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51.
Climate change is challenging conservation strategies for protected areas. To summarise current guidance, we systematically compiled recommendations from reviews of scientific literature (74 reviews fitting inclusion criteria) about how to adapt conservation strategies in the face of climate change. We focussed on strategies for designation and management of protected areas in terrestrial landscapes, in boreal and temperate regions. Most recommendations belonged to one of five dominating categories: (i) Ensure sufficient connectivity; (ii) Protect climate refugia; (iii) Protect a few large rather than many small areas; (iv) Protect areas predicted to become important for biodiversity in the future; and (v) Complement permanently protected areas with temporary protection. The uncertainties and risks caused by climate change imply that additional conservation efforts are necessary to reach conservation goals. To protect biodiversity in the future, traditional biodiversity conservation strategies should be combined with strategies purposely developed in response to a warming climate.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-022-01779-z.  相似文献   
52.
Tracer tests provide highly valuable information about the transport properties of saturated rocks which is essential to the characterization of a potential radioactive waste repository site. In the frame of El Berrocal project, a set of tracer tests was performed in a complex geometry of inclined boreholes, combined with highly fractured transmissive zones. The aims of the tracer test programme were to gain experience, knowledge and insight into field transport experiments. To achieve this a detailed programme of new instrumentation design, site characterization and laboratory tasks was developed. For field monitoring a new electronic system was developed. The system is able to measure up to 256 parameters per borehole, with surface equipment to control pumping rates and physical and chemical parameters at both injection and extraction boreholes. The experiments progressed from single borehole dilution tests under both natural flow and forced gradient conditions to convergent flow tracer tests. Dilution tests helped to discriminate the most suitable borehole sections at which to inject tracers. The tracers were selected by the results of the laboratory programme. Uranine (fluorescein), DTPA-gadolinium (diethylenetriaminopentacetic acid, gadolinium (III)), and deuterium were injected simultaneously in one borehole section and recovered at another borehole 20 m away, pumping at a flowrate of 0.1 1 min−1. First results showed a thickness porosity of 1.2 × 10−3 m and a longitudinal dispersivity of 17.0 m using uranine data acquired over a period of 4 d, at which point the recovery concentration had reached a maximum. However, gadolinium and deuterium appeared to travel faster, arriving at peak values after only 2 d of injection.  相似文献   
53.
棉铃虫暴发的特点,成因及治理对策   总被引:12,自引:0,他引:12  
戴小枫  郭予元 《灾害学》1994,9(1):22-30
本文就1992年我国棉铃虫暴发成灾的特点与成因进行了详细的分析,并讨论了治理这一灾害性农业害虫的策略与方法。  相似文献   
54.
Migration of 137Cs and 90Sr in undisturbed soil was studied in large lysimeters three and four years after contamination, as part of a larger European project studying radionuclide soil–plant interactions. The lysimeters were installed in greenhouses with climate control and contaminated with radionuclides in an aerosol mixture, simulating fallout from a nuclear accident. The soil types studied were loam, silt loam, sandy loam and loamy sand. The soils were sampled to 30–40 cm depth in 1997 and 1998. The total deposition of 137Cs ranged from 24 to 45 MBq/m2, and of 90Sr from 23 to 52 MBq/m2. It was shown that migration of 137Cs was fastest in sandy loam, and of 90Sr fastest in sandy loam and loam. The slowest migration of both nuclides was found in loamy sand. Retention within the upper 5 cm was 60% for both 137Cs and 90Sr in sandy loam, while in loamy sand it was 97 and 96%, respectively. In 1998, migration rates, calculated as radionuclide weighted median depth (migration centre) divided by time since deposition were 1.1 cm/year for both 137Cs and 90Sr in sandy loam, 0.8 and 1.0 cm/year, respectively, in loam, 0.6 and 0.8 cm/year in silt loam, and 0.4 and 0.6 cm/year for 137Cs and 90Sr, respectively, in loamy sand. A distinction is made between short-term migration, caused by events soon after deposition and less affected by soil type, and long-term migration, more affected by e.g. soil texture. Three to four years after deposition, effects of short-term migration is still dominant in the studied soils.  相似文献   
55.
采用一维土柱下渗实验和垂向入渗模型相结合的方式,研究垃圾渗滤液中邻苯二甲酸二乙基己基酯(DEHP)和邻苯二甲酸二正丁酯(DBP)在土壤中的垂向迁移演化规律。结果表明:原状土和混有石英砂土的土柱对DBP的吸附能力均强于DEHP,而混有石英砂的土柱中DEHP、DBP均出现不同程度的穿透现象,且DEHP的穿透速度比DBP要快2倍;做或不做防渗处理,DEHP和DBP渗出量均呈前期快速增长而后期归于稳定的趋势,防渗对DBP效果较DEHP好;垂向入渗模型与一维土柱实验结果一致,该模型可用于其他区域有机污染物在土壤中垂向迁移的研究。  相似文献   
56.
水库区是水库水面与周边陆地的区域复合体。本文以山东大中型水库区为例,在调查研究的基础上,探讨了库区贫困的根源及库区脱贫的出路,并提出了库区发展的战略构想。  相似文献   
57.
Marine protected areas (MPAs) have become a key component of conservation and fisheries management to alleviate anthropogenic pressures. For MPA networks to efficiently promote persistence and recovery of populations, ecological connectivity, i.e. dispersal and movement of organisms and material across ecosystems, needs to be taken into account. To improve the ecological coherence of MPA networks, there is hence a need to evaluate the connectivity of species spreading through active migration and passive dispersal. We reviewed knowledge on ecological connectivity in the Baltic Sea, Kattegat and Skagerrak in the northeast Atlantic and present available information on species-specific dispersal and migration distances. Studies on genetic connectivity are summarised and discussed in relation to dispersal-based analyses. Threats to ecological connectivity, limiting dispersal of populations and lowering the resilience to environmental change, were examined. Additionally, a review of studies evaluating the ecological coherence of MPA networks in the Baltic Sea, Kattegat and Skagerrak was performed, and suggestions for future evaluations to meet management needs are presented.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01684-x.  相似文献   
58.
The transport in macroporous clayey till of bromide and 25 organic compounds typical of creosote was studied using a large intact soil column. The organic compounds represented the following groups: polycyclic aromatic hydrocarbons (PAHs), phenolic compounds, monoaromatic hydrocarbons (BTEXs), and heterocyclic compounds containing oxygen, nitrogen or sulphur in the aromatic ring structure (NSO-compounds). The clayey till column (0.5 m in height and 0.5 m in diameter) was obtained from a depth of 1–1.5 m at an experimental site located on the island of Funen, Denmark. Sodium azide was added to the influent water of the column to prevent biodegradation of the studied organic compounds. For the first 24 days of the experiment, the flow rate was 219 ml day−1 corresponding to an infiltration rate of 0.0011 m day−1. At this flow rate, the effluent concentrations of bromide and the organic compounds increased very slowly. The transport of bromide and the organic compounds were successfully increased by increasing the flow rate to 1353 ml day−1 corresponding to 0.0069 m day−1. The experiment showed that the transport of low-molecular-weight organic compounds was not retarded relative to bromide. The high-molecular-weight organic compounds were retarded significantly. The influence of sorption on the transport of the organic compounds through the column was evaluated based on the observed breakthrough curves. The observed order in the column experiment was, with increasing retardation, the following: benzene=pyrrole=toluene=o-xylene=p-xylene=ethylbenzene=phenol=benzothiophene=benzofuran<naphthalene<1-methylpyrrole<1-methylnaphthalene=indole=o-cresol=quinoline<3,5-dimethylphenol=2,4-dimethylphenol<acridine<carbazole<2-methylquinoline<fluorene<dibenzofuran<phenanthrene=dibenzothiophene. This order could not be predicted from regularly characteristics as octanol/water-distribution coefficients of the organic compounds but only from experimentally determined data. The results indicate that a thin clayey till cover of the type described in this paper does not protect groundwater against contamination by low-molecular-weight organic compounds.  相似文献   
59.
To achieve 8% growth of the Indian economy, the industrial sector must grow at 10% rate. The vision statements of various core sectors of the country show that the mining sector will have to expand greatly. India is among the top ten mineral producing nations in the world and the Indian mining industry indicates almost the full range of extractive mineral products. Small-scale mining is quite prevalent in India. Such mines constitute about 90% of total number of mines, 42% of the total non-fuel minerals and metals, 5% of the fuel minerals. Some 3,000 small-scale mines account for a work force of about 0.5 million people. Yet this sector is a neglected sector in Indian economy and still considered as an unorganized sector. This article examines the community and state interests in small-scale mining and the contribution of small-scale mines to employment, national mineral production, practices, and Indian policy on small-scale mining. It identifies drawbacks in the existing Government policy and discusses a possible role for the Government to upgrade the sector. This paper highlights the impacts of mining on women community, the socioeconomic characteristics of women as miners and on the productive roles that women play in mining. It also discusses how the pursuit of sustainable livelihoods, poverty alleviation, indigenous peoples right and gender equity in artesianal and small-scale mining be more effective when these communities are disadvantaged or neglected by government policies. The respective roles of the indigenous people and migrant workers in the social organization of ASM sectors in different parts of the country are discussed. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
60.
Birds migrating along coastlines may be at increased risk if displacement occurs toward open-ocean. Eastern North America experiences prevailing northwesterly winds during autumn, which could compel some migrants to drift eastward. Therefore, migrants at stop-over sites along this route may be a mixture of on- and off-course individuals. We assessed whether orientation behavior of juvenile yellow-rumped warblers (Dendroica coronata) captured at a stop-over site in southern Nova Scotia was related to where they originated from (i.e., likely on/off-course). We hypothesized three scenarios after displacement: 1) continued orientation in the migratory direction selected before displacement, 2) orientation from the new location toward the previous destination, or 3) correction to regain the original pathway. Using stable isotopes, we determined that stop-over migrants originated from nearby areas (and assumed on-course) and as far away as western Hudson Bay, over 1,600 km northwest (and assumed off-course) of the site. We used video-based orientation registration cages to determine an individuals’ migratory orientation. Because numerous factors influence migratory orientation (e.g., fuel reserves, celestial cues), we simultaneously assessed the influence of body condition and cloud cover, in addition to geographic origin, on orientation behavior. Individuals that originated closer to the site tended to orient more southwesterly. Orientation directions became increasingly more west-northwesterly the further away an individual originated from the site (i.e., the more likely it was to have been displaced). The result is most consistent with scenario three: individuals from northwest origins likely respond to easterly displacement by orienting westerly to reestablish their previous migratory route.  相似文献   
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