged 2–4 attending non-breeding aggregations alongside a large breeding colony. GPS-PTT tracking of five birds revealed that
immatures have the ability to disperse widely during the breeding season, with some individuals potentially prospecting at
other colonies. Overall, however, immatures were faithful to the colony of capture. During returns to the focal colony, immatures
acted as central place foragers, conducted looping and commuting flights, and analysis of the variance in first-passage time
revealed evidence of area-restricted search (ARS) behaviour. In addition, stable carbon (δ13C) and nitrogen (δ15N) isotope analyses indicate that immatures were isotopically segregated from breeders. Our findings provide insights into
the foraging, prospecting and dispersal behaviour of immature seabirds, which may have important implications for understanding
seabird ecology and conservation. 相似文献
547.
Strong genetic change over short spatial scales is surprising among marine species with high dispersal potential. Concordant
breaks among several species signals a role for geographic barriers to dispersal. Along the coast of California, such breaks
have not been seen across the biogeographic barrier of Point Conception, but other potential geographic boundaries have been
surveyed less often. We tested for strong-population structure in 11 species of Sebastes sampled across two regions containing potential dispersal barriers, and conducted a meta-analysis including four additional
species. We show two strong breaks north of Monterey Bay, spanning an oceanographic gradient and an upwelling jet. Moderate
genetic structure is just as common in the north as it is in the south, across the biogeographic break at Point Conception.
Gene flow is generally higher among deep-water species, but these conclusions are confounded by phylogeny. Species in the
subgenus Sebastosomus have higher structure than those in the subgenus Pteropodus, despite having larvae with longer pelagic phases. Differences in settlement behavior in the face of ocean currents might
help explain these differences. Across similar species across the same coastal environment, we document a wide variety of
patterns in gene flow, suggesting that interaction of individual species traits such as settlement behavior with environmental
factors such as oceanography can strongly impact population structure. 相似文献
548.
Kerstin K. Zander Stephen T. Garnett Anna Straton 《Journal of environmental management》2010,91(12):2519-2528
Australia’s system of tropical rivers constitutes one of the largest and least changed drainage networks in the world. However increasing demand for water in parts of Australia, along with ongoing drought, is driving pressure to develop these rivers. This paper reports the results of a choice experiment (CE) to assess the benefits of different management strategies for three tropical rivers in northern Australia: the Daly, Mitchell and Fitzroy Rivers. The CE was carried out using a survey mailed to Australian urban populations. The results showed that 90% of Australians were willing to pay a once-off payment for the management of tropical rivers. Respondents who had visited or lived near the rivers were willing to pay more for cultural, recreational and environmental services than those who had not. Respondents classed as ‘developers’, who made up only 4% of the 684 respondents, considered a substantial income from irrigated agriculture as important. Unlike ‘environmentalists’ and ‘neutrals’, ‘developers’ were unwilling to pay for high quality recreational fishing or for having floodplains in good environmental condition. All groups, however, were willing to pay for high cultural values. 相似文献
549.
River inflow, estuarine salinity, and Carolina wolfberry fruit abundance: linking abiotic drivers to Whooping Crane food 总被引:1,自引:0,他引:1
Jeffrey R. Wozniak Todd M. Swannack Rachel Butzler Christopher Llewellyn Stephen E. Davis III 《Journal of Coastal Conservation》2012,16(3):345-354
The supply of freshwater to estuarine ecosystems is a critical factor in maintaining the overall health and organization of coastal marshes. Specifically along the Texas Gulf coast, the coupled effects of decreased freshwater inflows to the estuary and natural processes (e.g., precipitation, wind, and tides) can exert significant salt-stress on coastal marsh vegetation. In this project we sought to quantitatively link the inflow of freshwater to the estuary (San Antonio Bay) with Aransas National Wildlife Refuge (ANWR) coastal marsh salinity and assess the influence of salinity and inundation on Carolina wolfberry (Lycium carolinianum Walt.) phenology (leaf and fruit abundance). The Carolina wolfberry is one of the more common high marsh plant species found at ANWR and has been shown to be a key food source for endangered Whooping Cranes which inhabit the coastal marshes of the ANWR each fall/winter. Results from our study show that periods of decreased freshwater inflows to the estuary correlated with increased marsh salinity at the ANWR. Wolfberry plants at ANWR marsh sites displayed increased fruit abundance during years which had lower mean summer time salinity (June, July, and August) in San Antonio Bay; conversely, during years of increased bay salinity during the same summertime months, wolfberry plants showed decreased fruit abundance. Through the continued validation of the relationship between inflows and coastal marsh salinity, we hope to provide additional insight into how wolfberry phenology varies inter-annually across both salinity and inundation regimes and how freshwater inflows may affect food availability for the endangered Whooping Crane. 相似文献
550.
The Campus Demotechnic Index (CDI) was modified from the Demotechnic Index (D-Index) to serve as an index of energy use for
US colleges and universities. CDI values were calculated by assessing the total campus energy used for the built and mobile
environments against energy required to meet the basal metabolic demand of the total campus population. Like the D-Index,
the CDI measured the scalar quantity of energy used relative to the quantity of energy required for simple survival on a per
capita basis, thus providing a rational metric for comparison among institutions. For the interval 2000–2005, CDI was calculated
for 64 US higher education institutions and compared using maximum, minimum, mean and median CDI values, total gigajoules
used, campus population, and consumption-adjusted population. Wilcoxon signed rank test results compared pair-by-pair differences
of ranked CDI values from 2000 to 2005 to determine whether CDI values were significantly increasing or decreasing over time.
In general, CDI values increased over time, but increases over the 6-year interval were only significantly higher in 8 of
30 two-year comparisons; in 2005, CDI values ranged from 1.1 to 56.3 (mean = 11.9, median = 8.2, n = 64), whereas in 2000, CDI values ranged from 2.0 to 53.0 (mean = 12.6, median = 9.1, n = 22). Results suggest that the CDI may serve as a useful metric for tracking campus energy efficiency over time as well
as a means of comparison of energy use among institutions. 相似文献