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211.
212.
In Rocky Mountain National Park (RMNP), aspen (Populus tremuloides Michx.) has been observed to be declining on elk (Cervus elaphus nelsoni) winter range for many decades. To support elk management decisions, the SAVANNA ecosystem model was adapted to explore interactions between elk herbivory and aspen dynamics. The simulated probability of successful vegetative regeneration for senescent aspen stands declines sharply when elk densities reach levels of 3–5 elk/km2, depending on model assumptions for the seasonal duration of elk foraging activities. For aspen stands with a substantial component of younger trees, the simulated regeneration probability declines more continuously with increasing elk density, dropping below 50% from densities at 8–14 elk/km2.At the landscape scale, simulated aspen regeneration probability under a scenario of extensive seasonal use was little affected by elk population level, when this level was above 300–600 elk (25%–50% current population) over the ca. 107 km2 winter range. This was because elk distribution was highly aggregated, so that a high density of elk occupied certain areas, even at low population levels overall. At approximately current elk population levels (1000–1200 elk), only 35%–45% of senescent aspen stands are simulated as having at least a 90% probability of regeneration, nearly all of them located on the periphery of the winter range. Successful management for aspen persistence on core winter range will likely require some combination of elk population reduction, management of elk distribution, and fencing to protect aspen suckers from elk browsing. 相似文献
213.
The National Vegetation Classification Standard (NVCS) was implemented at two US National Park Service (NPS) sites in Texas,
the Padre Island National Seashore (PINS) and the Lake Meredith National Recreation Area (LMNRA), to provide information for
NPS oil and gas management plans. Because NVCS landcover classifications did not exist for these two areas prior to this study,
we created landcover classes, through intensive ground and aerial reconnaissance, that characterized the general landscape
features and at the same time complied with NVCS guidelines. The created landcover classes were useful for the resource management
and were conducive to classification with optical remote sensing systems, such as the Landsat Thematic Mapper (TM). In the
LMNRA, topographic elevation data were added to the TM data to reduce confusion between cliff, high plains, and forest classes.
Classification accuracies (kappa statistics) of 89.9% (0.89) and 88.2% (0.87) in PINS and LMNRA, respectively, verified that
the two NPS landholdings were adequately mapped with TM data. Improved sensor systems with higher spectral and spatial resolutions
will ultimately refine the broad classes defined in this classification; however, the landcover classifications created in
this study have already provided valuable information for the management of both NPS lands. Habitat information provided by
the classifications has aided in the placement of inventory and monitoring plots, has assisted oil and gas operators by providing
information on sensitive habitats, and has allowed park managers to better use resources when fighting wildland fires and
in protecting visitors and the infrastructure of NPS lands. 相似文献
214.
Lyman K. Thorsteinson Dale L. Taylor 《Journal of the American Water Resources Association》1997,33(4):795-810
ABSTRACT: The National Park Service and the National Biological Service initiated research in Denali National Park and Preserve, a 2.4 million-hectare park in southcentral Alaska, to develop ecological monitoring protocols for national parks in the Arctic/Subarctic biogeographic area. We are focusing pilot studies on design questions, on scaling issues and regionalization, ecosystem structure and function, indicator selection and evaluation, and monitoring technologies. Rock Creek, a headwater stream near Denali headquarters, is the ecological scale for initial testing of a watershed ecosystem approach. Our conceptual model embraces principles of the hydrological cycle, hypotheses of global climate change, and biological interactions of organisms occupying intermediate, but poorly studied, positions in Alaskan food webs. The field approach includes hydrological and depositional considerations and a suite of integrated measures linking key aquatic and terrestrial biota, environmental variables, or defined ecological processes, in order to establish ecological conditions and detect, track, and understand mechanisms of environmental change. Our sampling activities include corresponding measures of physical, chemical, and biological attributes in four Rock Creek habitats believed characteristic of the greater system diversity of Denali. This paper gives examples of data sets, program integration and scaling, and research needs. 相似文献
215.
Environmental auditing: Theory and applications 总被引:3,自引:0,他引:3
The environmental audit has become a regular part of corporate environmental management in Canada and is also gaining recognition
in the public sector. A 1991 survey of 75 private sector companies across Canada revealed that 76% (57/75) had established
environmental auditing programs. A similar survey of 19 federal, provincial, and municipal government departments revealed
that 11% (2/19) had established such programs. The information gained from environmental audits can be used to facilitate
and enhance environmental management from the single facility level to the national and international levels. This paper is
divided into two sections: section one examines environmental audits at the facility/company level and discusses environmental
audit characteristics, trends, and driving forces not commonly found in the available literature. Important conclusions are:
that wherever possible, an action plan to correct the identified problems should be an integral part of an audit, and therefore
there should be a close working relationship between auditors, managers, and employees, and that the first audits will generally
be more difficult, time consuming, and expensive than subsequent audits. Section two looks at environmental audits in the
broader context and discusses the relationship between environmental audits and three other environmental information gathering/analysis
tools: environmental impact assessments, state of the environment reports, and new systems of national accounts. The argument
is made that the information collected by environmental audits and environmental impact assessments at the facility/company
level can be used as the bases for regional and national state of the environment reports and new systems of national accounts. 相似文献
216.
浙江省灾害预防与经济协调发展的系统动态学模型 总被引:3,自引:0,他引:3
本文运用系统工程原理和系统动态学方法,构造了浙江省灾害预防与社会经济协调发展的系统动态学模型,并运用该模型对浙江省进行了初步的仿真研究,以寻求适宜的防灾政策。 相似文献
217.
ABSTRACT: The development of a nondegradation policy for high quality waters is a complex and often controversial process. This paper discusses the development of a nondegradation policy for two components of the National Wild and Scenic Rivers System. Water quality in these reaches of the Delaware River is threatened by rapid growth and development and the cumulative impacts from numerous wastewater discharges and nonpoint sources of pollution. The Delaware River Basin Commission, with assistance from its member states and the National Park Service, conducted a highly public, six-year planning process to develop a nondegradation policy that protected existing water quality without impinging upon local and state economic development objectives. The resulting non-degradation policy includes such features as numeric definitions of existing water quality and measurable change; stringent point source requirements; nonpoint source requirements including watershed planning requirements; and other water quality management policies. 相似文献
218.
Guidelines to drawing ecologically sound boundaries for national parks and nature reserves 总被引:1,自引:0,他引:1
John B. Theberge 《Environmental management》1989,13(6):695-702
Ecological approaches to drawing boundaries for parks and reserves are developed, described as 15 guidelines. The five abiotic guidelines are designed with the principle objective of maintaining drainage basin integrity. The ten biotic guidelines are designed to reduce as little as possible the natural diversity of populations in both the total natural area and in the communities directly traversed by the boundary line. Three of the biotic guidelines apply to maintaining community diversity, the remainder to species diversity. These guidelines are applied to a 2500-km2 potential national park in a montane environment in the southwest Yukon Territory. They were successful in generating the conclusion that boundaries in the subalpine best satisfy the guidelines in this environment. 相似文献
219.
Margot W. Garcia 《Environmental management》1989,13(5):583-592
The National Forest Management Act and National Environmental Policy Act require the use of an interdisciplinary team (ID team) to do integrated resource planning for the National Forests and the concurrent environmental analysis. A survey sent to all National Forest planning officers (82% response) reveals the composition of the ID teams used in integrated resource and land management planning. More than half the National Forests ID teams met NEPA and NFMA compositional requirements. National Forest planners recount their experiences with these ID teams. Despite frustrations with many aspects of the ID teams, the planners strongly support the idea that ID teams are an important part of the land-use planning process and think that their use leads to better National Forest integrated resource plans. 相似文献
220.
Ian Brotherton 《Journal of Environmental Planning and Management》1989,32(2):121-127
This paper appraises, in the context of the current debate concerning national parks for Scotland, factors that may have contributed to the achievement of national park purposes in England and Wales. Voluntary support, presumptions and resources are seen as crucial to the achievement of those purposes; while the few extra powers available to the national park authorities and the plan making process are seen to be of some importance. In contrast, it is argued that the much‐debated nature of the administrative authority has had little effect on the extent to which park purposes are achieved. 相似文献