甘肃甘南藏族自治州生态环境现状与恢复对策

甘南藏族自治州生态环境状况,对于保障黄河、长江中下游地区生态安全具有重要作用。受多种因素影响,该地区生态环境受到严重破坏。在资料查阅、实地考察与访谈的基础上,阐述了甘南藏族自治州生态环境的现状,分析了产生这种现状的原因,最后提出了重建对策。     

Present State and Future Perspectives of Prostaglandins as a Differentiation Factor in Motor Neurons

Spinal motor neurons have the longest axons that innervate the skeletal muscles of the central nervous system. Motor neuron diseases caused by spinal motor neuron cell death are incurable due to the unique and irreplaceable nature of their neural circuits. Understanding the mechanisms of neurogenesis, neuritogenesis, and synaptogenesis in motor neurons will allow investigators to develop new in vitro models and regenerative therapies for motor neuron diseases. In particular, small molecules can directly reprogram and convert into neural stem cells and neurons, and promote neuron-like cell differentiation. Prostaglandins are known to have a role in the differentiation and tissue regeneration of several cell types and organs. However, the involvement of prostaglandins in the differentiation of motor neurons from neural stem cells is poorly understood. The general cell line used in research on motor neuron diseases is the mouse neuroblastoma and spinal motor neuron fusion cell line NSC-34. Recently, our laboratory reported that prostaglandin E₂ and prostaglandin D₂ enhanced the conversion of NSC-34 cells into motor neuron-like cells with neurite outgrowth. Moreover, we found that prostaglandin E₂-differentiated NSC-34 cells had physiological and electrophysiological properties of mature motor neurons. In this review article, we provide contemporary evidence on the effects of prostaglandins, particularly prostaglandin E₂ and prostaglandin D₂, on differentiation and neural conversion. We also discuss the potential of prostaglandins as candidates for the development of new therapeutic drugs for motor neuron diseases.

     

Reflections on Plant and Soil Nematode Ecology: Past,Present and Future

The purpose of this review is to highlight key developments in nematode ecology from its beginnings to where it stands today as a discipline within nematology. Emerging areas of research appear to be driven by crop production constraints, environmental health concerns, and advances in technology. In contrast to past ecological studies which mainly focused on management of plant-parasitic nematodes, current studies reflect differential sensitivity of nematode faunae. These differences, identified in both aquatic and terrestrial environments include response to stressors, environmental conditions, and management practices. Methodological advances will continue to influence the role nematodes have in addressing the nature of interactions between organisms, and of organisms with their environments. In particular, the C. elegans genetic model, nematode faunal analysis and nematode metagenetic analysis can be used by ecologists generally and not restricted to nematologists.     

Science, Art, or Application—the "Karma" of Restoration Ecology

The present state of restoration ecology is far away from Bradshaw’s “acid test for ecology.” The conclusions drawn from the series of papers in this issue and from the Jena workshop suggest some directions in which the field may progress. More attention must be paid to the degraded state, which should be evaluated by its specific features and carefully analyzed before any restoration plan is laid down. Restoration goals have to be realistic, which includes the appreciation of globally changing conditions, resulting in a paradigm‐shift toward “forward‐restoration.” Basically, the transition from the degraded state conditions to the target state is a kind of succession that is manipulated by the application of goal‐orientated and system‐specific disturbances. Whenever possible, restorationists should step back and make use of naturally occurring succession, which requires a sophisticated restoration strategy, involving flexible management responses, multiple alternative target states, robust measurements for the restoration progress, and careful long‐term monitoring. The unique feature of restoration ecology is the involvement of socioeconomic decisions, and conceptual frameworks for ecological restoration have to implement the specific links to natural succession. To bridge the gap between ecological theory and on the ground restoration, it is essential that restoration practice is translated into the vocabulary and thinking of basic ecology. If all these aspects are integrated, ecological restoration as an application—and restoration ecology as an applied science—may develop into an acid test for our understanding of interactions between people and their environment, rather than for pure ecology.     

Restoration of living environment based on vegetation ecology: Theory and practice

The foundation of ecological restoration is how to preserve biocoenoses (i.e. functional ecosystems) and how to restore and reconstruct them where they were destroyed. One of the most important challenges is the restoration of complex, multilayer forests representing the potential natural vegetation. Native forests have functions in disaster mitigation and environmental protection, as well as providing the basis of existence for local people and maintaining gene pools for the future. Through vegetation surveys in Japan and South-east Asia, we have established basic principles in vegetation-ecological restoration of forests. We have been restoring expected disaster-mitigation and environmental protection forests, as experimental reforestation projects, since the 1970s at more than 750 sites throughout the 3000km long Japanese Archipelago, and since the 1980s in parts of South-east Asia, China and South America. The restoration movement has spread from a local activity to a global movement. We aim for the sustainable development of human society through ecological restoration of living environments.     

生态学中的干扰理论与应用实例

生态学中的干扰理论与应用实例魏斌张霞吴热风（北京大学环境科学中心,１００８７１）ＴｈｅｏｒｅｔｉｃａｌＡｎａｌｙｓｉｓｏｆＤｉｓｔｕｒｂａｎｃｅｉｎＥｃｏｌｏｇｙａｎｄｉｔｓＡｐｐｌｉｃａｔｉｏｎ．ＷｅｉＢｉｎ,ＺｈａｎｇＸｉａａｎｄＷｕＲｅｆｅｎｇ...     

直接心室辅助致动方法的现状与发展

直接心室辅助通过在心脏外侧柔性挤压心脏,帮助虚弱的心脏恢复功能。它能够避免人工器件与血液接触引发的血栓、血感染等问题,是人工心脏辅助器件研究与开发的重要领域之一。直接心室辅助的致动器,决定了器件的结构、形状、及其性能,是整个辅助器件关键中的关键,致动器上的任何突破有可能对直接心室辅助器件产生革命性影响。因此,本文从致动原理的角度,分析、探讨了直接心室辅助的致动方法及其存在问题,这对探索与开发满足要求的下一代直接心室辅助致动器有一定的帮助作用。     

生态文明——人类未来的文明：关于人与自然持续发展的思考

生态文明人类未来的文明关于人与自然持续发展的思考李建国（中国林业科学研究院林业研究所,北京１０００９１）ＥｃｏｌｏｇｉｃａｌＣｉｖｉｌｉｚａｔｉｏｎｔｈｅＨｕｍａｎＦｕｔｕｒｅＣｉｖｉｌｉｚａｔｉｏｎＣｏｎｓｉｄｅｒａｔｉｏｎａｂｏｕｔＨｕｍａｎｂｅ...     

Application of an Ecological Risk Assessment for Evaluation of Alternatives Considered for Restoration of Oysters in Chesapeake Bay: Background and Approach

Oyster populations in Chesapeake Bay, USA, declined precipitously over the past three decades, and on-going efforts to restore the native oysters to former abundance were considered to be ineffective. Maryland and Virginia natural resource agencies proposed the introduction of a non-native Asian oyster (Crassostrea ariakensis) that is resistant to diseases affecting the native oyster and well adapted to the Chesapeake Bay environment. Numerous stakeholders raised concerns about potential adverse consequences of an introduction of a non-native species into a new environment. In response, state and federal agencies determined that an Environmental Impact Statement (EIS) should be prepared to address the environmental consequences of such an introduction as well as of seven other oyster restoration alternatives, including several involving only the native oyster. Preparation of an Ecological Risk Assessment (ERA) of the proposed action as well as all alternatives was an integral element of EIS preparation. This series of articles describes several different analyses that contributed to and collectively comprised the ERA conducted as input to the EIS. The final article of this series in HERA describes how the ERA and EIS findings were taken into account in the final decision on the preferred restoration alternative by state and federal agencies.     

Geogenically Acidified Mining Lakes — Living Conditions and Possibilities of Restoration

Pyrite and marcasite oxidation in the consequence of lignite surface mining creates lakes with pH as low as 2 to 3, buffered by high contents of iron and aluminium. Living conditions in this extreme habitat for plants and animals are described as well as the characteristics of the pioneer settlement. The utilization of these fish-free lakes is very limited. As possibilities for a water quality improvement special recultivation methods of overburden, chemical neutralization and biological ecotechnologies are recommended.     

Sentinel Nematodes of Land-Use Change and Restoration in Tallgrass Prairie

Changes in land use and the associated changes in land cover are recognized as the most important component of human-induced global change. Much attention has been focused on deforestation, but grasslands are among the most endangered ecosystems on Earth. The North American tallgrass prairie is a dramatic example, exhibiting a greater than 95% decline in historical area. Renewed interest in prairie conservation and restoration has highlighted the need for ecological indicators of disturbance and recovery in native systems, including the belowground component. The tallgrass prairie differs from the agricultural systems that have replaced it in having greater diversity and heterogeneity of resources, less physical soil disturbance (although other disturbances, such as fire and grazing, are prominent), and greater nitrogen limitation. Understanding the responses of nematode taxa to these characteristic differences is crucial to the development and improvement of community indices, but while knowledge of disturbance responses by individual taxa is accumulating, the level of necessary taxonomic resolution remains in question. Although nematode communities generally are better described for temperate grasslands than for other natural ecosystems, identification of sentinel taxa is further confounded by high levels of diversity, and both spatial and temporal heterogeneity.     

露天煤矿废弃地生态重建智能决策支持系统的系统分析与总体设计

大型露天煤矿开采引发的土地退化问题复杂,其废弃地的生态重建更是涉及采矿学、地貌学、农学、林学、生态学、环境学、经济学和社会科学等理论。因而,很难用传统的思维方法、数量化和数学模型的应用及研究工具来解决。建立废弃地生态重建智能决策支持系统（Ｉｎｔｅｌｉ...     

Floodplain connectivity, disturbance and change: a palaeoentomological investigation of floodplain ecology from south-west England

1. Floodplain environments are increasingly subject to enhancement and restoration, with the purpose of increasing their biodiversity and returning them to a more 'natural' state. Defining such a state based solely upon neoecological data is problematic and has led several authors to suggest the use of a palaeoecological approach. 2. Fossil Coleopteran assemblages recovered from multiple palaeochannel fills in south-west England were used to investigate past floodplain and channel characteristics during the mid- to late-Holocene. Ordination of coleopteran data was performed using Detrended Correspondence Analysis (DCA) and produced clear and discrete clustering. This clustering pattern is related to the nature of the environment in which assemblages were deposited and hence channel configuration and dynamics. 3. The DCA clustering pattern is strongly related to measures of ecological evenness, and a strong relationship between these indices and the composition of the water beetle assemblage within samples was revealed. Repeating the ordination with presence-absence data results in a similar pattern of clustering, implying that assemblage composition is crucial in determining cluster placement. 4. As assemblage composition is primarily a function of floodplain topography and hence disturbance regime, we attempt to relate these data to the Intermediate Disturbance Hypothesis (IDH). A significant positive correlation was found between ecological diversity (Shannon's H') and Axis 1 of all ordinations in predominantly aquatic assemblages.     

LCA of Multicrystalline Silicon Photovoltaic Systems - Part 1: Present Situation and Future Perspectives (8 pp)

- Part 1: Present Situation and Future Perspectives Part 2: Application on an Island Economy Goal, Scope and Background Incorporation of exposure and risk concepts into life cycle impact assessment (LCIA) is often impaired by the number of sources and the complexity of site-specific impact assessment, especially when input-output (I-O) analysis is used to evaluate upstream processes. This makes it difficult to interpret LCIA outputs, especially in policy contexts. In this study, we develop an LCIA tool which takes into account the geographical variability in both emissions and exposure, and which can be applied to all economic sectors in I-O analysis. Our method relies on screening-level risk calculations and methods to estimate population exposure per unit of emissions from specific geographic locations. Methods We propose a simplified impact assessment approach using the concept of intake fraction, which is the fraction of a pollutant or its precursor emitted that is eventually inhaled or ingested by the population. Instead of running a complex site-specific exposure analysis, intake fractions allow for the accounting of the regional variability in exposure due to meteorological factors and population density without much computational burden. We calculate sector-specific intake fractions using previously-derived regression models and apply these values to the supply chain emissions to screen for the sectors whose emissions largely contribute to the total exposures. Thus, the analytical steps are simplified by relying on these screening-level risk calculations. We estimate population exposure per unit emissions from specific geographic locations only for the facilities and pollutants that pass an initial screening analysis. We test our analytical approach with reference to the case of increasing insulation for new single-family homes in the US. We quantify the public health costs from increasing insulation manufacturing and compare them with the benefits from energy savings, focusing on mortality and morbidity associated with exposure to primary and secondary fine particles (PM2.5) as well as cancer risk associated with exposure to toxic air pollutants. We estimate health impacts using concentration-response functions from the published literature and compare the costs and benefits of the program by assigning monetary values to the health risks. In the second part of this paper, we present the results of our case study and consider the implications for incorporating exposure and risk concepts into I-O LCA. Conclusions We have presented a methodology to incorporate regional variability in emissions and exposure into input-output LCA, using reduced-form information about the relationship between emissions and population exposure, along with standard input-output analysis and risk assessment methods. The location-weighted intake fractions can overcome the difficulty in incorporation of regional exposure in LCIA.     

General Description of Partly Meromictic Hypertrophic Lake Verevi,its Ecological Status,Changes during the Past Eight Decades,and Restoration Problems

The present study describes generally the ecosystem of Lake Verevi while more detailed approaches are presented in the same issue. The main task of the article is to estimate long-term changes and find the best method for the restoration of good ecological status. Lake Verevi (surface 12.6 ha, mean depth 3.6 m, maximum depth 11 m, drainage area 1.1 km², water exchange 0.63-times per year) is a hypertrophic hard-water lake located in town Elva (6400 inhabitants). Long-term complex limnological investigations have taken place since 1929. The lake has been contaminated by irregular discharge of urban wastewaters from oxidation ponds since 1978, flood from streets, and infiltrated waters from the surrounding farms. The so-called spring meromixis occurred due to extremely warm springs in recent years. The index value of buffer capacity of Lake Verevi calculated from natural conditions is on the medium level. Water properties were analysed according to the requirements of the EU Water Framework Directive. According to the classification, water quality as a long-term average of surface layers is moderate-good, but the water quality of bottom layers is bad. Values in deeper layers usually exceed 20–30 times the calculated reference values by Vighi and Chiaudani’s model. Naturally, at the beginning of the 20th century the limnological type of the lake was moderately eutrophic. During the 1980s and 1990s the ecosystem was out of balance by abiotic characteristics as well as by plankton indicators. Rapid fluctuations of species composition and abundance can be found in recent years. Seasonal variations are considerable and species composition differs remarkably also in the water column. The dominating macrophyte species vary from year to year. Since the annual amount of precipitation from the atmosphere onto the lake surface is several times higher, the impact of swimmers could be considered irrelevant. Some restoration methods were discussed. The first step, stopping external pollution, was completed by damming the inlet. Drainage (siphoning) of the hypolimnetic water is discussed. Secondary pollution occurs because Fe:P values are below the threshold. The authors propose to use phosphorus precipitation and hypolimnetic aeration instead of siphoning.     

Wet meadows of the alliance <Emphasis Type="Italic">Molinion</Emphasis> and their environmental gradients in Slovenia

The main objective of this study was to examine the relationships between wet meadow plant communities of Molinon alliance and their environmental conditions in Slovenia. The ecology of these communities was analysed in detail. The study provides the data on the vegetation and environmental parameters, the significance of parameters for the plant species composition, most important environmental gradients and differences between plant communities. In all plots the vegetation was recorded and soil parameters were analysed (pH, plant-available P and K, N^t, organic C, C/N ratio, exchangeable Ca²⁺, Mg²⁺, K⁺, Na⁺, H⁺, electrical conductivity, base saturation). Other conditions were also considered (e.g., mean annual temperature and precipitation, humidity index, mean Ellenberg moisture and nutrient value) to test possible correlations as well. Vegetation was classified by means of multivariate cluster analysis, while vegetation-site relationships were examined with direct gradient analysis (CCA). Six associations from the Molinon alliance (Selino-Molinietum, Plantagini altissimae-Molinietum, Carici davallianae-Molinietum, Gentiano-Molinietum litoralis, Junco conglomerati-Betonicetum and Sanguisorbo-Festucetum commutatae) were identified and analysed. Soil reaction was identified as most significant environmental parameter explaining the variation of the studied vegetation. There are several statistically significant differences in site conditions between the communities (pH, moisture, nutrient status, Ca²⁺). The studied associations represent clearly defined ecological units.     

Ecology of Mangrove Growth and Recovery in the Lesser Antilles: State of Knowledge and Basis for Restoration Projects

Whereas the increasing knowledge on tropical coastal wetlands highlights the ecological and economical importance of such ecosystems, anthropogenic activities within the coastal zone have caused substantial, irreversible losses of mangrove areas in the Lesser Antilles during the last decades. Such a paradox gives strength to compensatory policy efforts toward mangrove restoration. We review the available knowledge on the ecology of mangrove growth and recovery in the Lesser Antilles as a contribution to possible restoration projects in such islands. Distribution of species follows a general pattern of seaward/landward zonation according to their respective tolerance to flooding and to pore‐water salinity. An experimental study of seedling growth following simulated oil spill has documented the tolerance of Rhizophora mangle and Avicennia germinans seedlings to oil concentration in soils and the effects of natural biotic and abiotic factors on seedlings growth and survival. Monitoring mangrove recovery following hurricane Hugo has given information on growth patterns, from seedling to sapling stages, according to species and site conditions. Forest recovery was mostly due to pre‐established seedlings. For the large Rhizophora propagules, buoyancy appears to be a quite inefficient way of dispersal far inland from the sea shore or riversides. Causes of recovery failure are discussed. From these results we attempt to answer the questions when, where, how to plant mangroves, and what species to use.     

Carbon stocks in above‐ground biomass of monoculture plantations,mixed species plantations and environmental restoration plantings in north‐east Australia

Summary The emergence of carbon markets has provided a potential source of funding for reforestation projects. However, there is concern amongst ecologists that these markets will promote the establishment of monoculture plantations rather than more diverse restoration plantings, on the assumption that fast‐growing monocultures are likely to store more carbon than restoration plantings. We examined the validity of this assumption for three predominantly rainforest plantation types established in the moist tropical uplands of north‐east Australia: monoculture plantations of native rainforest conifers (n = 5, mean age 13 years); mixed species plantations of rainforest cabinet timber species, rainforest conifers and eucalypts (n = 5, mean age 13 years); and, environmental restoration plantings comprised mostly of a diverse range of rainforest trees (n = 10, mean age 14 years). We found that restoration plantings stored significantly more carbon in above‐ground biomass than monoculture plantations of native conifers (on average, 106 t vs 62 t carbon per ha); and tended to store more carbon than mixed species timber plantations which were intermediate in value (86 t carbon per ha). Carbon stocks were higher in restoration plantings than in monoculture and mixed species plantations for three reasons. First, and most importantly, restoration plantings were more densely stocked than monoculture and mixed species plantations. Second, there were more large diameter trees in restoration plantings than monoculture plantations. Third, the trees used in restoration plantings had a higher average wood density than the conifers used in monoculture plantations. While, on average, wood density was higher in mixed species plantations than restoration plantings, the much higher stocking rate of restoration plantings meant they stored more carbon than mixed species plantations. We conclude that restoration plantings in the moist tropics of north‐east Australia can accumulate relatively high amounts of carbon within two decades of establishment. Comparison with reference rainforest sites suggests that restoration plantings could maintain their high stocking rates (and therefore high biomass) as they develop in future decades. However, because restoration plantings are currently much more expensive to establish than monoculture plantations, restoration plantings are unlikely to be favoured by carbon markets. Novel reforestation techniques and designs are required if restoration plantings are to both provide habitat for rainforest biota and store carbon in biomass at a cost comparable to monoculture plantations.