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ANDREW S. PULLIN RÁS BÁLDI†§§ OZGUN EMRE CAN‡ MARTIN DIETERICH§ VASSILIKI KATI BARBARA LIVOREIL†† GABOR LÖVEI‡‡ BARBARA MIHÓK§§ OWEN NEVIN NURIA SELVA††† ISABEL SOUSA-PINTO‡‡‡ 《Conservation biology》2009,23(4):818-824
Abstract: Europe is one of the world's most densely populated continents and has a long history of human-dominated land- and seascapes. Europe is also at the forefront of developing and implementing multinational conservation efforts. In this contribution, we describe some top policy issues in Europe that need to be informed by high-quality conservation science. These include evaluation of the effectiveness of the Natura 2000 network of protected sites, implications of rapid economic and subsequent land-use change in Central and Eastern Europe, conservation of marine biodiversity and sustainability of fisheries, the effect of climate change on movement of species in highly fragmented landscapes, and attempts to assess the economic value of ecosystem services and biodiversity. Broad policy issues such as those identified are not easily amenable to scientific experiment. A key challenge at the science–policy interface is to identify the research questions underlying these problem areas so that conservation science can provide evidence to underpin future policy development . 相似文献
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桑沟湾和胶州湾夏季的沉积物-水界面营养盐通量研究 总被引:15,自引:4,他引:15
1999年8月通过原样培养研究了黄海的桑沟湾和胶州湾潮下带沉积物-海水界面的营养盐通量.结果表明,两个湾的沉积物均向水层释放NH4-N,通量为0.76(桑沟湾)和0.67 mmol/m2·d(胶州湾),对水层初级生产所需无机氮的贡献为14%(桑沟湾)和12%(胶州湾);桑沟湾的沉积物对PO4-P有净吸收,通量为-1.17mmol/m2·d,而胶州湾的沉积物释放PO4-P,通量为0.01 mmol/m2·d.与其他近岸浅海环境相比,桑沟湾和胶州湾的沉积物-水界面营养盐通量及对水层初级生产的贡献率均处于较低水平.回归统计分析表明,桑沟湾和胶州湾沉积物-水界面的NH4-N通量与沉积物表层的C、N含量正相关,PO4-P通量与沉积物耗氧率和上覆水PO4-P浓度相关. 相似文献
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MARTIN O. C. KURSTEN 《Natural resources forum》1983,7(1):71-79
Metallic and other mineral resources can contribute powerfully to development. They have to be surveyed and assessed in a systematic way to provide the basis for decisions. Development is seen as a complex network of interrelating factors, which at best can cross-fertilize each other but more often tend to slow down one another. Economics, and especially the availability and cost of energy, are crucial for developing mineral resources.
Les ressources métalliques et autres ressources minières peuvent contribuer d'une manière significative au développement d'un pays. On doit procéder à leur inventaire et leur évaluation d'une façon systématique afin qu'elles fournissent une base sur laquelle peuvent être fondées des décisions. Le développement est perçu comme un réseau complexe de facteurs interdépendants qui au mieux peuvent se renforcer mais qui, le plus souvent, tendent à se ralentir. En particulier, la disponibilitè et le coût de l'énergie représentent des facteurs décisifs dans le développement des ressources minières.
Los recursos minerales metélicos y no metálicos constituyen un factor que pueden tener una gran contribución al desarrollo económico. Este desarrollo es el resultado de un sistema complejo de factores interrelacionados que en el mejor de los casos pueden influir positivamente los unos en los otros pero que a menudo tienden a anularse mutuamente. El costo y disponibilidad de la energía es importante para el desarrollo de recursos naturales. Es también importante la sistemática exploración y evaluación de estos recursos 相似文献
Les ressources métalliques et autres ressources minières peuvent contribuer d'une manière significative au développement d'un pays. On doit procéder à leur inventaire et leur évaluation d'une façon systématique afin qu'elles fournissent une base sur laquelle peuvent être fondées des décisions. Le développement est perçu comme un réseau complexe de facteurs interdépendants qui au mieux peuvent se renforcer mais qui, le plus souvent, tendent à se ralentir. En particulier, la disponibilitè et le coût de l'énergie représentent des facteurs décisifs dans le développement des ressources minières.
Los recursos minerales metélicos y no metálicos constituyen un factor que pueden tener una gran contribución al desarrollo económico. Este desarrollo es el resultado de un sistema complejo de factores interrelacionados que en el mejor de los casos pueden influir positivamente los unos en los otros pero que a menudo tienden a anularse mutuamente. El costo y disponibilidad de la energía es importante para el desarrollo de recursos naturales. Es también importante la sistemática exploración y evaluación de estos recursos 相似文献
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Damgaard CHRISTIAN Hojer RIKKE Bayley MARK Scott-Fordsmand JANECK J. Holmstrup MARTIN 《Environmental and Ecological Statistics》2002,9(2):195-200
A method is presented for modeling the effect of two stresses on mortality. The model assumes a multiplicative simple two-parameter dose-response curve relationship between mortality and the two factors as well as for the effect of combining the two factors. The dose-response curve is modified in order to model survival probabilities. It is shown that the model adequately describes mortality data of Folsomia candida (Collembola) in a two-stress factor design. 相似文献
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Importance of Well-Designed Monitoring Programs for the Conservation of Endangered Species: Case Study of the Snail Kite 总被引:1,自引:0,他引:1
Abstract: Monitoring natural populations is often a necessary step to establish the conservation status of species and to help improve management decisions. Nevertheless, many monitoring programs do not effectively address primary sources of variability in monitoring data, which ultimately may limit the utility of monitoring in identifying declines and improving management. To illustrate the importance of taking into account detectability and spatial variation, we used a recently proposed estimator of abundance (superpopulation estimator) to estimate population size of and number of young produced by the Snail Kite ( Rostrhamus sociabilis plumbeus ) in Florida. During the last decade, primary recovery targets set by the U.S. Fish and Wildlife Service for the Snail Kite that were based on deficient monitoring programs (i.e., uncorrected counts) were close to being met (by simply increasing search effort during count surveys). During that same period, the Snail Kite population declined dramatically (by 55% from 1997 to 2005) and the number of young decreased by 70% between 1992–1998 and 1999–2005. Our results provide a strong practical case in favor of the argument that investing a sufficient amount of time and resources into designing and implementing monitoring programs that carefully address detectability and spatial variation is critical for the conservation of endangered species. 相似文献
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Planting History and Propagule Pressure as Predictors of Invasion by Woody Species in a Temperate Region 总被引:7,自引:0,他引:7
Abstract: We studied 28 alien tree species currently planted for forestry purposes in the Czech Republic to determine the probability of their escape from cultivation and naturalization. Indicators of propagule pressure (number of administrative units in which a species is planted and total planting area) and time of introduction into cultivation were used as explanatory variables in multiple regression models. Fourteen species escaped from cultivation, and 39% of the variance was explained by the number of planting units and the time of introduction, the latter being more important. Species introduced early had a higher probability of escape than those introduced later, with more than 95% probability of escape for those introduced before 1801 and <5% for those introduced after 1892. Probability of naturalization was more difficult to predict, and eight species were misclassified. A model omitting two species with the largest influence on the model yielded similar predictors of naturalization as did the probability of escape. Both phases of invasion therefore appear to be driven by planting and introduction history in a similar way. Our results demonstrate the importance of forestry for recruitment of invasive trees. Six alien forestry trees, classified as invasive in the Czech Republic, are currently reported in nature reserves. In addition, forestry authorities want to increase the diversity of alien species and planting area in the country. 相似文献
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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
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Global Warming, Human Population Pressure, and Viability of the World's Smallest Butterfly 总被引:1,自引:0,他引:1
Abstract: The effects of climate change and habitat destruction and their interaction are likely to be the greatest challenge to animal and plant conservation in the twenty-first century. We used the world's smallest butterfly, the Sinai baton blue ( Pseudophilotes sinaicus ), as an exemplar of how global warming and human population pressures may act together to cause species extinctions. We mapped the entire global range of this butterfly and obtained extensive data on the intensity of livestock grazing. As with an increasing number of species, it is confined to a network of small habitat patches and is threatened both by indirect human-induced factors (global warming) and by the direct activities of humans (in this case, livestock grazing and collection of medicinal plants). In the absence of global warming, grazing, and plant collection, our model suggested that the butterfly will persist for at least 200 years. Above a threshold intensity of global warming, the chance of extinction accelerated rapidly, implying that there may be an annual average temperature, specific to each endangered species, above which extinction becomes very much more likely. By contrast, there was no such threshold of grazing pressure—the chance of extinction increased steadily with increasing grazing. The impact of grazing, however, decreased with higher levels of year-to-year variation in habitat quality. The effect of global warming did not depend on the future level of grazing, suggesting that the impacts of global warming and grazing are additive. If the areas of habitat patches individually fall below certain prescribed levels, the butterfly is likely to go extinct. Two patches were very important for persistence: if either were lost the species would probably go extinct. Our results have implications for the conservation management of all species whose habitats are at risk because of the direct activities of humans and in the longer term because of climate change. 相似文献