美国对外农业投资格局演变及其影响因素——兼论“一带一路”农业合作

对外农业投资是“一带一路”倡议的重要内容,研究美国对外农业投资特征,既可总结先行之国的发展经验,也可响应并适应主要竞争对手的投资行为,为充分利用两个市场、两种资源提供科学依据。本文立足对外直接投资理论,采用Logistic模型与面板数据分析方法,研究了2000-2018年美国对外农业投资的时空格局、影响因素及其对“一带一路”农业合作的启示。结果表明:（1）美国对外农业投资以食品加工等产前产后环节为主,主要分布于西欧等发达国家以及墨西哥、巴西等地理临近的发展中国家。（2）美国对外农业投资呈现显著的市场导向特征,同时也受到地理与文化距离、国家治理等东道国因素的影响。（3）对比中美对外农业投资特征,结合当前国际经贸形势与中国农业国际合作目标,建议中国进一步优化农业产业链布局,在促进实现联合国可持续发展目标的同时,提高中国在全球粮安领域的定价权与渠道把控力;进一步深耕既有对外农业投资市场,在降低地缘竞争压力的同时,充分挖掘潜在市场机会;关注“一带一路”沿线国家的农业技术需求,保证投资目标与东道国的投资需求相协调;尤需解决中国对外农业投资面临的文化与体制差异较大等现实问题,提高“一带一路”农业合作项目的可持续性。     

长江经济带农业源非二氧化碳温室气体排放的时空特征

利用清单方法核算了1980~2016年长江经济带农业源非二氧化碳（CO₂）温室气体的排放总量和排放强度,分析了不同经济发展情景和农业-环境脱钩状态下长江经济带2030年和2050年的排放情景.研究表明：时间维度上,1980~2016年长江经济带农业源非CO₂温室气体排放总量呈上升趋势,从0.26Gt CO₂-eq上升到0.32Gt CO₂-eq;2030年和2050年在高情景和中情景2种情景下,长江经济带农业源非CO₂温室气体排放量不会达峰,江苏、湖南、重庆、云南、湖北和安徽等六省（市）的单位农地面积排放强度将增加;3种情景下,四川始终为单位农地面积排放强度较低的地区.     

华东地区公众低碳意识及其影响因素分析研究

基于安吉县、临安市、杭州市和上海市4个地区公众低碳意识的调研数据,对不同性别、不同年龄、不同学历、不同月收入水平和不同居住地公众的低碳意识(低碳认知、低碳消费、低碳践行、低碳责任)进行了单因素方差分析,在此基础上,利用广义线性模型(GLM)对影响公众低碳意识的因素进行了实证分析.分析结果表明,公众的学历和居住地对公众低碳意识有显著的影响.基于分析结果,最后提出增强公众低碳意识、促进社会低碳发展的建议.     

基于低碳发展的企业资源损失定量分析及其应用

低碳经济是企业发展中面临的选择,但目前的研究却缺少企业产品生产过程中的资源消耗与环境影响问题之间的定量分析.另有研究发现,企业处于积极环境行为的第一个层次,即只要企业污染治理水平停留在企业污染治理边际成本和企业污染治理边际收益相等处,企业治理环境就是可以获得收益的,因而,企业有进行降低环境影响的强烈需求.本文运用物质流成本会计(MFCA),从数量与价值角度使企业资源损失定量化,使其损失结构清晰化,因此有利于企业找到损失改善点,促使企业减少资源的初始投入量、提高资源使用率,并降低环境影响.以一个案例进行具体运用,在此基础上,引入外部损害成本原理,通过"资源流内部损失-废弃物外部损害"双重维度分析,使企业资源损失从经济性和环境性方面得到全面体现.本文从微观层面为企业低碳经济发展提供了一个新的研究视角.     

Effects of Oil‐Palm Plantations on Diversity of Tropical Anurans

Agriculturally altered vegetation, especially oil‐palm plantations, is rapidly increasing in Southeast Asia. Low species diversity is associated with this commodity, but data on anuran diversity in oil‐palm plantations are lacking. We investigated how anuran biological diversity differs between forest and oil‐palm plantation, and whether observed differences in biological diversity of these areas is linked to specific environmental factors. We hypothesized that biological diversity is lower in plantations and that plantations support a larger proportion of disturbance‐tolerant species than forest. We compared species richness, abundance, and community composition between plantation and forest areas and between site types within plantation and forest (forest stream vs. plantation stream, forest riparian vs. plantation riparian, forest terrestrial vs. plantation terrestrial). Not all measures of biological diversity differed between oil‐palm plantations and secondary forest sites. Anuran community composition, however, differed greatly between forest and plantation, and communities of anurans in plantations contained species that prosper in disturbed areas. Although plantations supported large numbers of breeding anurans, we concluded the community consisted of common species that were of little conservation concern (commonly found species include Fejervarya limnocharis, Microhyla heymonsi, and Hylarana erythrea). We believe that with a number of management interventions, oil‐palm plantations can provide habitat for species that dwell in secondary forests. Efectos de las Plantaciones de Palma de Aceite sobre la Diversidad de Anuros Tropicales Faruk et al.     

Effects of Pond Draining on Biodiversity and Water Quality of Farm Ponds

Farm ponds have high conservation value because they contribute significantly to regional biodiversity and ecosystem services. In Japan pond draining is a traditional management method that is widely believed to improve water quality and eradicate invasive fish. In addition, fishing by means of pond draining has significant cultural value for local people, serving as a social event. However, there is a widespread belief that pond draining reduces freshwater biodiversity through the extirpation of aquatic animals, but scientific evaluation of the effectiveness of pond draining is lacking. We conducted a large‐scale field study to evaluate the effects of pond draining on invasive animal control, water quality, and aquatic biodiversity relative to different pond‐management practices, pond physicochemistry, and surrounding land use. The results of boosted regression‐tree models and analyses of similarity showed that pond draining had little effect on invasive fish control, water quality, or aquatic biodiversity. Draining even facilitated the colonization of farm ponds by invasive red swamp crayfish (Procambarus clarkii), which in turn may have detrimental effects on the biodiversity and water quality of farm ponds. Our results highlight the need for reconsidering current pond management and developing management plans with respect to multifunctionality of such ponds. Efectos del Drenado de Estanques sobre la Biodiversidad y la Calidad del Agua en Estanques de Cultivo     

Effects of cyanobacteria producing microcystins on seed germination and seedling growth of several agricultural plants

The effects of cyanobacteria aqueous extracts containing Microcystin-LR (MC-LR) on the seed germination and growth of Pisum sativum, Lens esculenta, Zea mays and Triticum durum were investigated. Experiments were carried out on a range of doses of the extract (equivalent to 0, 1.6, 2.9, 5.8, 8.7 and 11.6 μ g MC-LR/mL). The results confirm that these plants were sensitive to cell-free extracts of a toxic Microcystis and that germination inhibition was dose dependent. One-way analysis of variance (ANOVA) showed that P. sativum is the most sensitive tested species with a 97% germination rate reduction and L. esculenta was the most resistant. At the 8th day, the exposure to the microcystins (MC) resulted in a significant decrease of plant epicotyls length, roots length and a net inhibition of lateral root formation. It is concluded that MC could affect also terrestrial plants seedling germination and growth. Therefore, the use of water for irrigation contaminated by MC could exert negative biochemical effects on seed and plant metabolism which might influence the agricultural crops.     

Impacts of tropical forest disturbance on species vital rates

Tropical forests are experiencing enormous threats from deforestation and habitat degradation. Much knowledge of the impacts of these land-use changes on tropical species comes from studies examining patterns of richness and abundance. Demographic vital rates (survival, reproduction, and movement) can also be affected by land-use change in a way that increases species vulnerability to extirpation, but in many cases these impacts may not be manifested in short-term changes in abundance or species richness. We conducted a literature review to assess current knowledge and research effort concerning how land-use change affects species vital rates in tropical forest vertebrates. We found a general paucity of empirical research on demography across taxa and regions, with some biases toward mammals and birds and land-use transitions, including fragmentation and agriculture. There is also considerable between-species variation in demographic responses to land-use change, which could reflect trait-based differences in species sensitivity, complex context dependencies (e.g., between-region variation), or inconsistency in methods used in studies. Efforts to improve understanding of anthropogenic impacts on species demography are underway, but there is a need for increased research effort to fill knowledge gaps in understudied tropical regions and taxa. The lack of information on demographic impacts of anthropogenic disturbance makes it difficult to draw definite conclusions about the magnitude of threats to tropical ecosystems under anthropogenic pressures. Thus, determining conservation priorities and improving conservation effectiveness remains a challenge.     

Cultivating food as a right to the city

This paper argues that there is much to be gained when we view struggles to cultivate food in the city through the lens of Henri Lefebvre's concept of the right to the city. Lefebvre's idea helps us better perceive the radical political and ecological potential of those struggles. And in the empirical details of the struggles we can see concretely the key action in Lefebvre's concept, an action that is only abstract in his work: urban inhabitants becoming active and producing and managing space for themselves.     

Food production in the city: (re)negotiating land,food and property

This paper addresses issues of access to land for food production in Toronto by offering fresh perspectives on urban agriculture in the neo-liberal city of the global north. It examines attempts to scale up urban agriculture that emphasise changing the relationships between land access, property and new collaborative relationships among different stakeholders. These initiatives involve renegotiating access to land for growing food between private property owners and landless growers, concomitant shifts in control over valued resources and commercialisation. These shifts are often based on relations of trust within a sharing economy rather than public battles over political decisions to develop urban agriculture lands. Growing food on private lands in the city is political in challenging taken-for-granted ideas and practices of property and urban agriculture. New approaches offer options for training and income, as well as expanding the land base for urban agriculture. Small-scale farming projects are affirmative political manoeuvres. They challenge urban residents to consider land for food production across the categories of public and private property. We document three approaches that challenge current property relations: temporary use of a development site through “soft” squatting; redesignating suburban backyards for farmer training and community-based and private food production; and garden sharing of private home backyards for urban food production and commercial growing. Such initiatives articulate alternative visions of sustainability and food security that rely on principles of collaboration and a sharing economy that challenge prevailing notions of property ownership and food security.