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STUART E. MARSH CHARLES F. HUTCHINSON ERIC E. PFIRMAN SHARON A. DES ROSIERS CAMILLE VAN DER HARTEN 《Disasters》1994,18(2):117-129
Beginning in 1990, the University of Arizona, Arizona Remote Sensing Center (ARSC) has been involved in a collaborative effort with the Global Information and Early Warning System (GIEWS) and the Remote Sensing Center of the Food and Agriculture Organization (FAO) of the United Nations in designing and developing an integrated computer workstation for famine early warning. The goal of the project is to provide food security analysts with a set of computer tools to manage a very large and diverse set of data for predicting the onset of food security emergencies for every country on Earth. The initial stage of the project involved the conceptual definition of system elements and the development of overall system architecture. We are now developing an open, flexible, and portable system designed to significantly assist the work of the analysts. System architecture provides a task-specific and user-friendly graphic user interface (GUI) within a Windows environment that will link image processing, geographic information system (GIS), spreadsheet, text, and graphics software packages into a single operational environment. A relational database management system (RDBMS) is serving as the back-end of the workstation to facilitate data storage and retrieval and as a means to preserve analysis methodologies. 相似文献
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As a result of the current decline of oil prices, exploration decisions are more carefully analysed than ever before. At the same time various governments have introduced incentives to reinvest in exploration and development in order to maintain or increase activity. As a result, most exploration decisions are now being analysed as "incremental investments". This has the effect of "trapping" investments in areas where profits are currently being made. This in turn creates serious problems for those developing countries which would like to attract exploration. The paper analyses issues related to sliding scale formulae based on the ROR, and the economic impact of the size of the area to which fiscal terms apply. 相似文献
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The hydrogeomorphic (HGM) approach to wetland classification and functional assessment is becoming more widespread in the
United States but its use has been limited by the length of time needed to develop appropriate data sets and functional assessment
models. One particularly difficult aspect is the transferability among geographic regions of specific models used to assess
wetland function. Sharing of models could considerably shorten development and implementation of HGM throughout the United
States and elsewhere. As hydrology is the driving force behind wetland functions, we assessed the comparability of hydrologic
characteristics of three HGM subclasses (slope, headwater floodplain, mainstem floodplain) using comparable long-term hydrologic
data sets from different regions of the United States (Ridge and Valley Province in Pennsylvania and the Willamette Valley
in Oregon). If hydrology by HGM subclass were similar between different geographic regions, it might be possible to more readily
transfer extant models between those regions. We found that slope wetlands (typically groundwater-driven) had similar hydrologic
characteristics, even though absolute details (such as depth of water) differed. We did not find the floodplain subclasses
to be comparable, likely due to effects of urbanization in Oregon, regional differences in soils and, perhaps, climate. Slight
differences in hydrology can shift wetland functions from those mediated by aerobic processes to those dominated by anaerobic
processes. Functions such as nutrient cycling can be noticeably altered as a result. Our data suggest considerable caution
in the application of models outside of the region for which they were developed. 相似文献
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Bogaert J Salvador-Van Eysenrode D Impens I Van Hecke P 《Environmental management》2001,27(4):493-500
A method is proposed to quantify disturbance impact on isolated habitats. For every landscape patch, the breakpoint distance,
defined as the penetration distance for which equality of interior and edge habitat is observed, can be calculated. Disturbance
with equal impact at all patch sides is assumed. Effects of patch compactness, size, convolution, and perforation are discussed.
The potential use of the measure for nature reserve design is discussed. The breakpoint distance follows the reserve design
guidelines for individual patches, based on island biogeography and is consistent with the form and function principle. A
large breakpoint distance is preferred for natural habitats. Small size, small compactness, intense convolution, and the occurrence
of many gaps depress the breakpoint distance. 相似文献
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Abstract: The traditional environmental Kuznets curve (EKC) hypothesis postulates that environmental degradation follows an inverted U-shaped relationship with gross domestic product (GDP) per capita. We tested the EKC hypothesis with bird populations in 5 different habitats as environmental quality indicators. Because birds are considered environmental goods, for them the EKC hypothesis would instead be associated with a U-shaped relationship between bird populations and GDP per capita. In keeping with the literature, we included other variables in the analysis—namely, human population density and time index variables (the latter variable captured the impact of persistent and exogenous climate and/or policy changes on bird populations over time). Using data from 9 Canadian provinces gathered over 37 years, we used a generalized least-squares regression for each bird habitat type, which accounted for the panel structure of the data, the cross-sectional dependence across provinces in the residuals, heteroskedasticity, and fixed- or random-effect specifications of the models. We found evidence that supports the EKC hypothesis for 3 of the 5 bird population habitat types. In addition, the relationship between human population density and the different bird populations varied, which emphasizes the complex nature of the impact that human populations have on the environment. The relationship between the time-index variable and the different bird populations also varied, which indicates there are other persistent and significant influences on bird populations over time. Overall our EKC results were consistent with those found for threatened bird species, indicating that economic prosperity does indeed act to benefit some bird populations. 相似文献
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Abstract: A drastic decline in the number of black rhinoceroses ( Diceros bicornis ), primarily as a result of poaching places this species in imminent danger of extinction. The remaining black rhinos are divided into small, isolated populations that are vulnerable to demographic extinction, disease epidemics, genetic drift and inbreeding. Some conservationists have suggested minimizing these threats by moving as many animals as possible from different isolated populations to a few safe "rhino sanctuaries." To examine the possible long-term genetic consequences of such a strategy, we focused our efforts on determining the level of genetic differences among the remaining black rhino populations by examining restriction fragment length polymorphisms of the rapidly evolving mitochondrial DNA molecule. The 23 black rhinos in our survey, including animals from three geographic regions and two named subspecies, showed very little mitochondrial DNA differentiation. Only 4 out of 18 restriction enzymes revealed any mtDNA polymorphism, and the average estimated percent sequence divergence between the four mtDNA genotypes observed as 0.17%. Mitochondrial DNA divergence between the two named subspecies, D. b. minor and D. b. michaeli , was estimated to be only 0.29%. These results indicate a very close genetic relationship among the black rhinos in our survey. Thus, the mitochondrial DNA data suggest that within national boundaries, the black rhino populations we sampled may be considered single populations for breeding purposes, which might increase the species' probability of survival. 相似文献
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Abstract: Hydrothermal vents are deep‐sea ecosystems that are almost exclusively known and explored by scientists rather than the general public. Continuing scientific discoveries arising from study of hydrothermal vents are concommitant with the increased number of scientific cruises visiting and sampling vent ecosystems. Through a bibliometric analysis, we assessed the scientific value of hydrothermal vents relative to two of the most well‐studied marine ecosystems, coral reefs and seagrass beds. Scientific literature on hydrothermal vents is abundant, of high impact, international, and interdisciplinary and is comparable in these regards with literature on coral reefs and seagrass beds. Scientists may affect hydrothermal vents because their activities are intense and spatially and temporally concentrated in these small systems. The potential for undesirable effects from scientific enterprise motivated the creation of a code of conduct for environmentally and scientifically benign use of hydrothermal vents for research. We surveyed scientists worldwide engaged in deep‐sea research and found that scientists were aware of the code of conduct and thought it was relevant to conservation, but they did not feel informed or confident about the respect other researchers have for the code. Although this code may serve as a reminder of scientists’ environmental responsibilities, conservation of particular vents (e.g., closures to human activity, specific human management) may effectively ensure sustainable use of vent ecosystems for all stakeholders. 相似文献
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Biodiversity and Conservation of Plants in Brazil 总被引:4,自引:1,他引:3
ANA MARIA GIULIETTI§ RAYMOND M. HARLEY† LUCIANO PAGANUCCI DE QUEIROZ MARIA DAS GRAÇAS LAPA WANDERLEY‡ CASSIO VAN DEN BERG 《Conservation biology》2005,19(3):632-639
Abstract: With more than 56,000 species (excluding fungi), Brazil has one of the richest floras in the world—nearly 19% of the world flora. Our knowledge of the diversity and status of nonvascular plants in Brazil is still fragmentary, although localized studies on algae have revealed loss of species resulting from environmental pollution. Emphasis on local floral surveys, rather than wider taxonomic studies, has obscured estimates of national totals for most taxonomic groups. Knowledge of angiosperms, especially monocotyledons (of which 45% of the species are endemic), is more complete than most. For this group figures are more reliable, with some distribution patterns, endemism levels, and centers of diversity identified. Much, however, still awaits discovery. Coordinated efforts to catalog Brazil's flora are in progress and include projects such as the conservation priority-setting workshops of the Brazilian Ministry of the Environment, which have identified key conservation areas in the major biomes; development of threatened species lists for plants; and the assembly of type data on species of northeastern Brazil through the Darwin Initiative—all of which greatly assist in increasing our knowledge. These initiatives also underline the urgent need to expand the numbers and geographic spread of projects on plant systematics and taxonomy in Brazil, a measure that demands adequate provision of funding and training programs for plant specialists. Finally, Brazil's environmental agency (IBAMA) could play a proactive role in opening protected areas under its jurisdiction, thereby facilitating botanical research by university departments and research institutes. 相似文献
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