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171.
Most conservation planning to date has focused on protecting today's biodiversity with the assumption that it will be tomorrow's biodiversity. However, modern climate change has already resulted in distributional shifts of some species and is projected to result in many more shifts in the coming decades. As species redistribute and biotic communities reorganize, conservation plans based on current patterns of biodiversity may fail to adequately protect species in the future. One approach for addressing this issue is to focus on conserving a range of abiotic conditions in the conservation‐planning process. By doing so, it may be possible to conserve an abiotically diverse “stage” upon which evolution will play out and support many actors (biodiversity). We reviewed the fundamental underpinnings of the concept of conserving the abiotic stage, starting with the early observations of von Humboldt, who mapped the concordance of abiotic conditions and vegetation, and progressing to the concept of the ecological niche. We discuss challenges posed by issues of spatial and temporal scale, the role of biotic drivers of species distributions, and latitudinal and topographic variation in relationships between climate and landform. For example, abiotic conditions are not static, but change through time—albeit at different and often relatively slow rates. In some places, biotic interactions play a substantial role in structuring patterns of biodiversity, meaning that patterns of biodiversity may be less tightly linked to the abiotic stage. Furthermore, abiotic drivers of biodiversity can change with latitude and topographic position, meaning that the abiotic stage may need to be defined differently in different places. We conclude that protecting a diversity of abiotic conditions will likely best conserve biodiversity into the future in places where abiotic drivers of species distributions are strong relative to biotic drivers, where the diversity of abiotic settings will be conserved through time, and where connectivity allows for movement among areas providing different abiotic conditions.  相似文献   
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173.
This paper describes a comprehensive model of wastewater treatment in secondary facultative ponds, which combines 3D hydrodynamics with a mechanistic water quality model. The hydrodynamics are based on the Navier-Stokes equation for incompressible fluids under shallow water and Boussinesq assumptions capturing the flow dynamics along length, breadth and depth of the pond. The water quality sub model is based on the Activated Sludge Model (ASM) concept, describing COD and nutrient removal as function of bacterial growth following Monod kinetics, except for Escherichia coli removal, which was modelled as first order decay. The model was implemented in the Delft3D software and was used to evaluate the effect of wind and the addition of baffles on the water flow pattern, temperature profiles in the pond and treatment efficiency. In contrast to earlier models reported in the literature, our simulation results did not show any significant improvement in COD removal (based on the ASM concept) with addition of baffles or under intermittent wind-induced mixing. However, E. coli removal efficiency, based on a first order decay approach, showed a fair improvement in the presence of baffles or intermittent wind-induced mixing. Furthermore, simulations with continuous wind effect showed a decrease in removal efficiency for COD but a further increase in E. coli removal efficiency. Such contrasting results for two different approaches in modelling could indicate that the first order decay concept might not be appropriate to describe all the interactions between biochemical processes in a pond. However, these interpretations remain theoretical, as the model needs validation with field data.  相似文献   
174.
This article presents an analysis of the projected performance of urban residential rainwater harvesting systems in the United States (U.S.). The objectives are to quantify for 23 cities in seven climatic regions (1) water supply provided from rainwater harvested at a residential parcel and (2) stormwater runoff reduction from a residential drainage catchment. Water‐saving efficiency is determined using a water‐balance approach applied at a daily time step for a range of rainwater cistern sizes. The results show that performance is a function of cistern size and climatic pattern. A single rain barrel (190 l [50 gal]) installed at a residential parcel is able to provide approximately 50% water‐saving efficiency for the nonpotable indoor water demand scenario in cities of the East Coast, Southeast, Midwest, and Pacific Northwest, but <30% water‐saving efficiency in cities of the Mountain West, Southwest, and most of California. Stormwater management benefits are quantified using the U.S. Environmental Protection Agency Storm Water Management Model. The results indicate that rainwater harvesting can reduce stormwater runoff volume up to 20% in semiarid regions, and less in regions receiving greater rainfall amounts for a long‐term simulation. Overall, the results suggest that U.S. cities and individual residents can benefit from implementing rainwater harvesting as a stormwater control measure and as an alternative source of water.  相似文献   
175.
This paper examines the role of community-based management (CBM) in dealing with the problem of mine water pollution (MWP) in four ex-pit sites in northeast England. The outcomes of CBM can be divided into two categories: ecological (environmental improvement) and social (community improvement). The ecological outcomes range from problem recognition to investigation and remediation; the social outcomes range from community awareness to participation and enhanced cooperation. Both kinds of outcome were completely achieved in only one site (Quaking Houses). In the other three sites, varying degrees of success were achieved in each category. The main lessons learned are two-fold: first, even if CBM does not achieve its ecological aims, it may nonetheless be valuable in achieving social outcomes; second, its chances of achieving either ecological or social outcomes are linked to the resources (human, technical, financial, experiential, structural, legitimacy and network) that the community possesses.  相似文献   
176.
Porencephaly is a rare central nervous system (CNS) abnormality that can be caused by an intraparenchymal destructive process or a developmental defect. Here we report on a prenatal ultrasound diagnosis of complex CNS abnormalities including agenesis of the corpus callosum, agenesis of the cerebellar vermis, bilateral hydrocephaly, and bilateral porencephaly in fetus at 33 weeks' gestation. The diagnosis of familial orofaciodigital syndrome type I (OFD I) was raised after fetal autopsy, clinical examination of the family, and the X-linked dominant inheritance pattern. This is the fourth report of porencephaly in association with OFD I. We discuss the difficulties in genetic counselling since OFD I shows variable expressivity of the phenotypic features. Furthermore, we emphasize the importance of a detailed ultrasound examination after a prenatal diagnosis of porencephaly. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
177.
The EU is committed to combat climate change and to increase security of its energy supply. Bioenergy from forestry and agriculture plays a key role for both. Concurrently, the EU agreed to halt the loss of biodiversity within its member states. To fulfil the biodiversity target more nature conservation and restoration sites need to be designated. There are arising concerns that an increased cultivation of bioenergy crops will decrease the land available for nature reserves and for “traditional” agriculture and forestry. To assess the role of bioenergy in light of possible negative impacts on ecosystems, the European Forest and Agricultural Sector Optimization Model (EUFASOM) assesses simultaneously economic and environmental aspects of land use. This study contributes to the assessment by analyzing the effect of bioenergy production on European wetland allocations by incorporating the spatial wetland distribution model SWEDI into EUFASOM. Results show that bioenergy targets increase land competition and thus marginal costs of wetland preservation but also of food prices. The designation of national wetland conservation targets, on the other hand, stimulates land use intensification in countries without these targets and here only a transfer of environmental stresses takes place. The model is able to illustrate regional differences of results.  相似文献   
178.
The human noroviruses (NoV) are the major cause of acute non-bacterial gastroenteritis and are commonly transmitted by foodborne routes. Epidemiological evidence from propagated outbreaks, as well as environmental sampling, suggest that these viruses are environmentally stable. The purpose of this study was to examine the persistence of representative human NoV on the fingertips of volunteers and on commonly used food preparation surfaces. Human fingerpads and surfaces (stainless steel, Formica®, and ceramic) were inoculated with 20% fecal suspensions of Norwalk virus (NV) or Snow Mountain virus (SMV). The virus inocula were recovered by elution at serial time points ranging from 0 to 120 min post-inoculation (for fingerpads) and after up to 42 days (for surfaces). The quantity of detectable viral RNA, expressed as genome equivalent particles (GEP) was evaluated using quantitative real-time RT-PCR (RT-qPCR). The amount of NV RNA on the surface decreased gradually over time, with an average reduction ranging from 1.5 to 2.9 log10 GEP after 21–28 days storage under ambient conditions. SMV showed greater environmental persistence, with a 0.4–1.2 log10 GEP reduction on all three surfaces after 42 days of ambient storage. On fingerpads, the amount of human NoV RNA declined slightly (<0.25 log10) after 15 min and remained relatively unchanged thereafter (through 120 min). These results support the epidemiological evidence that food preparation surfaces and human hands can act as vehicles for human NoV transmission long after the initial contamination event has occurred.  相似文献   
179.
Climate change is a multi-dimensional issue and in terms of adaptation numerous state and non-state actors are involved from global to national and local scales. The aim of this paper is first to analyse specific institutional networks involved in climate change predominantly at the national level in South Africa and second to determine how different stakeholders perceive their role vis-a-vis climate change adaptation. Within the South African context there is a gap in understanding and evaluating how institutional networks operate and thus the findings of this work may help inform and strengthen such relationships in the future. Results showed that few institutions fully understand the implications of adaptation and their roles and responsibilities have not yet been properly defined. Constraints relating to capacity, lack of awareness and poor information flow need to be addressed. Climate change is perceived as an important issue although problems such as poverty reduction and job creation remain national priorities. Most importantly this research has demonstrated how adaptation challenges the hierarchical manner in which government works and a more collaborative approach to climate change adaptation is needed. Adaptation needs to be mainstreamed and institutional networks need to be strengthened in order for adaptation mechanisms to be effectively implemented.
Ingrid Christine KochEmail:
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180.
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