农户宅基地流转意愿的影响因素分析——基于湖北二县市的农户调查研究

通过对湖北省二县市农户宅基地流转意愿的抽样调查，采用Logistic回归模型，分析农户宅基地流转意愿与区位条件、农户家庭属性特征及经济发展水平等的关系，找出影响农户宅基地流转意愿的主要因素。研究结果表明：目前愿意将自家宅基地进行流转的农户所占比例略高于50%。按作用程度排序，影响农户宅基地流转意愿的因素依次为非农收入占总收入的比重、距县城距离、对政策了解程度、户主年龄、户主学龄；其中，距县城距离和户主年龄的影响方向为负，其它因素的作用方向为正。从区域角度来看，经济较发达地区农户非农收入已占据主导地位，农户的流动性较强，愿意流转的农户所占比例高于社会经济欠发达地区的比例；影响农户宅基地流转意愿的因素及其作用程度也存在一定的区域差异。     

微观福利视角下的库区移民搬迁意愿调查

三峡地区社会经济的发展受到资源、环境的限制,又面临再次移民的规划.为有效的缓解由于搬迁中搬迁主体与搬迁规划向左而产生的社会矛盾,优化搬迁政策制度,实现社会的和谐,就应分析库区移民自身的福利状态与搬迁意愿之间的关系.本文在福利理论分析框架下建立理论模型并设计问卷,在多层随机抽样调查的基础上,对理论模型进行验证,运用Logit模型建立三个逐次包含的模型,进行回归分析,试图找到对移民搬迁意愿产生较大影响的福利影响因素,并分析其原因.研究表明,对于库区人口搬迁的自身福利的变化而言,最重要的影响因素为:居住环境、居住方式、教育程度、饮水方式、政策了解程度、环境满意度等;收入、承包地面积、工作等因素也起着一定的影响作用;年龄及基础设施建设中的电话和教育建设对于搬迁意愿的影响则不明显.     

三峡库区农村移民安置模式对移民家庭收入的影响分析

利用2007年三峡库区就地后靠农村移民的抽样调查数据,根据农村移民收入来源理论，采用单因素方差分析方法，对移民户和非移民户，以及不同安置方式移民户的收入结构进行比较分析，以说明移民搬迁和不同安置方式对移民收入的不同影响。结果表明：移民搬迁对移民收入存在结构性的影响，即移民搬迁主要影响移民户的家庭经营收入，同时，移民的后期扶持政策抵消了移民搬迁对移民收入的影响；不同的安置方式对移民户收入也存在显著的影响，纯农业安置和兼业安置对移民收入的不利影响较小，而非农业安置对移民户收入的影响较大；非移民安置户享受到的惠农政策和移民后期扶持政策的好处也相对要少；从收入来源的角度来讲，纯农业安置和兼业安置的收入风险相对较低，而非农业安置的收入风险相对较高，所以，纯农业安置和兼业安置对多数农村移民而言是较为适合的安置模式，移民后期扶持补助政策对于稳定移民收入有积极作用     

陕西安康移民搬迁农户的生计适应策略与适应力感知

从社会-生态系统适应性理论出发,借鉴脆弱性研究中的适应性理论来研究我国易地移民搬迁农户的适应策略和适应力,构建了移民搬迁农户的生计适应性分析框架,并以陕西安康移民搬迁工程为例,通过实地调查和访谈获取了安康搬迁农户的调查数据,分析了安康移民搬迁农户的生计适应策略、适应力感知及其影响因素。分析发现安康移民搬迁农户在搬迁之后采用了四种生计适应策略,即传统生计专业化型、非农专业化、补贴依赖型和多样化生计,这四种类型占全部搬迁农户样本的比例分别为:28.6%、34.3%、18.3%和18.8%。搬迁农户的适应力感知类型与搬迁类型、安置类型存在着统计上的显著差异。尤其是搬迁农户收入等级类型与适应力感知之间存在显著差异,越是高收入户,越表示收入增加,搬迁后"稳得住、能致富"的情况则越好;而贫困户搬迁之后的生计适应、生计安全状况令人担忧。此外,搬迁农户不同的生计适应策略与其适应力感知也存在着统计上的显著差异。总体上看,搬迁之后,非农专业化和传统生计专业化的农户收入减少的更少、表示收入增加的更多、适应力更好,而补贴依赖型、生计多样化型农户的适应状况要差一些。本文进一步采用MULTINOMINAL LOGISTICS回归模型分析了安康移民搬迁农户适应力感知的影响因素。结果显示,政府主导的移民安置方式、搬迁类型、搬迁农户所获得的扶贫项目数对搬迁农户生计适应情况并没有显著的影响,搬迁农户也没有随着搬迁时间的增加而提高其适应力;当地搬迁农户劳动力也存在一些闲置、土地林地需要进一步提高生产经营效率等。当地地方政府仍需要进一步完善移民搬迁方案和对移民搬迁农户的精准帮扶措施,发展后续产业,提高其适应力。     

三峡库区典型生态屏障区农户向外转移意愿及影响因素分析

向区外转移一定数量的过载人口是三峡生态屏障区土地生态功能建设的前提。基于农户访谈与问卷调查，对三峡库区典型生态屏障区内的涪陵、奉节、秭归、夷陵4区县的农户转移意愿进行了抽样调查，并采用Logistic回归模型对影响农户转移意愿的因素进行了分析。结果显示：613%的被调查户愿意转移，影响农户转移意愿的主要因素为户主文化水平、家庭非农收入比重、人均耕地面积、村社距集镇距离和村社环境，户主的文化水平越高、家庭非农收入比重越大、人均耕地面积越多，所处村社距集镇的距离越远、环境越差，则农户向外转移的意愿就越强烈。另外，地区因素对农户的转移意愿也存在一定影响，4个样本区县中农户转移意愿强度从大到小依次排列为秭归、涪陵、夷陵和奉节，其愿意转移的发生比率（Odds Ratio）为5047∶1637∶1166∶1。为了激励屏障区农户实行自愿转移，促进三峡后续工作规划的顺利实施，建议政府根据影响因素分析结果选择目标转移人群，并制定完善的人口转移政策以加强农户对转移后的经济收入、生产生活环境改善的预期，从而增强转移意愿     

鱼和熊掌不可兼得?易地搬迁，家庭贫困与收入分异

作为当代中国重大民生工程,易地搬迁能在多大程度上减少家庭贫困仍未成共识,后2020扶贫成效的巩固和提升有赖于瞄准相对贫困的群体,由此深化对移民社区动态和生计的理解是重要的。文章基于减少贫困和缩小差距双重视角,从微观农户层次定量考察易地搬迁的政策效应,深入剖析了导致移民接续生计分化的因素及其贡献比率。使用来自陕南的调查数据,借助反事实分析框架,模拟了移民在不搬迁情境下的收入,通过比较搬迁和不搬迁情境下移民的贫困和收入差异变化发现,搬迁一方面显著降低了家庭贫困发生率、贫困深度和强度,帮助他们跨越了"贫困陷阱",另一方面也打破了原来的低水平均衡,可能伴生移民收入分异的问题。收入差异决定因素分解结果表明:导致不同类型家庭收入分化的因素既有共性也有差异,无论对于移民还是非移民,是否为生态示范村、耕地面积、家庭规模、是否靠近车站、宗教信仰都是左右家庭收入的主要因素,与此同时,信贷可得性、可求助户数、是否为低保户对移民收入具有特殊的意义;正式和非正式的外部支持经由家庭生计选择深刻地影响着搬迁户的发展方向和层次。研究结果意味着,扶贫搬迁面临消除贫困和平衡发展两难兼顾的现实挑战,在搬迁扶贫的过程中,既要关注贫困的减少也要防范收入分异可能导致的移民社会脱节和社区撕裂风险,避免按下葫芦浮起瓢。为此,除了要保证资源再分配中的公平公正,还要注意提供正规的信贷支持和拓展移民的社会关系网络,为相关群体创造平等的发展环境。     

丹阳市宅基地使用权流转意愿的影响因素及相互作用

通过丹阳市4个村320户农户实地问卷调查，分析了丹阳市宅基地使用权流转意愿的影响因素，由Logistic回归分析模型，给出了影响因素的驱动力、贡献率的数学表达。结果表明：文化程度、宅基地个数、家庭总收入等影响因素对流转意愿呈正相关；户主年龄、家庭人口数量等影响因素对流转意愿呈负相关。同一农户的影响因素在不同阶段对流转意愿度的贡献率不同，家庭收入和户主年龄是影响宅基地流转的主要因素，他们对宅基地流转分别起着推力和阻力作用，在相互作用过程中，两者之间彼此消长。实地抽样结果分析表明，丹阳农村户主文化程度若为初中且年龄在35岁时，家庭收入能达到34 000元的话，宅基地使用权流转意愿度超过50%。以后每年家庭收入能有一定增速的话，农户流转意愿度将持续保持在50%以上。     

易地移民搬迁对农户生态系统服务依赖度的影响——来自陕南的证据

为从微观农户视角分析易地移民搬迁对生态系统服务依赖度的影响,本文构建了农户生态系统服务依赖度指数,将农户从生态系统服务中获取的各种收益进行整合和量化,利用在陕南安康地区的入户调研数据,对比分析不同搬迁类型和特征家庭的生态系统服务收益和依赖度差异,并进一步检验易地移民搬迁对农户生态系统服务依赖度的影响。结果发现:搬迁户获得的生态系统总净收益、供给、调节、文化等服务净收益以及社会经济净收益均高于非搬迁户;不同搬迁特征的农户之间的生态系统服务依赖度差异显著;易地移民搬迁工程的实施能有效的降低农户对生态系统服务的依赖程度,参与易地移民搬迁有利于农户收入结构的优化,在降低从生态系统获取供给服务的同时,也提高了社会经济收入所占比重;自愿搬迁、集中安置和新阶段的移民等特征也在降低农户对生态系统服务的依赖上起到了积极作用,自愿搬迁的农户比非自愿搬迁农户能更好的应对和适应向非资源依赖型生计模式的转变。集中安置的方式能够产生一定的规模效应和政策溢出,使农户有机会获得更多配套和后续支持,从而提高对外部机会和资源的占有能力,拓宽非资源型收入的途径,此外,新阶段易地移民搬迁工程所提供的惠民措施和补贴力度都较以往零星的自主搬迁有较大提高,同时也强调搬迁农户在非农转变过程中的自我发展能力的建设和引导。本研究为实现生态系统服务与家庭福祉在微观尺度的结合提供路径支持和方法借鉴,也为新时期易地扶贫搬迁政策的持续推进提供启示。     

基于Logit模型的非自愿性移民迁徙分析

我国每年由于建设拆迁、水库工程等引发的移民迁徒数量比较大,移民搬迁涉及政治、经济、社会、民族、宗教、文化等诸多方面,是一项复杂的系统工程.为了更好地为中央对三峡库区移民可持续发展规划提供政策建议,笔者在三峡库区内选择有代表性的W县进行实地调研,调查涉及3个镇、19个村、46个组、9061户,在对调查数据进行Logit分析后得到如下结论:在不考虑搬迁补偿金额和帮扶政策等外部选择条件的前提下,如果只考虑移民自身的特征与其拥有的环境资源禀赋数据会发现:农户自身家庭收入、土地面积以及居住环境、居住位置、居住方式等因素会对农户的搬迁意愿产生显著的影响.因此我们建议在库区搬迁规划时在一定条件下应根据农户的实际条件进行有选择性的搬迁,而不是一刀切式的政策,这样可以避免在实施搬迁过程中的造成的社会冲突与矛盾.     

不同类型农户对宅基地退出的响应

利用重庆市梁平县农户的调查数据,运用Logistic模型,探讨了户籍制度改革下不同类型农户宅基地退出意愿及其影响因素。结果表明：(1)在现有退地补偿政策下农户意愿普遍偏低,不同类型农户退地意愿存在一定的差异性;(2)影响纯农户宅基地退出的因素有户主年龄、家庭拥有的房屋数量、对政策的支持度和退地收益;影响Ⅰ兼业户宅基地退出的因素有家庭宅基地面积大小、对政策的支持度和退地收益;影响Ⅱ兼业户宅基地退出的因素有家庭小孩数、对政策的支持度和退地收益;影响非农户宅基地退出的因素有户主年龄、户主文化程度、家庭人口数、宅基地面积和退地收益;其中,退地收益是影响各类农户退地决策最显著的因素,对政策的支持度是农户退地决策影响力最大的因素。研究认为,影响各类农户退地决策的因素存在差异,其核心问题还在于退地政策。政府应根据不同类型农户的特征完善目前的农村宅基地退出政策,这有助于提高农户的参与意愿,顺利推进户籍制度和农村土地制度的改革     

How to assess exposure of aquatic organisms to manufactured nanoparticles?

Ecological risk of chemicals is measured by the quotient of predicted no-effect concentrations and predicted exposure concentrations, which are hard to assess for manufactured nanomaterials (NMs). This paper proposes modifications to currently used models, in order to make them suitable for estimating exposure concentrations of NMs in the aquatic environment. We have evaluated the adequacy of the current guidance documents for use with NMs and conclude that nano-specific fate processes, such as sedimentation and dissolution need to be incorporated. We have reviewed the literature on sedimentation and dissolution of NMs in environmentally relevant systems. We deduce that the overall kinetics of water-sediment transport of NMs should be close to first order. The lack of data on dissolution of NMs under environmentally realistic conditions calls for a pragmatic decision on which rates to be used in modeling. We find that first order removal kinetics for dissolution seems adequate. Based on limited data from literature, probable removal rates range from 0 to 10(-4)s(-1) for sedimentation, and from 0 to 10(-5)s(-1) for dissolution. Further experimental data at environmentally relevant conditions for sedimentation and dissolution of NMs is needed.     

Using fuzzy set theory to address the uncertainty of susceptibility to drought

This paper presents the technical aspects of a new methodology for assessing the susceptibility of society to drought. The methodology consists of a combination of inference modelling and fuzzy logic applications. Four steps are followed: (1) model input variables are selected—these variables reflect the main factors influencing susceptibility in a social group, population or region, (2) fuzzification—the uncertainties of the input variables are made explicit by representing them as ‘fuzzy membership functions’, (3) inference modelling—the input variables are used to construct a model made up of linguistic rules, and (4) defuzzification—results from the model in linguistic form are translated into numerical form, also through the use of fuzzy membership functions. The disadvantages and advantages of this methodology became apparent when it was applied to the assessment of susceptibility from three disciplinary perspectives: Disadvantages include the difficulty in validating results and the subjectivity involved with specifying fuzzy membership functions and the rules of the inference model. Advantages of the methodology are its transparency, because all model assumptions have to be made explicit in the form of inference rules; its flexibility, in that informal and expert knowledge can be incorporated through ‘fuzzy membership functions’ and through the rules in the inference model; and its versatility, since numerical data can be converted to linguistic statements and vice versa through the procedures of ‘fuzzification’ and ‘defuzzification’.     

Using GRADE to respond to health questions with different levels of urgency

Increasing interest exists in applying the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to environmental health evidence. While ideally applied to evidence synthesized in systematic reviews and corresponding summary tables, such as evidence profiles, GRADE's correct application requires that “the evidence that was assessed and the methods that were used to identify and appraise that evidence should be clearly described.” In this article, we suggest that GRADE could be applied to evidence assembled from narrative reviews, modelled (indirect) evidence, or evidence assembled as part of a rapid response, if the underlying judgments about the certainty in this evidence are based on the relevant GRADE domains and provided transparently. Health questions that require assessing the certainty in a body of evidence to provide trustworthy answers may range from hours, to days or weeks, to a few months to scenarios that allow assessing evidence without short-term time pressures. Time frames of emergent, urgent or rapid evidence assessments will often require relying on existing summaries or rapidly compiling the available evidence and making assessments. Even without available full systematic reviews, expressing the certainty in the evidence can provide useful guidance for users of the evidence and those who evaluate certainty in effects. The ratings also help clarifying disagreement between organizations tackling similar questions about the evidence. Using the structured GRADE domains, narrative or other summaries of the evidence can be presented transparently.     

Resilience of stocking capacity to changing climate in arid to Mediterranean landscapes

Small livestock is an important resource for rural human populations in dry climates. How strongly will climate change affect the capacity of the rangeland? We used hierarchical modelling to scale quantitatively the growth of shrubs and annual plants, the main food of sheep and goats, to the landscape extent in the eastern Mediterranean region. Without grazing, productivity increased in a sigmoid way with mean annual precipitation. Grazing reduced productivity more strongly the drier the landscape. At a point just under the stocking capacity of the vegetation, productivity declined precipitously with more intense grazing due to a lack of seed production of annuals. We repeated simulations with precipitation patterns projected by two contrasting IPCC scenarios. Compared to results based on historic patterns, productivity and stocking capacity did not differ in most cases. Thus, grazing intensity remains the stronger impact on landscape productivity in this dry region even in the future.     

A gender approach to understanding the differentiated impact of barriers to adaptation: responses to climate change in rural Ethiopia

While adaptation has received a fair amount of attention in the climate change debate, barriers to adaptation are the focus of a more specific, recent discussion. In this discussion, such barriers are generally treated as having a uniform, negative impact on all actors. However, we argue that the precise nature and impact of such barriers on different actors has so far been largely overlooked. Our study of two drought-prone communities in rural Ethiopia sets out to examine how female- and male-headed households adapt to climate change, particularly focusing on how a variety of barriers influence the choice of adaptation measures to varying extents. To this purpose, we built a conceptual framework based on the Sustainable Livelihood Approach. Data were collected using semi-structured interviews and focus group discussions with male- and female-headed households, community leaders and local extension workers. Our findings suggest that gender-based differences in the choice of adaptation measures at the household level are driven by cultural, social, financial and institutional barriers. Barriers to adaptation—particularly when interacting—have a differentiated impact upon different actors. This outcome hints at the need for donors and policymakers to develop intervention strategies that are sensitive to this fact.     

Morphological and biological features of plants related to their adaptation to coastal habitats

The results of studies on the biomorphological features of 22 plant species growing on the southern coast of the Russian Far East provide evidence for the diversity of pathways of their adaptation to stressful habitat conditions. An analysis of the anatomical and mesostructural characteristics of their leaves has revealed representatives of euhalophytes, crinohalophytes, and glycohalophytes among these plants. Adaptation is achieved by means of halomorphosis, haloxerophytism, and development of some heliophilic features accounted for by species-specific manifestations of succulence, the presence of salt excreting trichomes, and thick pubescence. The similarity of these adaptations to those of desert plants is discussed. Along with plants characterized by a high germination rate, species that counterbalance a low efficiency of seed reproduction by active vegetative propagation have also successfully established themselves on the coast. Adaptation to coastal habitats is also achieved due to the diversity of life forms characterized mainly by tap root systems with laterally extending branch roots, creeping shoots, and a high vegetative mobility.     

Modelling the propagation of effects of chronic exposure to ionising radiation from individuals to populations

This study evaluated the potential effect of ionising radiation on population growth using simple population models and parameter values derived from chronic exposure experiments in two invertebrate species with contrasting life-history strategies. In the earthworm Eisenia fetida, models predicted increasing delay in population growth with increasing gamma dose rate (up to 0.6 generation times at 11 mGy h(-1)). Population extinction was predicted at 43 mGy h(-1). In the microcrustacean Daphnia magna, models predicted increasing delay in population growth with increasing alpha dose rate (up to 0.8 generation times at 15.0 mGy h(-1)), only after two successive generations were exposed. The study examined population effects of changes in different individual endpoints (including survival, number of offspring produced and time to first reproduction). Models showed that the two species did not respond equally to equivalent levels of change, the fast growing daphnids being more susceptible to reduction in fecundity or delay in reproduction than the slow growing earthworms. This suggested that susceptibility of a population to ionising radiation cannot be considered independent of the species' life history.     

Approaches to Quantitative Assessment of Biological Damage to Forest Communities under Technogenic Load

General trends in simplification of the structure and composition of forest communities in the zone of impact from the metallurgical industry are revealed. The load of toxicants is estimated from the concentrations of heavy metals in the snow and soil. The method is proposed for assessing biological damage on the basis of the main characteristics of phytocenosis, such as its species diversity and the cenotic significance of its structural components. The resultant integrated index of phytocenosis preservation (IIP _p) characterizes the degree of biological damage, and its value depends on the load of toxicants and resistance of plant communities characteristic of different natural zones.     

Application of fuzzy models to assess susceptibility to droughts from a socio-economic perspective

By combining the concepts of environmental stress, state susceptibility and environmental crisis, “Security Diagram” (SD) provides a quantitative approach to assessing environmental change and human security. The SD is a tool that clearly presents in a diagram the security situation of a population or region affected by a particular environmental crisis. Its underlying concept emphasises that the higher the level of environmental stress and socio-economic susceptibility, the higher the probability of the occurrence of crisis. Focusing on drought, this study analyses the susceptibility of case study regions in India, Portugal, and Russia from a socio-economic perspective. A conceptual framework of socio-economic susceptibility is developed based on the economic development theories of modernisation and dependency. Fuzzy set theory is used to generate susceptibility indices from a range of national and sub-national indicators, including financial resources, agricultural dependency and infrastructure development (for economic susceptibility), and health condition, educational attainment and gender inequality (for social susceptibility). Results indicate that socio-economic susceptibility over the period 1980–1995 was highest in India, followed by Russia and (since 1989) lowest in Portugal. Globalisation is likely to contribute to changes in the level of socio-economic susceptibility over time. Moreover, specific social and economic structures unique in each country (e.g., the role of women in society in India, the socialist legacy in Russia) may explain differences in susceptibility between the case study regions.