Invasive plants – friends or foes? Contribution of prickly pear (Opuntia ficus-indica) to livelihoods in Makana Municipality,Eastern Cape,South Africa

The negative impacts of invasive alien species on the environment are well documented. However, despite the predominantly negative perceptions associated with invasive species, it is evident that a number of these plants have been part of the landscape for generations and have numerous commercial and non-market uses. Consequently, there is a need for research that considers the impact of invasive species on the livelihoods and well-being of local communities. The authors investigated the contribution that the trade in prickly pear (Opuntia ficus-indica), an invasive alien species, makes to the household income streams of poor trading households. The research highlights the apparent conflict of interests and trade-offs that exists between local traders, for whom the sale of the prickly pear provides a livelihood source, and the South African Government, who are actively seeking to remove the plant from the landscape.     

浅析高速公路岩石边坡喷混植生技术的特点和技术关键

文中对高速公路岩石边坡喷混植生技术进行了较全面的综合总结,主要涉及到喷混植生技术的概念、特点、技术关键及应用。     

REGULATION AND THE NATURAL PROGRESS OF OPULENCE

Adam Smith taught us how government regulation can counteract the market forces that produce economic growth. Here I explore a more complex interplay between regulation and economic growth. Regulation creates behavioural incentives that weaken or offset entirely the goal of the regulation. Growth produces many of the benefits ascribed to regulation while also hiding the costs and failures of regulation.     

Does Question Format Matter? Valuing an Endangered Species

A three-way treatment design is used to compare contingent valuation response formats. Respondents are asked to value an endangered species (the red-cockaded woodpecker) and the restoration of its habitat following a natural disaster. For three question formats (open-ended, payment card, and double-bounded dichotomous choice), differences in survey response rates, item non-response rates, and protest bids are examined. Bootstrap techniques are used to compare means across formats and to explore differences in willingness to pay (WTP) distribution functions. Convergent validity is found in a comparison of mean WTP values, although some differences are apparent in the cumulative distribution functions. Differences across formats are also identified in item non-response rates and proportion of protest bids. Overall, the payment card format exhibits desirable properties relative to the other two formats.     

Effects of competitive interactions of different life forms submersed plants on biomass allocation in shallow lakes

Plant competition has been recognized as one of the most important factors influencing the soructure and function of lake ecosystems. Competition from plants of dissimilar growth form may have profound effects on shallow lakes＇. An experiment was conducted to investigate the effects of competitive interactions of submersed plants with dis- similar growth forms on the biomass allocations. Hydrilla verticitlata and Vallisneria natans were selected and were planted in a single-species monoculture and a mixed-species pattern, Results showed that the growth of E natans was＇ significantly affected by the tt, verticillata and caused a sharp reduction of biomass, but the root：shoot ratio of E ha- tans was not affected significantly and there was a minimal increase in mixture： while for H. verticillata, the biomass and the root：shoot ratio were not significantly changed by the competitive interactions ore natans, there was minimal increase of biomass and minimal decrease of the root：shoot ratio. These results may indicate that theplant which can develop a dense mat or canopy at the water surface would be a stronger competitor relative to the plant that depends more on light availability near the sediment.     

新兴速生树种推广优势、经济效益及发展对策研究——以速生竹柳为例

介绍了竹柳的来源与特性;从可有效缓解国内森林资源稀缺现状、可有效缓解国内木材供给压力、可增加森林碳汇储量而有效应对气候变暖、有利于保护生态环境并丰富生物多样性、有利于推动种养结合而缓解畜禽养殖业环境污染5个方面分析了竹柳推广造林的优势;实证分析了竹柳育苗的经济效益、预测分析了竹柳成材林栽植的经济效益。结果表明:竹柳具有栽植密度高、生长速度快、抗性强、成活率高和用途广泛的特点;经营竹柳育苗和成材林每年可分别实现利润148.18和101.12万元/hm2。建议广泛组织科研单位对竹柳进行科研论证;加强市场治理,规范竹柳经营;加大政策支持力度,引导社会资本参与竹柳经营;结合竹柳特性,打造竹柳生态产业链;做好长期规划,推动竹柳林纸一体化经营。     

Drivers and projections of vegetation loss in the Pantanal and surrounding ecosystems

Modeling scenarios can help identify drivers of and potential changes in land use, particularly in rapidly changing landscapes such as the tropics. One of the places where most of the recent anthropogenic land use changes have been occurring is the "arc of deforestation" of the Amazon, where several scenarios have been constructed. Such modeling scenarios, however, have been implemented less frequently in wetland areas, but these are also undergoing rapid change. An example is the Pantanal, one of the largest wetlands on the planet located in the Upper Paraguay River Basin (UPRB). The UPRB is formed by the lowland (Pantanal) and the plateau (Cerrado and Amazon where the spring-fed rivers are). We used a spatially explicit model to identify drivers of vegetation loss in the Pantanal and surrounding area (UPRB) and estimated potential vegetation loss for the next 30 years. The model is probabilistic and considers that vegetation loss is contagious, so that the local rate of deforestation increases over time if adjacent sites are deforested, also taking into account the drivers identified in those locations. Our study is the first to simulate vegetation loss at property-scale, over 20,000 properties, for the entire UPRB in Brazil, taking into account the relationship between the plateau, where headwaters are located, and the lowland, where flooded-areas are concentrated. The drivers of vegetation loss identified for the lowland (distance to roads and rivers and elevation) differed from those for the plateau (distance to cities), demonstrating the relevance of analyzing areas separately. The cumulative rate of native vegetation loss projected for 2050 was 3% for the lowland and 10% for the plateau, representing losses of 6045 km² and of native vegetation area decreasing from 87% to 83% and 7960 km² from 39% to 35% respectively by 2050, if changes continue at the same pace and if the environmental legislation is followed. The projected vegetation loss in the UPRB forms a geographical arc, very similar to that observed in the Amazon, from the plateau into the lowland. The arc is directly related to areas with no or low flooding frequency because they are suitable for agriculture. The identification of this arc of vegetation loss calls for urgent conservation policies for this wetland and new perspectives for management.     

弗洛姆类伦理思想之主旨与马克思人学思想的渊源

弗洛姆类伦理思想与马克思的人学思想有着密切的关系。马克思关于人性、本质及其能动性,以及社会主义目标等理论对弗洛姆产生了很大的影响。由此,弗洛姆从人性出发,奠定了其类伦理思想始基,认为人的生存是一种社会性的存在。他把生产性作为人解决生存矛盾、实现潜能的动力机制。弗洛姆类伦理思想的普遍价值标准是人的幸福,而幸福是生产性活动的结果,也是生产性活动的激励;幸福是美德的标准,是生产性的充分发展。     

Shark hunting: On the vulnerability of resources with heterogeneous species

This paper examines the unprecedented decimation of sharks. In accordance with the biological characteristics and the economic environment of sharks, we extend the Brander-Taylor model of renewable resources and trade to a resource with a continuum of species which are heterogeneous with respect to their growth rate. The model implies that heterogeneity increases the vulnerability of a resource as relatively abundant species make harvesting economically viable even though slow-growing species are driven to extinction. The empirical analysis assesses the fate of sharks in the light of the model and finds that the likelihood of extinction is, indeed, significantly greater for shark species which exhibit low intrinsic growth.     

植物景观在校园中的营造——以黑垦农职院为例

介绍了黑龙江农垦农业职业技术学院这一特殊地理位置的气候特点、目前在植物配置方面存在的问题,提出了校园内植物景观塑造的要点及改善办法。