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31.
乐安河-鄱阳湖湿地植物群落分布及其环境影响因子   总被引:6,自引:0,他引:6       下载免费PDF全文
于2012年平水期(4月)、丰水期(8月)和枯水期(11月)对乐安河自上游至下游及入鄱阳湖区域内湿地植物群落分布和水土环境因子进行调查,分析乐安河不同水期湿地植物群落的分布特征,通过DCCA(detrended canonical correspondence analysis,除趋势典范对应分析)探讨不同水期植物群落分布特征与环境因子间的定量关系. 结果表明:3个水期内共观测到湿地植物167种,不同水期植物种类及组成结构均具有显著差异. 其中平水期湿地植物102种,分属于33科75属;枯水期71种,分属于27科53属;丰水期种类最少,为55种,分属于20科42属. 乐安河上游处于未受矿山开采影响的对照区域内,水生植物群落分布主要受河流自然环境因素的影响. 对于受重金属酸性污染影响较严重的区域,DCCA排序结果显示,水土环境中pH和Cu、Pb、Cd等重金属含量是影响植物群落分布的重要因素. 其中,上游湿地植物群落分布主要受Cu含量和pH的影响;中、下游主要受水、土环境中重金属Pb、Cd的复合污染以及pH的影响. 乐安河湿地植物群落分布与环境因子间具有明显的对应关系,DCCA法能准确识别影响湿地植物群落分布的关键环境因子.   相似文献   
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This paper addresses two important issues for large Mediterranean city regions: the differential impact of compact urban ‘growth’ and low-density ‘sprawl’ on land cover changes (LCCs), and their final effect on changing land cover relationships (LCRs). The urban expansion of Rome (Italy) during the last 50 years and the related LCCs were investigated as a paradigmatic example of compact versus dispersed urban development. LCCs were assessed over 5 years (1960, 1974, 1990, 2000, 2006) by analysing diachronically the distribution of 12 land cover categories derived from digital land cover maps covering the entire Nuts-3 prefecture of Rome (5353 km2). LCRs were studied using multi-way data analysis. LCCs were found to have relative differences during ‘growth’ (1960–1990) and ‘sprawl’ (1990–2006) phases. Conversion to urban land uses concentrated in the 1960s and 1970s at the urban fringe, while expanding progressively far from the city in the 1990s and 2000s. During the ‘growth’ phase, the land cover classes with the highest probability of being converted to urban uses were arable lands, annual crops, vineyards and pastures. During the ‘sprawl’ phase, olive groves, orchards and forest surfaces also decreased due to the development of low-density built-up areas and infrastructure. Planning suggestions aimed at mitigating the alteration of the rural landscape through sprawl conditions are discussed.  相似文献   
34.
Sociological and anthropological studies in India reveal that caste, class and gender in everyday life are both rigid and dynamic, but little is known about how they influence the survival mechanisms of women during ‘multiple disasters’, nor about how women negotiate with these structural mores to meet their cultural and biological needs. This is explored through the experiences of 12 women-headed households from different social castes in Orissa, India. Multiple disasters or disasters that occur in ‘one specific place’ (such as floods, cyclone and drought) are regular events in coastal parts of the state of Orissa. The super-cyclone of 1999, two floods of 2001 and 2003 and drought of 2000 and 2002 form the case study. Participant observation, in-depth interviews and documentary evidence complement the fieldwork. The findings suggest a complex interplay of caste, class and gender in surviving the multiple disasters including structural mutability under the purview of social organization. In doing so, women demonstrated their individual and collective agencies in order to meet their cultural and biological needs under severe crisis. This research stresses that gender and disaster studies must include a consideration of caste and class for effective disaster management and social vulnerability reduction.  相似文献   
35.
Aim. Firefighters must meet minimum physical demands. The Norwegian Labour Inspection Authority (NLIA) has approved a standardised treadmill walking test and 3 simple strength tests for smoke divers. The results of the Trondheim test were compared with those of the NLIA tests taking into account possible effects of age, experience level and gender. Methods. Four groups of participants took part in the tests: 19 young experienced firefighters, 24 senior male firefighters and inexperienced applicants, 12 male and 8 female. Results. Oxygen uptake (VO2) at exhaustion rose linearly by the duration of the treadmill test. Time spent on the Trondheim test was closely related to performance time and peak VO2 on the treadmill test. Senior experienced firefighters did not perform better than equally fit young applicants. However, female applicants performed poorer on the Trondheim test than on the treadmill test. Performance on the Trondheim test was not closely related to muscle strength beyond a minimum. Conclusion. Firefighters completing the Trondheim test in under 19 min fit the requirements of the NLIA treadmill test. The Trondheim test can be used as an alternative to the NLIA tests for testing aerobic fitness but not for muscular strength. Women’s result of the Trondheim test were poorer than the results of the NLIA treadmill test, probably because of their lower body mass.  相似文献   
36.
ABSTRACT

Women’s experiences of drought are often made invisible particularly in terms of their long-term effects. Drought differs from other “natural disasters” in that droughts are, by definition, experienced over an extended time. This means those experiencing drought do so as they age, with elderly cohorts particularly vulnerable. As such, there is a need to better understand the longitudinal needs and experiences of women living with drought. This study investigates the experiences of drought for 15 Australian women aged over 70, over a period of 12 years. Longitudinal qualitative free-text comments written by the oldest cohort of women in the Australian Longitudinal Study on Women’s Health were subject to a thematic analysis. Findings indicate that experiences of drought have a relationship to women’s ability to age in ways they may have hoped. Themes of Work and Physical activity, Connection to place, and, Service access were prominent in women’s comments. These results demonstrate that place is an important aspect in the experience of ageing, that work and physical activity often intensify during drought for elderly people who might otherwise be expecting to retire, and that drought presents particular challenges for older women in terms of access to services. This study highlights the complex interactions of living and ageing in drought for Australian women.  相似文献   
37.
The geologic and geomorphic expressions of a mineral deposit determine its location, size, and accessibility, characteristics which in turn greatly influence the success of artisans mining the deposit. Despite this critical information, which can be garnered through studying the surficial physical expression of a deposit, the geologic and geomorphic sciences have been largely overlooked in artisanal mining‐related research. This study demonstrates that a correlation exists between the roles of female miners at artisanal diamond and gold mining sites in western and central Africa and the physical expression of the deposits. Typically, women perform ore processing and ancillary roles at mine sites. On occasion, however, women participate in the extraction process itself. Women were found to participate in the extraction of ore only when a deposit had a thin overburden layer, thus rendering the mineralized ore more accessible. When deposits required a significant degree of manual labour to access the ore due to thick overburden layers, women were typically relegated to other roles. The identification of this link encourages the establishment of an alternative research avenue in which the physical and social sciences merge to better inform policymakers, so that the most appropriate artisanal mining assistance programs can be developed and implemented.  相似文献   
38.
Nest site selection and induced response in a dominant arboreal ant species   总被引:1,自引:1,他引:0  
It is well known that arboreal ants, both territorially dominant species and plant ants (e.g., species associated with myrmecophytes or plants housing them in hollow structures), protect their host trees from defoliators. Nevertheless, the presence of an induced defense, suggested by the fact that the workers discovering a leaf wound recruit nestmates, is only known for plant ants. Based on the results from a field study, we show here (1) that colonies of Azteca chartifex, a territorially dominant, neotropical arboreal ant species, mostly selected Goupia glabra (Goupiaceae) trees in which to build their principal carton nests and (2) that plant signals induced workers to recruit nestmates, which patrol the leaves, likely providing the plant with a biotic defense. Furthermore, the number of recruited workers was clearly higher on G. glabra, their most frequently selected host tree species, than on other tree species. These results show that contrary to what was previously believed, induced responses are also found in territorially dominant arboreal ants and so are not limited to the specific associations between myrmecophytes and plant ants.  相似文献   
39.
Deployment in a crisis zone is a perilous undertaking. Little is known right now about how humanitarian workers relate social and professional goals to lived experiences of high-risk environments. In South Sudan, ranked as the most dangerous country globally for aid workers, 20 international humanitarian staff were interviewed to examine their sense of place, well-being, and vocation, using thematic and interpretative phenomenological analysis. Subjectivities of humanitarian space hinged upon negotiating physical hardships and social relationships: Juba, the capital, was described as a ‘prison’ and a ‘party hotspot’. For expatriate staff, making sense of spatial, social, and professional transience was sharply gendered and rooted in the subjectivities of risk-taking, crisis management, and career-building. Two policy measures are highlighted here to address the implications of transience for human well-being and organisational effectiveness. Efforts to support teams and structure work environments, altering the humanitarian and vocational bubble, will help to develop resilience at the heart of humanitarian systems.  相似文献   
40.
A central question in the study of predator–prey relationships is to what extent prey behaviour is determined by avoidance of predators. Here, we test whether the long-term risk of encountering lions and the presence of lions in the vicinity influence the behaviour of large African herbivores at waterholes through avoidance of high-risk areas, increases in group size, changes in temporal niche or changes in the time spent in waterhole areas. In Hwange National Park, Zimbabwe, we monitored waterholes to study the behaviour of nine herbivore species under different risks of encountering lions. We radio-collared 26 lions in the study area which provided the opportunity to monitor whether lions were present during observation sessions and to map longer-term seasonal landscapes of risk of encountering lions. Our results show that the preferred prey species for lions (buffalo, kudu and giraffe) avoided risky waterholes. Group size increased as encounter risk increased for only two species (wildebeest and zebra), but this effect was not strong. Interestingly, buffalo avoided the hours of the day which are dangerous when the long-term and short-term risks of encountering lions were high, and all species showed avoidance of waterhole use at night times when lions were in the vicinity. This illustrates well how prey can make temporal adjustments to avoid dangerous periods coinciding with predator hunting. Additionally, many herbivores spent more time accessing water to drink when the long- and short-term risks of encountering lions were high, and they showed longer potential drinking time when the long-term risk of encountering lions was high, suggesting higher levels of vigilance. This study illustrates the diversity of behavioural adjustments to the risk of encountering a predator and how prey respond differently to temporal variations in this risk.  相似文献   
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