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201.
202.
ABSTRACT: The lower 4 miles of the Red River, a tributary of the Rio Grande in northern New Mexico, was designated as one of the “instant” components of the National Wild and Scenic River System in 1968. The Bureau of Land Management (BLM), as the managing agency of the wild and scenic river, was a participant in a general water rights adjudication of the Red River stream system. The BLM sought a federal reserved water right and asserted a claim to the instream flows necessary to protect and maintain the values of the river. Instream flows are not recognized under New Mexico water law. Instream flow requirements were determined by several methods to quantify the claims made by the United States for a federal reserved water right under the Wild and Scenic Rivers Act. The scenic (aesthetic), recreational, and fish and wildlife values are the purposes for which instream flow requirements were claimed. Since water quality is related to these values, instream flows for waste transport and protection of water quality were also included in the claim. The U.S. Fish and Wildlife Service's Instream Flow Incremental Methodology was used to quantify the relationship between various flow regimes and fish habitat. Experience in this litigation indicates the importance of using state-of-the-art methodologies in quantifying instream flow claims. The incremental methodology held up well under technical and legal scrutiny and is an example of the latest methodology that was applied successfully in an adjudication. On February 23, 1984, the parties involved in the adjudication entered a precedential stipulation recognizing a federal reserved right to instream flows for the Red River component of the National Wild and Scenic River System.  相似文献   
203.
Oregon state law requires each county in the state to identify agricultural land and enact policies and regulations to protect agricultural land use. State guidelines encourage the preservation of large parcels of agricultural land and discourage partitioning of agricultural land and construction of nonfarm dwellings in agricultural areas. A land evaluation and site assessment (LESA) system was developed in Linn County to aid in the identification of agricultural land and provide assistance to decision makers concerning the relative merits of requests to partition existing parcels of ricultural land and introduce nonagricultural uses.Land evaluation was determined by calculating soil potential ratings for each agricultural soil in the county based on the soil potentials for winter wheat, annual ryegrass, permanent pasture, and irrigated sweet corn. Soil potential ratings were expressed on a scale of 0 to 150 points. The land evaluation score for a parcel consists of the weighted average soil potential rating for all of the soils in the parcel, weighted by the percentage of each soil present in the parcel.Site assessment was based on the size of a parcel and on the amount of existing conflict between agricultural and nonagricultural uses, particularly rural residential uses, both adjacent to and in the vicinity of a parcel. Parcel size refers to both size in relation to a typical field and size in relation to a typical farm unit. Conflict takes into account the number of nonfarm dwellings within 1/4 mile (0.4 km) of a parcel, the amount of the perimeter that adjoins conflicting land uses, and the residential density adjacent to the parcel. Empirical scales were derived for assigning points to each of the site assessment factors. Both parcel size and conflict were worth 75 points in the model. For parcel size, 45 points were allocated to field size and 30 points to farm-unit size. For conflict, 30 points were allocated to nonfarm dwellings within 1/4 mile and 45 points to perimeter conflicts.The LESA model was validated by testing on 23 parcels in Linn County for which requests to partition and/or convert to nonagricultural uses had been received by the County Planning Department. This testing was an essential part of the development process, as it pointed out inconsistencies and errors in the model and allowed continuous adjustment of factors and point scales. The results of application of the final model to three of the case studies are presented to illustrate the concepts.Three possible uses of the information generated by the LESA system include determining the relative agricultural value of a parcel, determining grades of agricultural land suitability, and determining the impacts of changing land use on other parcels in the vicinity. Relative agricultural value is a direct outcome of application of the evaluation criteria in the LESA model. Good, marginal, and nonagricultural grades of agricultural suitability were determined by examining the data from all 23 test cases and establishing threshold point values for soil quality, conflict, parcel size, and total LESA score. Impact analyses were not done in this study, but could be achieved by calculating LESA scores for all parcels possibly affected by a land-use change both before and after a proposed change. All three applications fall short of making a specific land-use decision, but they do provide information that should be of value to the local jurisdiction charged with making such decisions.  相似文献   
204.
ABSTRACT: The hypothesis of this paper is that regulatory systems for the control of effluent released to the environment can be, if improperly designed, inadequate for both the establishment of effective pollution control policy and the assessment of the biological significance of violations. This inadequacy may stem from several factors: first, the use of single point standards which delineate the boundary between legally acceptable and unacceptable pollutant discharges; and second, the existence of significant weaknesses in the frequency and design of monitoring programs. In order to be effective, pollution standards must reflect the impact of pollutants on the ecosystem. To achieve this goal, three critical pieces of information are required: measurement of ambient levels of released pollutants, frequency distributions derived from these data, and estimates of biological damage functions. Illustrating the above three requirements with data drawn from research in British Columbia, the authors recommended a restructuring of environmental policy to provide regulatory agencies with an effective mechanism for the analysis and control of environmental degradation.  相似文献   
205.
206.
We conducted experiments designed to examine the distribution of foraging honey bees (Apis mellifera) in suburban environments with rich floras and to compare spatial patterns of foraging sites used by colonies located in the same environment. The patterns we observed in resource visitation suggest a reduced role of the recruitment system as part of the overall colony foraging strategy in habitats with abundant, small patches of flowers. We simultaneously sampled recruitment dances of bees inside observation hives in two colonies over 4 days in Miami, Florida (1989) and from two other colonies over five days in Riverside, California (1991). Information encoded in the dance was used to determine the distance and direction that bees flew from the hive for pollen and nectar and to construct foraging maps for each colony. The foraging maps showed that bees from the two colonies in each location usually foraged at different sites, but occasionally they visited the same patches of flowers. Each colony shifted foraging effort among sites on different days. In both locations, the mean flight distances differed between colonies and among days within colonies. The flight distances observed in our study are generally shorter than those reported in a similar study conducted in a temperate deciduous forest where resources were less dense and floral patches were smaller.  相似文献   
207.
A sediment core from a lake downwind of the Rocky Flats Plant, where nuclear weapons components are produced, was used to reconstruct a time pattern of off-site plutonium deposition. Core sections were dated by analyses of 137Cs, 239,240Pu, 238Pu, and 241Am fallout from nuclear testing and 238Pu fallout from a satellite failure. A peak in transuranic concentrations occurred in late 1969 which was attributable to the Plant. This was confirmed by mass isotopic analysis of plutonium isotopes in selected core segments where the global fallout and Plant contributions could be differentiated. The 18 nCi 239,240Pu per m2 from the Plant that had accumulated in the sediment is reasonable when compared to soil analyses.  相似文献   
208.
There are many examples in the developing countries (DCs) of environmental standards being set at high levels that cannot possibly be met in the prevailing economic conditions. Such standards are counter-productive; responsible operators who would work towards reasonable standards are turned off and evade the standards. This situation arises because the selected standards tend to be copies of existing standards from industrialized countries where most of the work of developing standards has taken place. The standards they copy are the current high standards that are affordable in the West, but are not affordable in the DCs. A similar situation exists with respect to technology. Designs that work well in the West tend to be copied but do not function well in the DCs because the level of expertise needed to ensure proper performance does not exist, and cannot be recruited and retained at the low wage levels that most authorities are able to pay. The remedy in both cases is to ensure that standards are appropriate and that the constructed facilities will be appropriate and sustainable. They can be sustainable only if adequate funds are assured for a sound program of operation and maintenance. With the ever increasing competition for the use of scarce water resources, all control agencies have a duty to maximize the use of the water they are allocated. For urban water supply systems this means ensuring tight control of UFW. Privatization of UFW control may offer significant benefits for the DCs and merits serious consideration.  相似文献   
209.
Research on perception of parks and recreation settings has examined several important tree attributes that influence people's visual preferences. This research, however, has usually not considered the spatial arrangement of the trees, partly because of the lack of adequate methods for representing tree arrangements with systematically manipulated geometries. In the study reported here, computer video-imaging techniques were used to construct simulated landscape scenes that varied on specific dimensions of the spatial configuration of trees. The simulations were rated for visual preference by three respondent groups: a university class, a bicycle club, and a women's civic group. Preference ratings were significantly influenced by the number of trees in the scene, by the number of clumps into which trees were grouped, and by the diameter of the clumps. The video-imaging technology implemented in this study offers important methodological advantages for the design of carefully controlled experiments to study human response to variation in landscape treatments.  相似文献   
210.
Optimal foraging strategies and food choice are influenced by various factors, e.g. availability, size and caloric content of the food type and predation risk. However, food choice criteria may change when food is not eaten immediately but has to be carried to a storage site for later use. For example, handling time in terms of harvesting and transport time should be optimized, particularly when the risk of predation is high. Thus, it is not clear whether food selected by hoarding animals reflects their food preference due to intrinsic features of the food type, e.g. size, caloric or lipid content, or whether the food type selected is a compromise that also considers the handling time required for harvesting and transport. We investigate this question in relation to food hoarding behaviour in mound-building mice. In autumn, mound-building mice Mus spicilegus collect seeds and other plant material and cover it with soil. Such above-ground storage is quite unusual for rodents. Here, we investigated whether there is a relationship between the seed species preferred as building materials and those preferred for food. We conducted a seed preference test using three most collected weed species for mound building. Controlling factors like food availability or predation risk, mice prefer Setaria spp. as food, although Amaranthus spp. and Chenopodium spp. were preferentially harvested and stored. By including the availability of the three species, our experimental results were confirmed, namely, a clear preference for Setaria spp. Also, handling time and seed size revealed to influence plant choice.  相似文献   
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