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1.
Gregory F. Mclsaac Matthew B. Short George Groschen Paul Terrio 《Journal of the American Water Resources Association》2004,40(2):443-459
ABSTRACT: Long term data on surface water quality can sometimes be assembled by combining data collected by different agencies at different times and assuming that between agency differences in data quality are insignificant. The objective of this paper was to assess the quality of riverine nitrate (NO3) concentrations in Illinois measured and reported by four agencies from 1967 to 1974 by comparing median values for similar sampling locations and periods. A total of 17 river reaches were identified for which two agencies reported NO3 concentrations during similar periods. Nonparametric comparison of median values and analysis of covariance with discharge as a covariant produced similar results. Nitrate concentrations reported by the U.S. Geological Survey (USGS) from 1967 to 1971 were not statistically (P > 0.05) different from values reported by the Illinois State Water Survey (ISWS) for two of three river reaches. Additionally, NO3 concentrations reported by USGS from 1972 to 1974 were not statistically different than concentrations reported by the Illinois Environmental Protection Agency (IEPA) for four of five river reaches. From 1969 to 1971, NO3 concentrations reported by the Illinois Department of Public Heath and the Illinois Environmental Protection Agency (IDPH/IEPA) were less than one‐fourth the magnitude of values reported by ISWS. The median NO3 concentrations measured by the Central Illinois Public Service (CIPS) were significantly greater than those measured by USGS and IDPH/IEPA in the three comparable sampling locations. The use of NO3 concentrations measured by CIPS and IDPH/IEPA prior to 1972 is not recommended. 相似文献
2.
Carey PD Short C Morris C Hunt J Priscott A Davis M Finch C Curry N Little W Winter M Parkin A Firbank LG 《Journal of environmental management》2003,69(1):71-91
With an increasing amount of public funds being spent on agri-environmental schemes effective methods have to be developed to evaluate them. As many schemes have multiple objectives there is a need for a multi-disciplinary approach to any evaluation. A method was developed to assess the degree to which ecological, landscape, historical and access objectives for the Countryside Stewardship Scheme (CSS) in England have been met. The method used a sample of 484 agreements for which data were collected from surveys, a desk study and an interview with the agreement holder. These data were then evaluated by an expert team of an ecologist, landscape architect, landscape historian, and a social scientist specializing in rural affairs. The team were subsequently brought together with a Chair to discuss their findings for each agreement, allocating scores for each of five criteria: agreement negotiation; appropriateness, environmental effectiveness, compliance and side effects. The additionality that each agreement was likely to provide was also assessed. The results of this process suggest that in the majority of cases the CSS agreements should maintain or enhance the environment in terms of ecology, landscape, and landscape history and increase public enjoyment of the countryside. Thirty-six percent of agreements showed high additionality and 38% medium additionality which demonstrates that the CSS is likely to provide a benefit to society. Agreement negotiation, predicted environmental effectiveness and predicted compliance all improved significantly over the period 1996-98. Recommendations made from this project have been implemented by the Government department to improve the CSS. The multi-disciplinary method was successful and, with further development, could be used for assessment of any agri-environment scheme, or potentially any conservation project or broader 'rural development' scheme encompassing environmental, economic and social objectives. A key to success is the need for the criteria to be tailored for the project concerned and clearly established at the beginning. 相似文献
3.
The otoliths of the King George whiting Sillaginodes punctata were assessed for their usefulness in adult-ageing. Whole, transverse-sectioned and broken/burnt sagittae displayed alternating
opaque and translucent zones. Some small whole otoliths contained accessory areas of pigment, whilst large otoliths were too
thick to transmit light, resulting in ambiguous counts in each case. Both marginal-increment analysis and treatment of fish
with tetracycline demonstrated that the first three opaque zones formed annually, the first during the spring/summer of the
second year of life, and the second and third in each subsequent spring. Otolith thickness increased linearly with the completion
of each new opaque/translucent zone. An ageing protocol based on whole otoliths, supplemented with the breaking/burning of
ambiguous otoliths is recommended. An algorithm for calculating age in months from otolith counts based on a fixed birth-date
of the mid-point of the spawning season is presented.
Received: 18 August 1997 / Accepted: 15 October 1997 相似文献
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5.
Natural levels of210Pb:226Ra in otoliths of orange roughy,Hoplostethus atlanticus, from south-east Australian waters, were measured to determine fish ages radiometrically. Up to maturity, radiometric age estimates were consistent with a single constant otolith growth rate. Radiometric ages for juveniles were comparable with, but greater than, those obtained in a recent, validated New Zealand study which employed counts of annuli on the surface of otoliths. Beyond maturity, radiometric ages were obtained by modelling with an otolith growth rate set at 45% of the juvenile rate. Radiometric ageing confirms that orange roughy is very slow-growing, with an age at maturity (32 cm standard length, SL) of ~ 32 yr, and is very long-lived, with fish 38 to 40 cm being 77 to 149 yr old. These results have important implications for the management of the fishery. 相似文献
6.
Numerous seagrass species growing in high-light environments develop red coloration in otherwise green leaves, yet the ecophysiology
of leaf reddening in seagrasses is poorly understood. To increase our understanding of the process of leaf reddening in Thalassia testudinum found in the lower Florida Keys (USA), we identified the molecules responsible for red coloration in leaves and compared
physiological, morphological, and growth attributes of entirely red-leafed shoots to entirely green-leafed shoots. We determined
that four anthocyanin molecules are responsible for red coloration in leaves. In addition, we found that red leaves had higher
concentrations of photoprotective pigments (anthocyanins and UV-absorbing compounds), higher effective quantum yields (ΔF/F
m′) at midday, and were shorter, narrower, and weighed less than green leaves. No significant difference in growth rates was
observed between red- and green-leafed shoots, but patches of red-leafed shoots had shorter canopy heights and smaller LAI
compared to patches of green-leafed shoots. Our results demonstrate that leaf reddening in T. testudinum is caused by high concentrations of anthocyanins, is associated with physiological and morphological attributes, and acts
as a sunscreen since red leaves were able to maintain high effective quantum yields at high light intensities. 相似文献
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8.
Goldstein RM Carlisle DM Meador MR Short TM 《Environmental monitoring and assessment》2007,130(1-3):495-510
The environmental setting (e.g., climate, topography, geology) and land use affect stream physical characteristics singly
and cumulatively. At broad geographic scales, we determined the importance of environmental setting and land use in explaining
variation in stream physical characteristics. We hypothesized that as the spatial scale decreased from national to regional,
land use would explain more of the variation in stream physical characteristics because environmental settings become more
homogeneous. At a national scale, stepwise linear regression indicated that environmental setting was more important in explaining
variability in stream physical characteristics. Although statistically discernible, the amount of variation explained by land
use was not remarkable due to low partial correlations. At level II ecoregion spatial scales (southeastern USA plains, central
USA plains, and a combination of the western Cordillera and the western interior basins and ranges), environmental setting
variables were again more important predictors of stream physical characteristics, however, as the spatial scale decreased
from national to regional, the portion of variability in stream physical characteristics explained by basin land use increased.
Development of stream habitat indicators of land use will depend upon an understanding of relations between stream physical
characteristics and environmental factors at multiple spatial scales. Smaller spatial scales will be necessary to reduce the
confounding effects of variable environmental settings before the effects of land use can be reliably assessed. 相似文献
9.
Occurrence of tri-n-butyltin-caused imposex in the North Pacific marine snail Nucella lima in Auke Bay,Alaska 总被引:3,自引:0,他引:3
Like female dog whelks (Nucella lapillus) in the Atlantic Ocean, females of the Pacific gastropod N. lima respond to low concentrations of tri-n-butyltin (TBT) by growing a penis and vas deferens. This condition, termed imposex, was found to occur in N. lima collected from August 1987 to May 1988 along a TBT pollution gradient associated with a marina in Auke Bay, Alaska. The suite of symptoms characteristic of imposex in N. lima was slightly different than in N. lapillus. Imposex, as measured by relative penis size (RPS) of females to males, increased from 0.0 to 34.27 along this gradient and as measured by vas deferens sequenceindex (VDS) increased similarly from 0.0 to 4.29. Concentrations of TBT in N. lima increased from below detection limits (about 0.010 g Sn g-1 dry tissue wt) to 0.065 g Sn g-1 dry tissue wt along the gradient. The gradient was determined by measuring TBT in whole-body tissues of bay mussels (Mytilus edulis). Concentrations of TBT in mussels increased from below detection limits to 0.833 g Sn g-1 dry tissue wt in mussels from within the marina that was the major local source of TBT. Imposex, tissue TBT burden, and position along a TBT pollution gradient are significantly correlated (P<0.01) in N. lima. TBT was tested as a causative agent for imposex by exposing snails at a distant control site to TBT paint. After 1 mo exposure, 33% of the females grew a penis ranging in size from 0.2 to 0.8 mm. Our results generally corroborate those found for N. lapillus and indicate that imposex in N. lima is caused by environmental TBT exposure. We suggest that the RPS in the genus Nucella may be useful in monitoring TBT in coastal waters worldwide. 相似文献
10.
Christopher Short Michael Winter 《Journal of Environmental Planning and Management》1999,42(5):613-630
This paper examines the current governance of common land with the intention of updating a story last examined in detail in studies in the late 1980s. In addition, the paper draws on recent conceptualizations of stakeholders and governance. A brief history of common land shows that governance systems are highly localized and dependent on custom and practice. Such a dependence suggests the need for governance which is based on the incorporation of stakeholders using consensus building approaches. The paper suggests that local governance systems are crucial to the successful implementation of sustainable management practices but that this may be overlooked by land managers and policy makers. Consequently, comprehensive national legislation for common land is not a viable option but legislation can play a valuable role in particular circumstances. The need to give further consideration to the role of legislation and an appropriate policy framework for commons within the context of stakeholder governance is particularly important given the significance of common land for agriculture, nature conservation, landscape, heritage and recreation across England and Wales. 相似文献