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排序方式: 共有118条查询结果,搜索用时 31 毫秒
1.
New birds on the block: new neighbors increase defensive costs for territorial male willow ptarmigan 总被引:4,自引:0,他引:4
Previous researchers have hypothesized that site-faithful animals may benefit from the presence of familiar neighbors. This study compares the relative costs of territorial defense against new and former neighbors by male willow ptarmigan (Lagopus lagopus). Territorial defense against new neighbors appeared to require a greater expenditure of both time and effort than did defense against former neighbors. Territorial males that had several new neighbors spent a higher proportion of time fighting than did males with fewer new neighbors, and males with both new and former neighbors spent a greater amount of time fighting with their new neighbors, on average, than with their former neighbors. In addition, fights with new neighbors occurred relatively more frequently and were longer than fights with former neighbors. Finally, fights involving new neighbors tended to escalate to higher levels than fights between former neighbors. Reduced defensive costs for site-faithful, territorial males may provide one explanation for the tendency of males to be more site-faithful than females in many species. 相似文献
2.
Phillip N. Price Curtis M. Oldenburg 《International Journal of Greenhouse Gas Control》2009,3(5):658-663
Geologic carbon sequestration is the injection of anthropogenic CO2 into deep geologic formations where the CO2 is intended to remain indefinitely. If successfully implemented, geologic carbon sequestration will have little or no impact on terrestrial ecosystems aside from the mitigation of climate change. However, failure of a geologic carbon sequestration site, such as large-scale leakage of CO2 into a potable groundwater aquifer, could cause impacts that would require costly remediation measures. Governments are attempting to develop regulations for permitting geologic carbon sequestration sites to ensure their safety and effectiveness. At present, these regulations focus largely on decreasing the probability of failure. In this paper we propose that regulations for the siting of early geologic carbon sequestration projects should emphasize limiting the consequences of failure because consequences are easier to quantify than failure probability. 相似文献
3.
在杭州市现有区域环境噪声手工监测点位的基础上,结合地理分布,采用系统聚类法对2012年149个点位的数据样本分类、合并,将149个点位优化到26个,并用T检验法验证数据可靠性。优化前后各城区的点位分布比例相差不大,等效声级绝对误差在1.0 d B(A)内,相对误差不超过±5%。经过2013年和2014年数据验证,确定优化后的点位能体现声环境功能区的代表性。 相似文献
4.
A method to estimate the impact of clear-cutting on nutrient concentrations in boreal headwater streams 总被引:1,自引:0,他引:1
Large-scale forestry operations, like clear-cutting, may impair surface water quality if not done with environmental considerations in mind. Catchment and country level estimates of nutrient loads from forestry are generally based on specific export values, i.e., changes in annual exports due to the implemented forestry operations expressed in kg ha−1. We introduce here a specific concentration approach as a method to estimate the impact of clear-cutting on nutrient concentrations and export in headwater streams. This new method is potentially a more dynamic and flexible tool to estimate nutrient loads caused by forestry, because variation in annual runoff can be taken into account in load assessments. We combined water quality data from eight boreal headwater catchment pairs located in Finland and Sweden, where the effect of clear-cutting on stream water quality has been studied experimentally. Statistically significant specific concentration values could be produced for total nitrogen, nitrate, ammonium, and phosphate. The significant increases in the concentrations of these nutrients occurred between 2 and 6 years after clear-cutting. Significant specific concentration values could not be produced for total phosphorus and total organic carbon with the whole dataset, although in some single studies significant increases in their concentrations after clear-cutting were observed. The presented method enables taking into account variation in runoff, temporal dynamics of effects, and the proportional size of the treated area in load calculations. The number of existing studies considering large site-specific variation in responses to clear-cutting is small, and therefore further empirical studies are needed to improve predictive capabilities of the specific concentration values. 相似文献
5.
Moritz Albrecht 《Journal of Environmental Planning and Management》2010,53(6):725-742
This study describes the governance and management structures of the Curonian Spit World Heritage Site, a transboundary protected area shared by Lithuania and the Russian Federation. Focusing on the national park authorities it presents the site from a local administrative perspective. The paper shows that due to strong state level influence and a lack of full stakeholder inclusion, different philosophies and priorities on both sides of the border challenge common management efforts and co-operation. Presenting the existing problems the paper points out the need for increased efforts at the state level as well as for the full inclusion of local communities to remove obstacles and foster co-operation. Hence, by adapting to certain environmental and transboundary governance principles, conflicts can be avoided and better results achieved. 相似文献
6.
The land evaluation and site assessment (LESA) method has been used extensively in the United States to assess agricultural
land suitability for different localities. Despite widespread use, LESA models rarely have been evaluated in a systematic,
comprehensive manner. This article discusses development of a LESA system for Hawaii, the first statewide application of the
LESA methodology. The empirical model was implemented with a computerized geographic information system (GIS). The system's
efficiency, ability to discriminate among land parcels, and robustness to subjective model parameter values are evaluated
with statistical analyses and map overlays of GIS data. Results show great potential to simplify the original model specification,
primarily through deletion of marginal site assessment factors. System output was generally insensitive to the numeric values
selected for model parameters, with exception of the ratio used to combine the land evaluation (LE) and site assessment (SA)
component scores. Relative supplies of the differing land attributes measured by the two components must be considered in
determining an appropriate LE:SA ratio for a given area. 相似文献
7.
A method is described for the rapid survey and determination of the ecological value of woodlots. The three dominant tree species in a stand are given a visual ranking that is converted to awoodlot index through the use of species adaptation values. The woodlot index is scaled by presettlement vegetation type to yield awoodlot scale. The ecologically most valuable woodlots in a region are identified by using the woodlot scale and data on woodlot area, human disturbance, and tree density. The woodlot index corresponds closely to results from conventional methods of woodlot surveys. This method should be valuable to land-use planners for environmental impact assessment and regional planning. 相似文献
8.
Agricultural land evaluation and site assessment in the United States: An introduction 总被引:2,自引:0,他引:2
Frederick Steiner 《Environmental management》1987,11(3):375-377
The US Soil Conservation Service has developed an agricultural land evaluation and site assessment (LESA) system. The LESA system is being used by the US Department of Agriculture and other federal agencies to implement the Farmland Protection Policy Act of 1981. The LESA system and three case studies from the Pacific North-west are introduced in this article.Scientific Paper no. 7166, College of Agriculture and Home Economics Research Paper. Washington State University, Pullman, Washington. Project no. 0010. 相似文献
9.
Inhaber H 《Environmental management》2001,28(4):505-517
The Nevada Test Site (NTS), north of Las Vegas, was the scene of hundreds of nuclear weapons tests over four decades, both
above- and belowground. There is considerable interest, both in neighboring communities and elsewhere, in the risks it poses.
Overall, the greatest risks are nonradioactive in origin, with occupational risks to employees and accident risks in transporting
low-level nuclear wastes to the NTS from other Department of Energy (DOE) sites ranking highest. For radiation risks, that
to workers handling radioactive materials is much higher than that to the surrounding population, either present or future.
Overall, annual risks are small, with all fatalities approximately 0.008% of total Nevada deaths. At the NTS, the government
spends about 5000 times more on radiation as opposed to nonradiation deaths. This suggests that at least some resources may
be misallocated towards cleanup of public risks and that the occupational risk of cleanup may be much higher than the public
risk. Thus risk may be multiplied by well-meaning programs. 相似文献
10.
/ Environmental regulatory agencies are responsible for protecting human health and the environment in their constituencies. Their responsibilities include the identification, evaluation, and cleanup of contaminated sites. Leaking underground storage tanks (USTs) constitute a major source of subsurface and groundwater contamination. A significant portion of a regulatory body's efforts may be directed toward the management of UST-contaminated sites. In order to manage remedial sites effectively, vast quantities of information must be maintained, including analytical dataon chemical contaminants, remedial design features, and performance details. Currently, most regulatory agencies maintain such information manually. This makes it difficult to manage the data effectively. Some agencies have introduced automated record-keeping systems. However, the ad hoc approach in these endeavors makes it difficult to efficiently analyze, disseminate, and utilize the data. This paper identifies the information requirements for UST-contaminated site management at the Waste Cleanup Section of the Department of Environmental Resources Management in Dade County, Florida. It presents a viable design for an information management system to meet these requirements. The proposed solution is based on a back-end relational database management system with relevant tools for sophisticated data analysis and data mining. The database is designed with all tables in the third normal form to ensure data integrity, flexible access, and efficient query processing. In addition to all standard reports required by the agency, the system provides answers to ad hoc queries that are typically difficult to answer under the existing system. The database also serves as a repository of information for a decision support system to aid engineering design and risk analysis. The system may be integrated with a geographic information system for effective presentation and dissemination of spatial data. 相似文献