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41.
We introduce a new index for measuring perpendicularity of animal movements with respect to a boundary (e.g., a habitat patch edge), and provide a computer algorithm for its calculation. Our index, η, improves on an approach that measures perpendicularity with respect to a fixed boundary direction. This is because η accounts for moment-to-moment trajectories relative to nearest-neighbor boundary attributes at the scale of an animal's movement. Our algorithm prp calculates η efficiently and accurately with both synthetic data and large telemetry datasets. In addition, we have included routines in prp which account for scenarios inherently problematic to perpendicularity estimators. 相似文献
42.
研究了用超声波萃取城市污水处理厂污泥中动植物油和矿物油的方法,并与索氏提取法进行比较.结果表明,超声波萃取法对污泥中矿物油和动植物油测定操作简单快速,标样回收率高,精密度好. 相似文献
43.
James G. Titus 《Environmental management》1991,15(1):39-58
Climatologists generally expect an anthropogenic global warming that could raise sea level 30–150 cm in the next century and
more thereafter. One of the impacts would be the loss of coastal wetlands. Although the inundation of adjacent dryland would
enable new wetlands to form, much of this land is or will soon be developed. If developed areas are protected, wetlands will
be squeezed between an advancing sea and the land being protected, which has already happened in China and the Netherlands,
where people have built dikes for centuries.
Unlike those countries, the United States has enough land to accommodate the landward migration of wetlands; but governments
lack the funds to purchase all the coastal lowlands that might be inundated and the legal authority to prohibit their development.
We propose a third approach: allowing property owners to use coastal lowlands today as they choose, but setting up a legal
mechanism to ensure that the land is abandoned if and when sea level rises enough to inundate it. Although compensation may
be required, this approach would cost less than 1% as much as purchasing the land, and would be (1) economically efficient
by enabling real estate markets to incorporate expectations of future sea level rise; (2) constitutional by compensating property
owners; and (3) politically feasible by pleasing people who care about the long-term fate of the coastal environment without
disturbing people who either are unconcerned about the distant future or do not believe sea level will rise.
This article demonstrates that it would be irrational to delay policy formulation until sea level rise projections are more
precise. The cost will be small if we act now but great if we wait, and sea level is already rising along most coasts. The
US government should develop a strategy in the next three years.
The opinions expressed in this paper do not necessarily reflect the views of EPA and no official endorsement should be inferred. 相似文献
44.
试论畜牧业污染和畜产品公害与绿色环保畜牧业 总被引:1,自引:0,他引:1
分析了畜牧业发展给环境带来的影响、环境污染给畜牧业的生产带来的影响以及被污染的畜产品给人类带来的危害;提出了建立绿色环保畜牧业的基本思路。 相似文献
45.
J. A. Laws B. F. Pain S. C. Jarvis D. Scholefield 《Agriculture, ecosystems & environment》2000,80(3):1032
Past research on nitrogen (N) inputs, losses and surpluses focused on separate components of grassland management, i.e., grazed or cut swards and the impact of fertiliser or slurry applications. In practice, however, grassland is both grazed and cut for conservation, and N fertiliser is supplied from both organic and inorganic sources. A whole systems approach was used to evaluate the effects of combinations of management strategies designed to reduce N losses on N budgets, and herbage and animal production in South West England. Three systems with contrasting N inputs were compared: CN, conventional mineral N application and broadcast slurry; TN, tactical mineral N application with slurry injection and the early housing of cattle; GC, a mixed grass/white clover sward with no mineral N addition and slurry injection. Comparisons were made on two contrasting soil types: a freely-draining sandy loam (Gleysol, Site 1), and a poorly drained clay (Luvisol, Site 2). 1 ha farmlets were grazed to a target sward height by beef cattle for a 5-year (Site 1) or a 4-year (Site 2) period. Herbage surplus to grazing requirements was cut for silage. On average, 185 kg N ha−1 was applied annually to treatment TN compared with 280 kg N ha−1 for CN. An additional 76, 102 and 67 kg N ha−1 was applied in slurry to treatments CN, TN and GC, respectively. Substantial reductions in N surpluses were achieved for both treatments TN and GC compared with treatment CN (N surpluses ha−1: 254, 168 and 119 kg at Site 1, and 247 kg, 190 and 73 kg at Site 2, for CN, TN and GC, respectively). The highest N input for treatment CN was associated with the greatest animal and herbage production. More land was required for grazing on treatment GC and less herbage was cut for silage so that self-sufficiency was not attained for winter fodder on this treatment. The early removal of cattle on treatment TN did not result in a significant increase in the amount of herbage cut for silage. It was concluded that the combinations of mitigation options used were successful in reducing N surpluses compared with the conventional N management system, but animal and herbage production was reduced. 相似文献
46.
Coleman SW 《Die Naturwissenschaften》2008,95(10):981-986
Distinct acoustic whistles are associated with the wing-beats of many doves, and are especially noticeable when doves ascend
from the ground when startled. I thus hypothesized that these sounds may be used by flock-mates as cues of potential danger.
To test this hypothesis, I compared the responses of mourning doves (Zenaida macroura), northern cardinals (Cardinalis cardinalis), and house sparrows (Passer domesticus) to audio playbacks of dove ‘startle wing-whistles’, cardinal alarm calls, dove ‘nonstartle wing-whistles’, and sparrow ‘social
chatter’. Following playbacks of startle wing-whistles and alarm calls, conspecifics and heterospecifics startled and increased
vigilance more than after playbacks of other sounds. Also, the latency to return to feeding was greater following playbacks
of startle wing-whistles and alarm calls than following playbacks of other sounds. These results suggest that both conspecifics
and heterospecifics may attend to dove wing-whistles in decisions related to antipredator behaviors. Whether the sounds of
dove wing-whistles are intentionally produced signals warrants further testing. 相似文献
47.
Integrated Use of GLEAMS and GIS to Prevent Groundwater Pollution Caused by Agricultural Disposal of Animal Waste 总被引:1,自引:0,他引:1
Monica Garnier Antonio Lo Porto Renzo Marini Antonio Leone 《Environmental management》1998,22(5):747-756
/ In modern intensive animal farming the disposal of a large amount of waste is of great concern, as, if not properly performed, it can cause the pollution of water, mainly because of the high content of nitrate and phosphate. This paper presents the results of a study intended to assess the environmental sustainability of animal waste disposal on agricultural soils in the alluvial plain of the River Chiana (Tuscany, Italy), a particularly sensitive area because of the high vulnerability of the shallow aquifer and of the intensive agricultural and breeding activities. With this aim, a strategy has been employed, that consists of the integrated use of a management model and GISs. The consequences on groundwater of applying animal waste to different kind of soils and crop arrangements have been simulated by means of the management model GLEAMS (Groundwater Loading Effects of Agricultural Management Systems, ver 2.01). As the huge amount of data required by such a sophisticated model does not allow applications at a scale larger than the field size, IDRISI and GRASS GIS packages have been used to divide the study area into land units, with homogeneous environmental characteristics, and then to generalize on these units the outputs of the model. The main conclusions can be synthesized as follows: The amount of animal waste produced in some of the investigated areas (i.e., municipal territory) is greater than that disposable on their own agricultural soil with no risks to the groundwater; consequently a cooperative approach among municipalities is necessary in order to plan waste disposal in a comprehensive and centralized way.KEY WORDS: Land use; Animal waste disposal; Groundwater protection; GIS, Management models 相似文献
48.
G. Wittemyer W. M. Getz F. Vollrath I. Douglas-Hamilton 《Behavioral ecology and sociobiology》2007,61(12):1919-1931
The structure of dominance relationships among individuals in a population is known to influence their fitness, access to
resources, risk of predation, and even energy budgets. Recent advances in global positioning system radio telemetry provide
data to evaluate the influence of social relationships on population spatial structure and ranging tactics. Using current
models of socio-ecology as a framework, we explore the spatial behaviors relating to the maintenance of transitive (i.e.,
linear) dominance hierarchies between elephant social groups despite the infrequent occurrence of contests over resources
and lack of territorial behavior. Data collected from seven families of different rank demonstrate that dominant groups disproportionately
use preferred habitats, limit their exposure to predation/conflict with humans by avoiding unprotected areas, and expend less
energy than subordinate groups during the dry season. Hence, our data provide strong evidence of rank derived spatial partitioning
in this migratory species. These behaviors, however, were not found during the wet season, indicating that spatial segregation
of elephants is related to resource availability. Our results indicate the importance of protecting preexisting social mechanisms
for mitigating the ecological impacts of high density in this species. This analysis provides an exemplar of how behavioral
research in a socio-ecological framework can serve to identify factors salient to the persistence and management of at risk
species or populations.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
49.
Many animal signals are performed in a highly redundant manner as in some bird species where males sing several renditions of one song type before switching to another. However, differences in signal redundancy between contexts and between individuals are only poorly understood. We found that chaffinches (Fringilla coelebs) in noisier areas (i.e., close to waterfalls and torrents) sang longer bouts of the same song type before switching to a new type, suggesting that they use increased serial redundancy to get the message across in noisy conditions. This is the first evidence of a noise-dependent adjustment of signal redundancy in a songbird. In addition, we found that song types with faster trills were sung in shorter bouts suggesting that the performance of highly redundant song series is probably limited by motor constraints. Thus, in noisy environments, serial redundancy in bird song may reflect a trade-off between successful signal transmission and preventing motor fatigue. 相似文献
50.
JAIME L. PETERS ALEX J. SUTTON DAVID R. JONES LESLEY RUSHTON KEITH R. ABRAMS 《Journal of environmental science and health. Part. B》2013,48(7):1245-1258
To maximize the findings of animal experiments to inform likely health effects in humans, a thorough review and evaluation of the animal evidence is required. Systematic reviews and, where appropriate, meta-analyses have great potential in facilitating such an evaluation, making efficient use of the animal evidence while minimizing possible sources of bias. The extent to which systematic review and meta-analysis methods have been applied to evaluate animal experiments to inform human health is unknown. Using systematic review methods, we examine the extent and quality of systematic reviews and meta-analyses of in vivo animal experiments carried out to inform human health. We identified 103 articles meeting the inclusion criteria: 57 reported a systematic review, 29 a systematic review and a meta-analysis, and 17 reported a meta-analysis only. The use of these methods to evaluate animal evidence has increased over time. Although the reporting of systematic reviews is of adequate quality, the reporting of meta-analyses is poor. The inadequate reporting of meta-analyses observed here leads to questions on whether the most appropriate methods were used to maximize the use of the animal evidence to inform policy or decision-making. We recommend that guidelines proposed here be used to help improve the reporting of systematic reviews and meta-analyses of animal experiments. Further consideration of the use and methodological quality and reporting of such studies is needed. 相似文献