排序方式: 共有29条查询结果,搜索用时 15 毫秒
21.
Remotely sensed data have been used extensively for environmental monitoring and modeling at a number of spatial scales; however,
a limited range of satellite imaging systems often constrained the scales of these analyses. A wider variety of data sets
is now available, allowing image data to be selected to match the scale of environmental structure(s) or process(es) being
examined. A framework is presented for use by environmental scientists and managers, enabling their spatial data collection
needs to be linked to a suitable form of remotely sensed data. A six-step approach is used, combining image spatial analysis
and scaling tools, within the context of hierarchy theory. The main steps involved are: (1) identification of information
requirements for the monitoring or management problem; (2) development of ideal image dimensions (scene model), (3) exploratory
analysis of existing remotely sensed data using scaling techniques, (4) selection and evaluation of suitable remotely sensed
data based on the scene model, (5) selection of suitable spatial analytic techniques to meet information requirements, and
(6) cost–benefit analysis. Results from a case study show that the framework provided an objective mechanism to identify relevant
aspects of the monitoring problem and environmental characteristics for selecting remotely sensed data and analysis techniques. 相似文献
22.
Military Participation in Emergency Humanitarian Assistance 总被引:1,自引:0,他引:1
Military forces of the United States and other countries possess training, equipment and capabilities that are suited for work in disaster preparedness and assistance. Information on the use of military units in domestic and foreign disaster-related efforts, particularly by United States forces in the medical area, was obtained by review of the literature and unpublished military reports, and from interviews with people who have been involved with disaster-related activities. The historical reasons for viewing United States forces as resources in disaster situations are identified. Additionally, issues and problems related to disaster preparedness and assistance in general, and more specifically, to the past and future use of military personnel for this mission are examined. The need for a defined military mission for emergency humanitarian assistance and the need for a military organizational structure to support this mission are identified. Once these two critical issues have been properly addressed, the United States military should participate in the establishment of a disaster institute for joint civilian-military disaster planning and training, in both domestic and foreign areas. 相似文献
23.
As drivers of terrestrial ecosystems, humans have replaced large carnivores in most areas, and human influence not only exerts striking ecological pressures on biodiversity at local scales but also has indirect effects in distant corners of the world. We suggest that the multibillion dollar cashmere industry creates economic motivations that link western fashion preferences for cashmere to land use in Central Asia. This penchant for stylish clothing, in turn, encourages herders to increase livestock production which affects persistence of over 6 endangered large mammals in these remote, arid ecosystems. We hypothesized that global trade in cashmere has strong negative effects on native large mammals of deserts and grassland where cashmere‐producing goats are raised. We used time series data, ecological snapshots of the biomass of native and domestic ungulates, and ecologically and behaviorally based fieldwork to test our hypothesis. In Mongolia increases in domestic goat production were associated with a 3‐fold increase in local profits for herders coexisting with endangered saiga (Saiga tatarica).That increasing domestic grazing pressure carries fitness consequences was inferred on the basis of an approximately 4‐fold difference in juvenile recruitment among blue sheep (Pseudois nayaur)in trans‐Himalayan India. Across 7 study areas in Mongolia, India, and China's Tibetan Plateau, native ungulate biomass is now <5% that of domestic species. Such trends suggest ecosystem degradation and decreased capacity for the persistence of native species, including at least 8 Asian endemic species: saiga, chiru (Pantholops hodgsoni), Bactrian camel (Camelus bactrianus), snow leopard(Panthera uncia), khulan(Equus hemionus), kiang (E. kiang), takhi (E. przewalski), and wild yak (Bos mutus). Our results suggest striking yet indirect and unintended actions that link trophic‐level effects to markets induced by the trade for cashmere. Globalización del Mercado de Cachemira y la Declinación de Mamíferos Mayores en Asia Central 相似文献
24.
The Ecological Future of the North American Bison: Conceiving Long-Term, Large-Scale Conservation of Wildlife 总被引:2,自引:0,他引:2
ERIC W. SANDERSON KENT H. REDFORD BILL WEBER KEITH AUNE DICK BALDES JOEL BERGER † DAVE CARTER CHARLES CURTIN JAMES DERR STEVE DOBROTT EVA FEARN CRAIG FLEENER STEVE FORREST CRAIG GERLACH C. CORMACK GATES JOHN E. GROSS PETER GOGAN SHAUN GRASSEL JODI A. HILTY MARV JENSEN KYRAN KUNKEL DUANE LAMMERS RURIK LIST KAREN MINKOWSKI TOM OLSON CHRIS PAGUE PAUL B. ROBERTSON BOB STEPHENSON 《Conservation biology》2008,22(2):252-266
Abstract: Many wide-ranging mammal species have experienced significant declines over the last 200 years; restoring these species will require long-term, large-scale recovery efforts. We highlight 5 attributes of a recent range-wide vision-setting exercise for ecological recovery of the North American bison ( Bison bison ) that are broadly applicable to other species and restoration targets. The result of the exercise, the Vermejo Statement on bison restoration, is explicitly (1) large scale, (2) long term, (3) inclusive, (4) fulfilling of different values, and (5) ambitious. It reads, in part, Over the next century, the ecological recovery of the North American bison will occur when multiple large herds move freely across extensive landscapes within all major habitats of their historic range, interacting in ecologically significant ways with the fullest possible set of other native species, and inspiring, sustaining and connecting human cultures. We refined the vision into a scorecard that illustrates how individual bison herds can contribute to the vision. We also developed a set of maps and analyzed the current and potential future distributions of bison on the basis of expert assessment. Although more than 500,000 bison exist in North America today, we estimated they occupy <1% of their historical range and in no place express the full range of ecological and social values of previous times. By formulating an inclusive, affirmative, and specific vision through consultation with a wide range of stakeholders, we hope to provide a foundation for conservation of bison, and other wide-ranging species, over the next 100 years. 相似文献
25.
Biodiversity conservation has been criticized for undermining or ignoring social well‐being. Currently efforts to mutually promote social justice, rural development, and biodiversity conservation, which have been contentious and yielded mixed results, continue to spread despite a general dearth of effective management strategies. We contend that social and economic concerns should be integral to conservation planning and propose that the scale of these phenomena is also critical. To evaluate the merit of this proposal, we adopted and expanded a conservation management strategy framework developed by Joel Heinen and examined how population density, economic disparity, and ethnic heterogeneity vary spatially surrounding 2 contrasting protected areas in East Africa: Kibale National Park in Uganda and Tarangire National Park in Tanzania. Analyses of demographic, wealth, and ethnicity data from regional censuses and household surveys conducted in 2009 and 2010 indicated that choice of scale (landscape or community) changed the management strategies recommended by the model. Therefore, “several small” people?park management strategies varying around a given protected area may be more appropriate than a “single large” people–park strategy applied across an entire protected area. Correspondingly, scale adjusted Heinen recommendations offered new strategies for effective conservation management within these human landscapes not incorporated in current in situ management plans. Uso de Varias Políticas Pequeñas o una Única Política Mayor como Estrategias para Manejar las Interacciones Gente – Parque 相似文献
26.
The Last Mile: How to Sustain Long-Distance Migration in Mammals 总被引:8,自引:0,他引:8
JOEL BERGER 《Conservation biology》2004,18(2):320-331
27.
KELSEY J. RIPP MELANIE BERGER JANE CHEN JUSTIN DITTMEIER MAGGIE GOTER STEPHEN T. MCGARVEY ELIZABETH RYAN 《Conservation biology》2013,27(6):1378-1388
At local scales, infectious disease is a common driver of population declines, but globally it is an infrequent contributor to species extinction and endangerment. For species at risk of extinction from disease important questions remain unanswered, including when does disease become a threat to species and does it co‐occur, predictably, with other threats? Using newly compiled data from the International Union for Conservation of Nature (IUCN) Red List, we examined the relative role and co‐occurrence of threats associated with amphibians, birds, and mammals at 6 levels of extinction risk (i.e., Red List status categories: least concern, near threatened, vulnerable, endangered, critically endangered, and extinct in the wild/extinct). We tested the null hypothesis that the proportion of species threatened by disease is the same in all 6 Red List status categories. Our approach revealed a new method for determining when disease most frequently threatens species at risk of extinction. The proportion of species threatened by disease varied significantly between IUCN status categories and linearly increased for amphibians, birds, and all species combined as these taxa move from move from least concern to critically endangered. Disease was infrequently the single contributing threat. However, when a species was negatively affected by a major threat other than disease (e.g., invasive species, land‐use change) that species was more likely to be simultaneously threatened by disease than species that had no other threats. Potential drivers of these trends include ecological factors, clustering of phylogenetically related species in Red List status categories, discovery bias among species at greater risk of extinction, and availability of data. We echo earlier calls for baseline data on the presence of parasites and pathogens in species when they show the first signs of extinction risk and arguably before. La Amenaza de Enfermedades Incrementa a Medida que las Especies se Aproximan a la Extinción 相似文献
28.
Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems. 相似文献
29.
Greater Yellowstone's Native Ungulates: Myths and Realities 总被引:1,自引:0,他引:1
JOEL BERGER 《Conservation biology》1991,5(3):353-363