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131.
Cristina Zago Gabriele Capodaglio Carlo Barbante Michele Giani Ivo Moret Giuseppe Scarponi Paolo Cescon 《Chemistry and Ecology》2002,18(1):39-51
In the present study the concentrations of cobalt, copper, iron, manganese, zinc were analysed and the speciation of copper and zinc performed, with a summer and winter sampling, for two areas in the Northern Adriatic Sea and crossing at the farthest zones of the Po river-sea water interface. Results show that when salinity increases the concentrations of all investigated metals (with the exception of cobalt) present some degree of biogeochemical cycling. Copper is the element whose dissolved phase has the highest importance in metal transport across the salinity gradient. Results of speciation analysis demonstrate that the presence of excess amounts (5-8 fold) of unbound ligands confers a buffering capacity for potential inputs of dissolved metals into the Northern Adriatic Sea. The speciation of both copper and zinc in the dissolved phase was dominated by organic complexation. 相似文献
132.
三峡水库支流回水区富营养化时空分布特征 总被引:5,自引:0,他引:5
为了解三峡水库175m水位蓄水后库区支流回水区富营养化现状,探索支流回水区富营养化时空变化规律,在三峡库区支流回水区开展了富营养化普查和监测。结果表明,库区支流总磷浓度为0.035~0.65 mg/L,平均浓度为0.157 mg/L,总氮浓度为0.681~5.690 mg/L,平均浓度为2.037mg/L,远远高于湖库水体出现富营养化的总磷和总氮临界浓度0.02、0.2 m g/L,库区支流营养盐条件适宜藻类生长。在每年4~9月的春季、盛夏和夏秋之交的非暴雨时段,当气温和光照适宜,支流回水核心区富营养化现象明显,出现藻类"疯长"的水华现象,但受气温变化影响明显,库区的富营养化现象仍是间歇的,局部的。 相似文献
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Though studies have modeled the effects of fires on elk, no studies have related the effects of post-fire landscape succession on ungulate movements and distribution using dynamic modeling techniques. The purpose of this study was to develop and test a spatially-explicit, stochastic, individual-based model (IBM) to evaluate potential movement and distribution patterns of elk (Cervus elaphus nelsoni) in relation to spatial and temporal aspects of the Cerro Grande Fire that burned north central New Mexico in May of 2000. Following extensive literature review, the SAVANNA Ecosystem Model was selected to simulate the underlying post-fire successional processes driving elk movement and distribution. Standard logisitic regression was used to analyze habitat-use patterns of ten elk from data collected using global positioning system radio collars while an additional five animals were used as an independent test set during model validation. Static variables in the form of roads, buildings, fences, and habitual use/memory were used to modify a map of impedance values based on the logistic regression of slope, aspect, and elevation. Integration with SAVANNA came through the application of a habitat suitability index (HSI), which combined movement rules written for the IBM and variables modified and produced by the dynamic ecological processes run in SAVANNA. Overall pattern analysis indicated that realistic migrational processes and habitat-use patterns emerged from movement rules incorporated into the IBM in response to advancing and receding snow when compared to the independent test set. Primary and secondary movement pathways emerged from the collective responses of simulated individuals. Using regression analyses, no significant differences between simulated animals and animals used in either model development or an independent test set revealed any differences in response to snow patterns. These considerations suggest the model was adequately corroborated based on existing data and outlined objectives. 相似文献
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Peng Hu Changsheng Guo Yan Zhang Jiapei Lv Yuan Zhang Jian Xu 《Frontiers of Environmental Science & Engineering》2019,13(4):56
139.
Economic Development,Income Inequality and Environmental Degradation of Fisheries Resources in Mauritius 总被引:1,自引:0,他引:1
Sobhee SK 《Environmental management》2004,34(1):150-157
This article examines how environmental degradation of fisheries resources in the context of Mauritius is linked up with human investment in education, economic growth, and income inequality. Empirical evidence shows that public-sector investment in education promotes economic growth, but at the expense of greater inequality of income. Among the vulnerable groups affected by this type of development process lies the fisherman community. In fact, children of poor families in coastal Mauritius have constrained access to complete school education because of the persistently high opportunity cost involved. Hence, this community is caught up in a vicious circle, as its children or grandchildren would barely be redeployed elsewhere other than in the fisheries sector itself. Such exclusion might account for the overexploitation of marine resources of the island and the accompanying reduction in fish catch over recent years.*(Paper presented at the Third Research and Training Workshop of the Resource Accounting Network for Eastern and Southern Africa (RANESA), University of Pretoria (Funded by SIDA, Sweden), held in Mauritius, Nov 2000. I am grateful to the participants for their helpful suggestions. Needless to say, the usual disclaimer applies).
Published online 相似文献
140.
A new method for predicting vegetation distributions using decision tree analysis in a geographic information system 总被引:4,自引:0,他引:4
Decision tree analysis was used to predict the distribution of forest communities in an area on the south coast of New South
Wales, Australia. The analysis was carried out using a geographical information system environmental data base of those topographic
and geological variables thought to influence the distribution of vegetation and derived from cartographic sources. The resulting
maps of forest communities are of a resolution sufficient to delimit individual forest stands and contain much ecological
information. 相似文献