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91.
Abstract: The Northwest Forest Plan was implemented in 1994 to protect habitat for species associated with old‐growth forests, including Northern Spotted Owls (Strix occidentailis caurina) in Washington, Oregon, and northern California (U.S.A.). Nevertheless, 10‐year monitoring data indicate mixed success in meeting the ecological goals of the plan. We used the ecosystem management decision‐support model to evaluate terrestrial and aquatic habitats across the landscape on the basis of ecological objectives of the Northwest Forest Plan, which included maintenance of late‐successional and old‐growth forest, recovery, and maintenance of Pacific salmon (Oncorhynchus spp.), and viability of Northern Spotted Owls. Areas of the landscape that contained habitat characteristics that supported these objectives were considered of high conservation value. We used the model to evaluate ecological condition of each of the 36, 180 township and range sections of the study area. Eighteen percent of the study area was identified as habitat of high conservation value. These areas were mostly on public lands. Many of the sections that contained habitat of exceptional conservation value were on Bureau of Land Management land that has been considered for management‐plan revisions to increase timber harvests. The results of our model can be used to guide future land management in the Northwest Forest Plan area, and illustrate how decision‐support models can help land managers develop strategies to better meet their goals. 相似文献
92.
Gladden JN 《Environmental management》2001,27(3):367-376
The United States and Finland have passed laws to classify and manage Arctic wilderness areas, but their national policies
are based on different nature ideologies. Finns tend to perceive wilderness as a human-centered idea, while Americans are
inclined to see the same land from a nature-based point of view. Rural residents in the Arctic, and especially indigenous
peoples, use motorized vehicles for hunting and gathering in wilderness areas. Attempts of southern-based environmental groups
to restrict motor use by imposing a nature-based ideology on rural residents in northern Alaska will result in high levels
of political conflict. Alaska land managers need to respect the minority rights of rural residents and a study of wilderness
policies in Finnish Lapland is instructive toward this end. 相似文献
93.
Consequences and Costs of Conservation Corridors 总被引:19,自引:0,他引:19
94.
Extinction in Subdivided Habitats 总被引:4,自引:0,他引:4
95.
The high degree of physical disturbance associated with conventional response options to oil spills in wetlands is driving
the investigation of alternative cleanup methodologies. In March 1995, a spill of gas condensate in a brackish marsh at Rockefeller
Wildlife Refuge in southwestern Louisiana was remediated through the use of in situ burning. An assessment of vegetation recovery
was initiated in three treatment marshes: (1) oil-impacted and burned, (2) oil impacted and unburned, and (3) a nonoiled unburned
reference. We compared percent cover, stem density, and biomass in the treatment marshes to define ecological recovery of
the marsh vegetation and soil hydrocarbon content to determine the efficacy of in situ burning as a cleanup technique. Burning
led to a rapid decrease in soil hydrocarbon concentrations in the impacted-and-burned marsh to background levels by the end
of the first growing season. Although a management fire accidentally burned the oil-impacted-and-unburned and reference marshes
in December 1995, stem density, live biomass, and total percent cover values in the oil-impacted-and-burned marsh were equivalent
to those in the other treatment marshes after three years. In addition, plant community composition within the oil-impacted-and-burned
marsh was similar to the codominant mix of the grasses Distichlis spicata (salt grass) and Spartina patens (wire grass) characteristic of the surrounding marsh after the same time period. Rapid recovery of the oil-impacted-and-unburned
marsh was likely due to lower initial hydrocarbon exposure. Water levels inundating the soil surface of this grass-dominated
marsh and the timing of the in situ burn early in the growing season were important factors contributing to the rapid recovery
of this wetland. The results of this in situ burn evaluation support the conclusion that burning, under the proper conditions,
can be relied upon as an effective cleanup response to hydrocarbon spills in herbaceous wetlands. 相似文献
96.
Burger J Leschine TM Greenberg M Karr JR Gochfeld M Powers CW 《Environmental management》2003,31(2):0157-0167
More than 50 years of research, development, manufacture, and testing of nuclear weapons at Department of Energy (DOE) sites
has left a legacy of on-site contamination that often spreads to surrounding areas. Despite substantial cleanup budgets in
the last decade, the DOE's top-to-bottom review team concluded that relatively little actual cleanup has been accomplished,
although milestones have been met and work packages completed. Rather than solely use regulatory constraints to direct cleanup,
many people have suggested that human and ecological health should guide long-term stewardship goals of DOE-managed sites.
The main questions are how ecological and human health considerations should be applied in deciding the extent of cleanup
that contaminated sites should receive and how near-term and longer run considerations of costs and benefits should be balanced
as cleanup decisions are made. One effort to protect ecological integrity is the designation of the largest sites as National
Environmental Research Parks (NERPs). Recently, the Competitive Enterprise Institute (CEI) suggested isolating and conserving
DOE sites as a policy priority because of their rich ecological diversity. A more effective long-term stewardship approach
for former nuclear weapons complex sites may emerge if the guiding principles are to (1) reduce risks to human and ecological
health, (2) protect cultural traditions, and (3) lower short- and long-term cleanup and remediation costs. A “net benefits”
perspective that takes both near- and longer-term costs and consequences into account can help illuminate the trade-offs between
expensive cleanup in the near term and the need to assure long-term protection of human health, cultural values, and high
levels of biodiversity and ecological integrity that currently exist at many DOE sites. 相似文献
97.
Faunal Changes and Bottomland Hardwood Forest Loss in the Tensas Watershed, Louisiana 总被引:1,自引:0,他引:1
DAVID M. BURDICK DOUGLAS CUSHMAN † ROBERT HAMILTON JAMES G. GOSSELINK 《Conservation biology》1989,3(3):282-292
Intentamos asociar las diferencias entre las poblaclones de fauna en la cuenca de Tensas con las diferencias de extensión de áreas de bosques caducifolios de tierras bajas, usando datos existentes. La cuenca de Tensas era parte del area de distribución original de varias especies que actualmente están ausentes: lobo rojo, la puma de Florida, Pájaro Carpintero. El oso negro de Louisiana y Gorjeador de Bachman. también está en peligro de extinción. Los catastras de aves proporcionaron los mejores datos faunisticos Las comparaciones de poblaciones de aves (1) con la disminución del bosque caducifolio de tierras bajas al pasar del tiempo y (2) con áreas con diferentes superficies de este tipo de bosque apoyan la bipótesis de que el número de especies selvicolas y las densidades de población de especies del interior del bosque decrecieron junto con la disminución acumulativa en el área de bosques. Hemos señalado el deterioro de las poblaciones de fauna autoctona utilizando encuestas existentes de aves y datos cualitativos, demostrando la utilidad del enfoque del impacto acumulativo a una escala de cuencas hidrográfica Asegurando la conservación de los habitats necesarioq un plan de munejo de impacto acumulativo reducería extinciones adicionales en esta cuenca hidrográfica. 相似文献
98.
Conservation Status as a Biodiversity Trend Indicator: Recommendations from a Decade of Listing Species at Risk in British Columbia 总被引:3,自引:0,他引:3
Abstract: Species conservation status is commonly used as a broad-scale indicator of the state of biological diversity. To learn about its value for tracking trends, we examined provincial lists of terrestrial vertebrate species and subspecies at risk in British Columbia, Canada, for 1992 and 2002 to see whether changes in these lists reflected changes in the status of the taxa they represent. Examination of the case histories of individual species and subspecies showed that 65% of additions and deletions to the British Columbia Red List were the result of improvement in knowledge of species status, changes in assessment procedures, and refinements in taxonomy rather than actual changes in a species' status. Comparison to an alternate set of rank scores provided by NatureServe for taxa that appeared on both 1992 and 2002 British Columbia Red Lists revealed changes in status that were not reflected by movement from the list. Estimates of historical conservation status for species on the 1992 British Columbia Red List demonstrated ambiguity around the natural baseline with regard to tracking changes in list composition over time. We discourage the continued use of indicators based solely on conservation status as a means of tracking biodiversity. Instead we recommend advancing strategic indicators around species at risk based on long-term monitoring data, deliberate and explicitly stated baselines, and consistent methods of conservation ranking. 相似文献
99.
WILLIAM E. JAMES 《Natural resources forum》1985,9(3):197-204
Energy demand, including demand for petroleum, is expected to increase at a faster rate in the rapidly-developing nations of East and Southeast Asia than elsewhere in the world through the turn of the century. In the aggregate, the countries of this region are heavily dependent on imported oil, coal and natural gas. Rapid industrialization, electrification and increased consumer demand for energy-consuming durable goods and housing underlie the expected strong growth in energy consumption. Substantial scope for greater economy in energy-use exists in the industrial and transport sectors but effects in these areas will require effective management and institutional support in addition to getting prices right. In the context of balance of payments and external debt considerations, and the continued growth of energy consumption in East and Southeast Asia, improving energy conservation will be of great importance in lessening the likelihood that future economic development will be constrained by energy problems. 相似文献
100.
Measuring the biodegradability of nonylphenol ether carboxylates, octylphenol ether carboxylates, and nonylphenol 总被引:12,自引:0,他引:12
We examined the biodegradability of several metabolites of C8- and C9-alkylphenol ethoxylates, including nonylphenoxyacetic acid (NPEC1), nonylphenoxyethoxyacetic acid (NPEC2), octylphenoxyacetic acid (OPEC1), octylphenoxyethoxyacetic acid (OPEC2), and nonylphenol (NP). Using OECD method 301B (modified Sturm method), OPEC1 and OPEC2 are readily biodegradable: both compounds exceeded 60% of theoretical CO2 formation (ThCO2) by day 28, and required less than 10 days to go from 10% to 60% ThCO2. Also using method 301B, NPEC1 and NPEC2 exceeded 60% ThCO2 at day 28, but did not meet the 10 day window. Using OECD method 301F, the manometric respirometry method that measures oxygen consumption, approximately 62% of NP was biodegraded in 28 days, but required more than 10 days to go from 10% to 60% biodegradation. While the validity of the "10-day window" is currently being debated within OECD, the data show that the common metabolites of C8- and C9-APEs are rapidly degraded in the test systems used, which strongly suggests that they would not accumulate or persist in the environment. 相似文献