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11.
2011年利用样线法对长江上游向家坝库区夏、秋季鸟类进行了实地考察,共记录110种鸟类,隶属15目39科。通过5个调查点、2个对照点不同生境鸟类的多样性研究发现:(1)夏、秋季库区不同生境鸟类的Shannon Wiener 指数较低,几乎均未超过1.5,鸟类物种多样性相对贫乏;(2)库区各生境鸟类Pielou指数均超过了0.75,说明库区环境虽以人工植被为主,但并不单调;(3)阶地疏林灌丛、竹林与常绿落叶阔叶混交林的鸟类相似性差异最小〖JP2〗,而二者与芦苇、荩草丛滩地的差异最大,库区鸟类在不同生境中的分布存在着显著不同。在上述研究的基础上,从物种多样性和河流景观保护的角度,对库区鸟类的不同生境类型进行多要素综合分析,结果显示: 山地森林生境的物种多样性相对丰富,生态价值最高,而河滩和阶地疏林灌丛、竹林生境具备一定的景观特色,也有相当的生态价值  相似文献   
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Between 1998 and 2005, specific features of spatiotemporal distribution of small mammals in transformed habitats were studied using the example of the bank vole living in a gradient of chemical environmental pollution (the Middle Urals). Technogenic degradation of spruce-fir forests proved to entail significant changes in the spatial structure and abundance of vole populations. Differences in colonization of disturbed and intact territories by bank voles at different stages of population dynamics were revealed.  相似文献   
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Density and nutritional condition of the five carabid beetle species Agonum mülleri, Anchomenus dorsalis, Anisodactylus binotatus, Pterostichus vernalis and Poecilus cupreus was studied. Carabids were caught in sixteen 1–4-year-old wildflower areas, identified and counted, their nutritional condition was calculated and calculations were related to habitat parameters (i.e. wildflower area age, vegetation cover, soil water content, habitat size, surrounding landscape composition) and sex.Whereas the number of Anisodactylus binotatus caught responded positively to succession in wildflower areas, A. mülleri numbers tended to decrease and the other three species were unaffected. In a stepwise multiple regression species affiliation, sex and age of wildflower area explained together 98.5% of the variance in the pooled nutritional condition of Anchomenus dorsalis, Anisodactylus binotatus, A. mülleri and P. vernalis. Age of wildflower area alone explained 61.7% of the variance and age increased the nutritional condition of carabids. Correspondingly, nutritional condition of Poecilus cupreus was positively correlated with the age of wildflower area. Overall, the nutritional condition of the carabid assemblage studied increased from the first to the second year and then remained stable. To keep the proportion of 1-year-old wildflower areas low, wildflower areas should therefore be maintained for several years to improve the life conditions of carabid beetles and to enhance their beneficial effects in agroecosystems.  相似文献   
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Effects of New Forestry Practices on Rare Epiphytic Macrolichens   总被引:5,自引:0,他引:5  
Abstract:  The preservation of key habitats is included in modern forest-management practices as one of the main means to preserve biodiversity in northern European production forests. I examined the distribution patterns and persistence of occurrence of rare epiphytic macrolichens in a predominantly unprotected forest landscape with an area of 278 km2 in southern Finland. Occurrence data of macrolichens in two key habitats, rock outcrops and mires, were compared with data from production forests. The density of populations of rare macrolichens was 50-fold higher on rock outcrops and 25-fold higher on mires than in production forests. Most rare species of epiphytic macrolichens were found only in key habitats. In modern, intensively managed forest landscapes, rock outcrops appeared to represent the main habitats for rare macrolichens as a result of the long-term continuity of old trees. Most macrolichen occurrences represented very small populations with a high extinction risk. Of the populations found in 1989–1995 in key habitats, 51% had disappeared, by 2000–2001, mainly as a result of forestry activities. The disappearance of populations significantly exceeded the rate of establishment of new populations. My results emphasize the importance of key habitats for declining forest species. There is also a need to improve and sharpen the guidelines for delimiting and managing key habitats in order to halt the continued decline of epiphytic macrolichens.  相似文献   
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Abstract:  The area of Caricion davallianae alliance in Switzerland has been considerably reduced and fragmented during the last 150 years. We assessed the genetic variability, inbreeding level, and among-population differentiation of two common habitat-specific plant species, Carex davalliana SM. and Succisa pratensis Moench, in 18 Caricion davallianae fen meadows subjected to fragmentation. We used a spatial field design of fen systems (six systems total), each consisting of one large habitat island and two small habitat islands. We used allozyme electrophoresis to derive standard genetic parameters ( A, P, HO, HE, FIS, FST ). In Carex we identified a consistently lower A in isolated habitat islands; furthermore, HE was lower in small habitat islands than in large habitat islands. In Succisa we identified a lower HO in small habitat islands than in larger ones. Small habitat islands were marginally significantly differentiated (  FST ) from large islands for Succisa . For both species, no effects were evident for FIS ; therefore, we argue that genetic drift rather than inbreeding is the main cause of the observed differences. The genetic structure of Carex and Succisa in small habitat islands differed from that in large habitat islands, but differences were small. It appears that the observed differences in genetic variability among fen meadows correspond to observed differences in fitness and demographic traits. We show that habitat fragmentation affects not only the rare species in an ecosystem but also reduces the survival probabilities of common species. One of the main goals of conservation should be to mitigate fragmentation of natural habitats in order to increase population sizes and connectivity.  相似文献   
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The dynamics of habitat distribution in two bird species differing in the level of site tenacity—willow warbler (relatively tenacious) and little bunting (more flexible)—were studied at the boundary of the northern taiga and forest–tundra zones over ten years. The distribution pattern proved to be more uniform in the willow warbler than in the little bunting. Both species occupied their habitats according to a well-known scheme: initially, the birds settled in their favorable floodplain habitats and later; when their abundance increased, in less preferable habitats (terraces above the floodplain, moss bogs, and the tundra). In the case of willow warbler, the process of occupying the floodplain was stepwise: bird density increased sharply, remained at the same level in the next year, then increased again, etc. In the case of little bunting, the degree of floodplain occupation by birds remained high, except for the years when high spring floods interfered with bird settling.  相似文献   
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Knowledge and detecting impacts of human activities on the coastal ecosystem is an essential management requirement and also very important for future and proper planning of coastal areas. Moreover, documentation of these impacts can help in increasing public awareness about side effects of unsustainable practices. Analysis of multidate remote sensing data can be used as an effective tool in environmental impact assessment (EIA). Being synoptic and frequent in coverage, multidate data from Landsat and other satellites provide a reference record and bird’s eye viewing to the environmental situation of the coastal ecosystem and the associated habitats. Furthermore, integration of satellite data with field observations and background information can help in decision if a certain activity has caused deterioration to a specific habitat or not. The present paper is an attempt to utilize remote sensing data for assessment impacts of some human activities on the major sensitive habitats of the NW Egyptian Red Sea coastal zone, definitely between Ras Gemsha and Safaga. Through multidate change analysis of Landsat data (TM & ETM+ sensors), it was possible to depict some of the human infringements in the area and to provide, in some cases, exclusive evidences for the damaging effect of some developmental activities.  相似文献   
19.
We evaluated performance of species distribution models for predictive mapping, and how models can be used to integrate human pressures into ecological and economic assessments. A selection of 77 biological variables (species, groups of species, and measures of biodiversity) across the Baltic Sea were modeled. Differences among methods, areas, predictor, and response variables were evaluated. Several methods successfully predicted abundance and occurrence of vegetation, invertebrates, fish, and functional aspects of biodiversity. Depth and substrate were among the most important predictors. Models incorporating water clarity were used to predict increasing cover of the brown alga bladderwrack Fucus vesiculosus and increasing reproduction area of perch Perca fluviatilis, but decreasing reproduction areas for pikeperch Sander lucioperca following successful implementation of the Baltic Sea Action Plan. Despite variability in estimated non-market benefits among countries, such changes were highly valued by citizens in the three Baltic countries investigated. We conclude that predictive models are powerful and useful tools for science-based management of the Baltic Sea.  相似文献   
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