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11.
Using nocturnal cold air drainage flow to monitor ecosystem processes in complex terrain. 总被引:1,自引:0,他引:1
Thomas G Pypker Michael H Unsworth Alan C Mix William Rugh Troy Ocheltree Karrin Alstad Barbara J Bond 《Ecological applications》2007,17(3):702-714
This paper presents initial investigations of a new approach to monitor ecosystem processes in complex terrain on large scales. Metabolic processes in mountainous ecosystems are poorly represented in current ecosystem monitoring campaigns because the methods used for monitoring metabolism at the ecosystem scale (e.g., eddy covariance) require flat study sites. Our goal was to investigate the potential for using nocturnal down-valley winds (cold air drainage) for monitoring ecosystem processes in mountainous terrain from two perspectives: measurements of the isotopic composition of ecosystem-respired CO2 (delta13C(ER)) and estimates of fluxes of CO2 transported in the drainage flow. To test if this approach is plausible, we monitored the wind patterns, CO2 concentrations, and the carbon isotopic composition of the air as it exited the base of a young (approximately 40 yr-old) and an old (>450 yr-old) steeply sided Douglas-fir watershed. Nocturnal cold air drainage within these watersheds was strong, deep, and occurred on more than 80% of summer nights. The depth of cold air drainage rapidly increased to tower height or greater when the net radiation at the top of the tower approached zero. The carbon isotope composition of CO2 in the drainage system holds promise as an indicator of variation in basin-scale physiological processes. Although there was little vertical variation in CO2 concentration at any point in time, we found that the range of CO2 concentration over a single evening was sufficient to estimate delta 13C(ER) from Keeling plot analyses. The seasonal variation in delta 13C(ER) followed expected trends: during the summer dry season delta 13C(ER) became less negative (more enriched in 13C), but once rain returned in the fall, delta 13C(ER) decreased. However, we found no correlation between recent weather (e.g., vapor pressure deficit) and delta 13C(ER) either concurrently or with up to a one-week lag. Preliminary estimates suggest that the nocturnal CO2 flux advecting past the 28-m tower is a rather small fraction (<20%) of the watershed-scale respiration. This study demonstrates that monitoring the isotopic composition and CO2 concentration of cold air drainage at the base of a watershed provides a new tool for quantifying ecosystem metabolism in mountainous ecosystems on the basin scale. 相似文献
12.
13.
Conservation Biology and Carnivore Conservation in the Rocky Mountains 总被引:17,自引:0,他引:17
14.
Richard Engeman Troy Hershberger Steve Orzell Rodney Felix Gary Killian John Woolard Jon Cornman David Romano Chet Huddleston Pat Zimmerman Chris Barre Eric Tillman Michael Avery 《Environmental science and pollution research international》2014,21(12):7689-7697
Feral swine were targeted for control at Avon Park Air Force Range in south-central Florida to avert damage to sensitive wetland habitats on the 40,000-ha base. We conducted a 5-year study to assess impacts from control to this population that had been recreationally hunted for many years. Control was initiated in early 2009. The feral swine population was monitored from 2008 to 2012 using a passive tracking index (PTI) during the dry and wet seasons and using recreational hunter take rates from the dry season. All three indices showed substantial feral swine declines after implementing control, with indices leveling for the final two study years. Military missions and recreational hunting seasons impacted temporal and spatial consistency of control application, thereby limiting further impacts of control efforts on the feral swine population. The PTI was also able to monitor coyotes, another invasive species on the base, and detect Florida black bear and Florida panther, species of particular concern. 相似文献
15.
Legally designated wilderness areas are acknowledged to be an important element in strategies to conserve biological diversity
in United States. However, because of the restrictions on consumptive uses in wilderness, their establishment is normally
contentious. Criteria for establishment have typically been associated with opportunity and aesthetic and experiential values.
Biological data have not normally played a major role in guiding wilderness establishment. We present four wilderness allocation
options for those public lands considered suitable for wilderness designation in Idaho. These options cover the span of choices
presently available to wilderness planners in the state and range from not establishing any new wilderness areas to the inclusion
of all suitable lands in wilderness. All options are evaluated using spatial biological data from the National Biological
Survey's Gap Analysis Project. A conservation strategy that would protect a minimum of 10% of the area occupied by each of
113 native vegetation types and at a minimum 10% of the distribution of each of 368 vertebrate species was evaluated for each
option. Only the inclusion of all suitable lands in wilderness, creating a system of 5.1 million ha came close to achieving
these goals, protecting 65% of the vegetation types and 56% of the vertebrate species. We feel this approach, which allows
planners to evaluate the ecological merits of proposed widerness units along with other values, can provide a means to resolve
the impasse over additional wilderness designation in Idaho. 相似文献
16.
Mahbub Alam Todd P. Trooien Troy J. Dumler Danny H. Rogers 《Journal of the American Water Resources Association》2002,38(6):1715-1721
ABSTRACT: A test of the suitability of subsurface drip irrigation (SDI) for alfalfa (Medicago sativa L) compared to a sprinkler, was conducted on a Kansas producer's field where the soil is loam. The treatments included drip tape spacing of 60, 40, and 30 inches placed at depths of 18 and 12 inches. A nearby plot irrigated by a center pivot sprinkler was seeded to alfalfa and used for comparison. Seedling emergence and yield were adversely affected at 60 inch spacing, while the depth of placement of drip tapes (18 and 12 inches) showed no effect on yield. The site served for education and allowed comparison between SDI tape spacing and center pivot system. 相似文献
17.
Establishing the relationship between level of safety climate and safety performance is a current challenge. This work examines the relationship between level of safety climate and orientation toward safety in the decision making process and choice. Alternatively, this work seeks to answer the question of whether level of safety climate can predict safety-oriented decision making. A generalized safety climate questionnaire and a decision making simulation are utilized to examine this relationship. The results indicate that level of safety climate is not a significant predictor of the decision process; however, it was found to be a significant predictor of the selection of safer choices. 相似文献
18.
In this article, we examine how issues of scale affect the integration of recreation management with the management of other
natural resources on public lands. We present two theories used to address scale issues in ecology and explore how they can
improve the two most widely applied recreation-planning frameworks. The theory of patch dynamics and hierarchy theory are
applied to the recreation opportunity spectrum (ROS) and the limits of acceptable change (LAC) recreation-planning frameworks.
These frameworks have been widely adopted internationally, and improving their ability to integrate with other aspects of
natural resource management has significant social and conservation implications. We propose that incorporating ecologic criteria
and scale concepts into these recreation-planning frameworks will improve the foundation for integrated land management by
resolving issues of incongruent boundaries, mismatched scales, and multiple-scale analysis. Specifically, we argue that whereas
the spatially explicit process of the ROS facilitates integrated decision making, its lack of ecologic criteria, broad extent,
and large patch size decrease its usefulness for integration at finer scales. The LAC provides explicit considerations for
weighing competing values, but measurement of recreation disturbances within an LAC analysis is often done at too fine a grain
and at too narrow an extent for integration with other recreation and resource concerns. We suggest that planners should perform
analysis at multiple scales when making management decisions that involve trade-offs among competing values. The United States
Forest Service is used as an example to discuss how resource-management agencies can improve this integration. 相似文献
19.
This article investigates how remotely sensed lawn characteristics, such as parcel lawn area and parcel lawn greenness, combined
with household characteristics, can be used to predict household lawn fertilization practices on private residential lands.
This study involves two watersheds, Glyndon and Baisman’s Run, in Baltimore County, Maryland, USA. Parcel lawn area and lawn
greenness were derived from high-resolution aerial imagery using an object-oriented classification approach. Four indicators
of household characteristics, including lot size, square footage of the house, housing value, and housing age were obtained
from a property database. Residential lawn care survey data combined with remotely sensed parcel lawn area and greenness data
were used to estimate two measures of household lawn fertilization practices, household annual fertilizer nitrogen application
amount (N_yr) and household annual fertilizer nitrogen application rate (N_ha_yr). Using multiple regression with multi-model inferential procedures, we found that a combination of parcel lawn area and
parcel lawn greenness best predicts N_yr, whereas a combination of parcel lawn greenness and lot size best predicts variation in N_ha_yr. Our analyses show that household fertilization practices can be effectively predicted by remotely sensed lawn indices and
household characteristics. This has significant implications for urban watershed managers and modelers. 相似文献
20.
Abel TD 《Environmental management》2008,42(2):232-248
This article presents a case study of Toxics Release Inventory (TRI) air pollution exposure risks across metropolitan St. Louis. The first section critically reviews environmental justice research and related barriers to environmental risk management. Second, the paper offers a conventional analysis of the spatial patterns of TRI facilities and their surrounding census block group demographics for metropolitan St. Louis. Third, the article describes the use of an exposure risk characterization for 319 manufacturers and their air releases of more than 126 toxic pollutants. This information could lead to more practical resolutions of urban environmental injustices. The analysis of TRIs across metropolitan St. Louis shows that minority and low-income residents were disproportionately closer to industrial pollution sources at nonrandom significance levels. Spatial concentrations of minority residents averaged nearly 40% within one kilometer of St. Louis TRI sites compared to 25% elsewhere. However, one-fifth of the region's air pollution exposure risk over a decade was spatially concentrated among only six facilities on the southwestern border of East St. Louis. This disproportionate concentration of some of the greatest pollution risk would never be considered in most conventional environmental justice analyses. Not all pollution exposure risk is average, and the worst risks deserve more attention from environmental managers assessing and mitigating environmental injustices. 相似文献