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961.
Increasingly, performance measurement is being used to hold federal agencies accountable, represent environmental progress, and evaluate the effectiveness of environmental programs. The need to track measurable outputs has created a tendency to present programmatic progress solely by quantifiable data, despite the inherent complexity of natural resource management. Wetlands and fire management programs are two specific environmental arenas that have come to overemphasize the tracking of acreage numbers to validate existing policy direction. In both of these arenas, we find the definition and categorization of "countable" acres to be inconsistent and unreliable. We explore this systemic flaw for both wetlands and fire programs and describe its implications for environmental policy and natural resource management more broadly. We conclude with recommendations for improved performance measurement in these arenas.  相似文献   
962.
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   
963.
Escherichia coli can persist in streambed sediments and influence water quality monitoring programs through their resuspension into overlying waters. This study examined the spatial patterns in E. coli concentration and population structure within streambed morphological features during baseflow and following stormflow to inform sampling strategies for representative characterization of E. coli populations within a stream reach. E. coli concentrations in bed sediments were significantly different (p?=?0.002) among monitoring sites during baseflow, and significant interactive effects (p?=?0.002) occurred among monitoring sites and morphological features following stormflow. Least absolute shrinkage and selection operator (LASSO) regression revealed that water velocity and effective particle size (D 10) explained E. coli concentration during baseflow, whereas sediment organic carbon, water velocity and median particle diameter (D 50) were important explanatory variables following stormflow. Principle Coordinate Analysis illustrated the site-scale differences in sediment E. coli populations between disconnected stream segments. Also, E. coli populations were similar among depositional features within a reach, but differed in relation to high velocity features (e.g., riffles). Canonical correspondence analysis resolved that E. coli population structure was primarily explained by spatial (26.9–31.7 %) over environmental variables (9.2–13.1 %). Spatial autocorrelation existed among monitoring sites and morphological features for both sampling events, and gradients in mean particle diameter and water velocity influenced E. coli population structure for the baseflow and stormflow sampling events, respectively. Representative characterization of streambed E. coli requires sampling of depositional and high velocity environments to accommodate strain selectivity among these features owing to sediment and water velocity heterogeneity.  相似文献   
964.
Studies on toxicities and tolerances of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in the brown alga Isochrysis galbana and in the green-lipped mussel Perna viridis were conducted by short-term bioassays using endpoints growth production and mortality, respectively. The 5-day EC(50) and 24-h LC(50) of these heavy metals were determined in the brown alga and mussel, respectively. The EC(50) values calculated for the alga were 0.74 mg/l for Cd, 0.91 mg/l for Cu, 1.40 mg/l for Pb and 0.60 mg/l for Zn. The LC(50) values for the mussels were 1.53 mg/l for Cd, 0.25 mg/l for Cu, 4.12 mg/l for Pb and 3.20 mg/l for Zn. These LC(50) values were within the concentration ranges as reported by other authors who used P. viridis as the test organism. Based on these EC(50) and LC(50) values, the alga was most sensitive to Zn, followed by Cd, Cu and Pb while the mussel was most sensitive to Cu, followed by Cd, Zn and Pb. Differences in the trophic levels, metal handling strategies, biology and ecology of the primary producer (brown alga) and the primary consumer (mussel) are believed to be the plausible causes for the different toxicities and tolerances of the metals studied.  相似文献   
965.
966.
DIMBOA (3,4-dihydro-2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one), a major benzoxazinone of Poaceae plants, was isolated and purified from corn seedlings. The effect of isolated and purified DIMBOA on the degradation of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], and its toxic breakdown products, desethylatrazine [2-chloro-4-amino-6-(isopropylamino)-s-triazine; DEA] and desisopropylatrazine [2-chloro-4-(ethylamino)-6-amino-s-triazine; DIA], was studied in the absence of plants using batch experiments, while the effect of corn root exudates on these compounds was determined in hydroponic experiments. Degradation experiments were performed in the presence and absence of 50 microM, 1 mM, or 5 mM DIMBOA resulting in ratios of DIMBOA to pesticide of 1:1, 20:1, and 100:1. We observed a 100% degradation of atrazine to hydroxyatrazine within 48 h at a ratio of DIMBOA to atrazine of 100:1. DIMBOA had the largest effect on atrazine, while it was about three times less effective on DEA and DIA. Corn (Zea mays L. cv. LG 2185) was exposed to 10 mg L(-1) of either atrazine, DEA, or DIA for 11 d in a growth chamber experiment. Up to 4.3 micromol L(-1) d(-1) of hydroxyatrazine were formed in the nutrient solutions by plants exposed to atrazine, while the formation of hydroxylated metabolites from plants exposed to DEA and DIA was smaller and also delayed. The formation of hydroxylated metabolites increased in the solution with plant age in all atrazine, DEA, and DIA treatments. HMBOA (3,4-dihydro-2-hydroxy-7-methoxy-2H-1,4-benzoxazin-3-one), the lactam precursor of DIMBOA, and a tentatively identified derivative of MBOA (2,3-dihydro-6-methoxy-benzoxazol-2-one) were detected in the corn root exudates. Mass balance calculations revealed that up to 30% of the disappearance of atrazine and DEA, and up to 10% of DIA removal from the solution medium in our study could be explained by the formation of hydroxylated metabolites in the solution itself. Our results show that higher plants such as corn have the potential to promote the hydrolysis of triazine residues in soils by exudation of benzoxazinones.  相似文献   
967.
Environmental pollution and degradation of ecosystems considerably affect the natural resources. The Turkish Government is aware of the importance of the preservation of natural ecology and thereby the environmental conservation of many species in their natural habitat. This paper provides critical assessments of the problems and possible solutions in the identification, implementation and management of the Specially Protected Areas (SPAs) system by giving basic information about stakeholders and their responsibilities that currently offer nature conservation in Turkey. The goals of the article are to analyze how the SPAs interface with the local people, especially the villagers who have dwelt there before SPA designation and how people-SPA conflicts resolved; to show how effective the SPA conservation objectives have been; to outline the significance of informing and empowering people in nature conservation for the protected area management and to show the importance of planning at all levels during protection of the natural, archeological and cultural values of the SPAs.  相似文献   
968.
Building a community that is resilient to disasters has become one of the main goals of disaster management. Communities that are more disaster resilient often experience less impact from the disaster and reduced recovery periods afterwards. This study develops a methodology for constructing a set of indicators measuring Community Disaster Resilience Index (CDRI) in terms of human, social, economic, environmental, and institutional factors. In this study, the degree of community resilience to natural disasters was measured for 229 local municipalities in Korea, followed by an examination of the relationship between the aggregated CDRI and disaster losses, using an ordinary least squares (OLS) regression method and a geographically weighted regression (GWR) method. Identifying the extent of community resilience to natural disasters would provide emergency managers and decision-makers with strategic directions for improving local communities' resilience to natural disasters while reducing the negative impacts of disasters.  相似文献   
969.
The practice of vermiculture is at least a century old but it is now being revived worldwide with diverse ecological objectives such as waste management, soil detoxification and regeneration and sustainable agriculture. Earthworms act in the soil as aerators, grinders, crushers, chemical degraders and biological stimulators. They secrete enzymes, proteases, lipases, amylases, cellulases and chitinases which bring about rapid biochemical conversion of the cellulosic and the proteinaceous materials in the variety of organic wastes which originate from homes, gardens, dairies and farms. The process is odour free because earthworms release coelomic fluids in the decaying waste biomass which has anti-bacterial properties which kills pathogens. The species used in India were Indian blue (Perionyx excavatus), African night crawler (Eudrilus euginae) and the Tiger worm (Elsinia foetida). E. foetida was used in Australia. E. euginae was found to have higher feeding, growth and biodegradation capacity compared to other two species.Earthworm action was shown to enhance natural biodegradation and decomposition of wastes (60–80 percent under optimum conditions), thus significantly reducing the composting time by several weeks. Within 5 to 6 weeks, 95–100 percent degradation of all cellulosic materials was achieved. Even hard fruit and egg shells and bones can be degraded, although these may take longer.  相似文献   
970.
Uncertainty in future water supplies for the Phoenix Metropolitan Area (Phoenix) are exacerbated by the near certainty of increased, future water demands; water demand may increase eightfold or more by 2030 for some communities. We developed a provider-based water management and planning model for Phoenix termed WaterSim 4.0. The model combines a FORTRAN library with Microsoft C# to simulate the spatial and temporal dynamics of current and projected future water supply and demand as influenced by population demographics, climatic uncertainty, and groundwater availability. This paper describes model development and rationale. Water providers receive surface water, groundwater, or both depending on their portfolio. Runoff from two riverine systems supplies surface water to Phoenix while three alluvial layers that underlie the area provide groundwater. Water demand was estimated using two approaches. One approach used residential density, population projections, water duties, and acreage. A second approach used per capita water consumption and separate population growth estimates. Simulated estimates of initial groundwater for each provider were obtained as outputs from the Arizona Department of Water Resources (ADWR) Salt River Valley groundwater flow model (GFM). We compared simulated estimates of water storage with empirical estimates for modeled reservoirs as a test of model performance. In simulations we modified runoff by 80%-110% of the historical estimates, in 5% intervals, to examine provider-specific responses to altered surface water availability for 33 large water providers over a 25-year period (2010-2035). Two metrics were used to differentiate their response: (1) we examined groundwater reliance (GWR; that proportion of a providers' portfolio dependent upon groundwater) from the runoff sensitivity analysis, and (2) we used 100% of the historical runoff simulations to examine the cumulative groundwater withdrawals for each provider. Four groups of water providers were identified, and discussed. Water portfolios most reliant on Colorado River water may be most sensitive to potential reductions in surface water supplies. Groundwater depletions were greatest for communities who were either 100% dependent upon groundwater (urban periphery), or nearly so, coupled with high water demand projections. On-going model development includes linking WaterSim 4.0 to the GFM in order to more precisely model provider-specific estimates of groundwater, and provider-based policy options that will enable "what-if" scenarios to examine policy trade-offs and long-term sustainability of water portfolios.  相似文献   
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