Managing invasive alien species with professional and hobby farmers: Insights from ecological-economic modelling

Biosecurity is a great challenge to policy-makers globally. Biosecurity policies aim to either prevent invasions before they occur or to eradicate and/or effectively manage the invasive species and diseases once an invasion has occurred. Such policies have traditionally been directed towards professional producers in natural resource based sectors, including agriculture. Given the wide scope of issues threatened by invasive species and diseases, it is important to account for several types of stakeholders that are involved. We investigate the problem of an invasive insect pest feeding on an agricultural crop with heterogeneous producers: profit-oriented professional farmers and utility-oriented hobby farmers. We start from an ecological-economic model conceptually similar to the one developed by Eiswerth and Johnson [Eiswerth, M.E. and Johnson, W.S., 2002. Managing nonindigenous invasive species: insights from dynamic analysis. Environmental and Resource Economics 23, 319-342.] and extend it in three ways. First, we make explicit the relationship between the invaded state carrying capacity and farmers' planting decisions. Second, we add another producer type into the framework and hence account for the existence of both professional and hobby farmers. Third, we provide a theoretical contribution by discussing two alternative types of equilibria. We also apply the model to an empirical case to extract a number of stylised facts and in particular to assess: a) under which circumstances the invasion is likely to be not controllable; and b) how extending control policies to hobby farmers could affect both types of producers.     

WFGD系统对汞的影响分析

利用现有控制技术来协同控制汞污染是一项科学、合理、经济的技术措施。目前普遍认为脱硫系统对脱汞有着较大去除潜力，但脱硫系统对脱汞的影响大小及影响特性有着较大的不确定性，分析了脱硫系统各运行因素对汞的影响特性及汞的二次污染等问题，为科学合理的制定汞排放技术提供参考。     

我国药用植物资源利用的研究

通过近年来我国药用植物资源研究现状的综述，分析其存在的主要问题，同时提出合理开发利用的技术手段和措施，并指出重视药用植物资源可持续发展的必要性。     

对于火力发电厂燃料系统安全运行的探究分析

输煤系统是火力发电厂里重要的标志性组成部分,而输煤皮带的安全运行最为直接的影响了电厂的安全指标和经济效益。本文从火力发电厂燃料运行系统安全运行方面,对其影响因素进行分析探究,并提出防范对策,让今后在有效维护和保证系统安全运行时有所参考。     

Bush v. Gore and the Effect of New Source Review on Power Plant Emissions

New Source Review (NSR) is a Clean Air Act regulation that requires electric utilities to meet emission standards when making modifications to existing power plants. The regulation increases the cost of replacing worn out parts, and limits the firm’s scope of potential capital investments. Such restrictions may lead to greater retirements and lower utilization, adversely affecting profits. Prior to the 2000 presidential election, investors expected Bush to have a narrower interpretation of NSR than Gore. Therefore, we use changes in stock prices to estimate the effect on profits of differences in NSR policy. Our results indicate that investors expected the average boiler to be $38 million more valuable under the Bush administration. Over the boilers’ lifetimes, the additional utilization will have increased emissions by 19 million tons of sulfur dioxide, 5.9 million tons of nitrogen oxides and 980 million tons of carbon dioxide, relative to natural gas generation.      

Analysis of the Colorado potato beetle protection system in Finland

Invasive species, including plants, insects and other pests, are a serious threat to agricultural production and to the environment in general. Finland has traditionally had a favourable situation concerning invasives, partly due to its isolated geographical location. The situation may now be changing and one of the currently increasing threats is the Colorado potato beetle (CPB). Finland has designed a CPB protection policy incorporating a protected zone, which is commonly used to deal with invasive plant pests in other European countries. Within this zone, the randomly occurring CPB invasions are collectively fended off, to prevent the establishment of a permanent pest population and to minimise potential damage. This paper evaluates the economics of the current protection programme, comparing this to a hypothetical situation in which the current pre-emptive policy is abandoned and control relies on producers' individual reactive protection measures. The annual random pest invasions are modelled in a static stochastic framework. To date the pest has not been able to establish a permanent population in Finland. According to our analysis, the currently exercised pre-emptive policy is the cost-efficient choice at this point. The relatively low expected invasion magnitude is one of the key factors supporting the efficiency of the current system. Another reason is the fairly small damage incurred. However, when the invasions become larger and more frequent or the pest strains more cold-resistant, the future situation may change.     

Trade and invasive species risk mitigation: Reconciling WTO compliance with maximising the gains from trade

This paper analyses the issue of balancing the gains from trade with the risk of pest and disease transference. Two decision frameworks for determining whether or not to permit trade in a potentially invasive species-carrying good are presented. The first considers only the potential production losses resulting from an invasive species entering through a trade pathway, as is prescribed by WTO compliance. The second is a unilateral welfare-maximising approach which considers the consumer gains from trade, the loss of domestic producers’ market share and expected damage from the invasive species. It is shown that these alternative decision frameworks can be reconciled such that they produce the same outcome regarding whether or not trade is to be permitted. The key parameters which influence these decisions are also highlighted.     

沉陷废弃地复垦新途径探讨

研究目的:目前沉陷地复垦的主要形式是以充填覆土为主,但矿区内覆土来源的缺乏严重影响复垦的进行,该研究拟寻求沉陷废弃地复垦的新途径.研究方法:试验分析法.研究结果:粉煤灰与糠醛渣以4:1质量比混配的新型复垦材料,符合部分牧草、草坪、花卉及棉花等植物生长的肥力标准和质量标准.研究结论:该复垦材料为沉陷地的生态修复提供了新的理论和途径,而且实现以废治废,节土造田,降低了成本28.9%.对提高沉陷地的复垦速度,促进经济、社会及生态环境的持续健康发展具有重要的作用.     

井冈山的珍稀濒危植物及其保护与利用

井冈山分布着国家保护的珍稀濒危植物39种,省级保护59种,井冈山特有分布种10种。这些珍稀濒危植物在医药、花卉、化工原料、木材等方面具有较高的开发利用价值。由于近年来井冈山林区的城市化建设以及人口增加过快等因素的影响,致使许多珍贵稀有植物濒临灭绝,森林生态系统遭到严重破坏。因此,积极保护与合理利用这些资源迫在眉睫。     

Relationships between absenteeism,conservation group membership,and land management among family forest owners

Absentee landowners, or those who do not live on their forestland, own approximately 117 million acres of private forestland in the U.S. Thus, their land management decisions and activities influence the flow of forest-based goods and services. We explore the question of whether absentee family forest owners are less active land managers than resident landowners and whether membership in conservation organizations is associated with higher levels of land management activity by absentee owners. To examine these questions, we administered a mail survey to randomly-selected family forest landowners in Indiana. While we found some support for the contention that absentee owners are less active forestland managers than resident owners, we also found they are not necessarily inactive landowners. We found absentee owners were less likely to have: inspected their forestland for invasive plants, pulled or cut invasive plants, used herbicides to kill invasive plants, reduced fire hazard, or grazed livestock than resident owners. Absentee owners were more likely to be enrolled in the Indiana Classified Forest and Wildlands Program, a preferential forest property tax program. Absentee owners who are members of a conservation organization were more likely than absentee non-member owners to have undertaken a variety of land management activities, including: undertaking wildlife habitat improvement projects, inspecting their forestland for invasive plants, pulling or cutting invasive plants, enrolling in the Indiana Classified Forest and Wildlands program, and obtaining a management plan.