A Political Economy in an Ecological Web

Behavior matters more to environmental policy than most people think. This paper illustrates why this point needs repeating in four ongoing policy debates in the United States – Children's health risk, ozone/particulate matter (PM), climate change, and endangered species.     

基于遥感数据的郑州市植被覆盖度变化研究

植被覆盖度是衡量某一地区植被覆盖状况的指标,某一地区的植被覆盖状况会直接影响到该地区的土壤、水分和气候等自然环境要素。随着中原经济区的快速发展,郑州市作为中原经济区的增长极,发展速度很快,城市扩张迅速。为了研究郑州市的快速发展给生态环境带来的影响,选取植被覆盖度这一指标为研究对象,利用不同时间阶段的遥感影像估算郑州市不同时期的植被覆盖度,通过分析植被覆盖度变化来研究郑州市的快速增长对植被覆盖度造成的影响。结论如下:(1)2000年郑州市的植被覆盖度主要以低植被覆盖为主,2014年以中低植被覆盖度为主,高植被和较高植被覆盖度略有提高;(2)从植被覆盖度变化来看,2000—2014年整个研究区植被覆盖度主要以轻微增加为主。     

土壤种子库在生态园林工程中的应用潜力 研究

土壤种子库作为自然生态系统的基因库,是传统生 态修复的主要手段之一,但在生态园林建设中并未引起足够 的重视。以广东省深圳市为例,选取梧桐山自然保护区2种 具有代表性的群落类型(常绿阔叶混交林和荔枝纯林),研究 了土壤种子库的萌发特征,以及覆盖物(椰糠和园林废弃物) 对常绿阔叶混交林土壤种子库演替初期群落生长的影响。结 果表明：1)2种林型土壤种子库物种丰富度相当,分别为常 绿阔叶混交林9种、荔枝纯林8种,荔枝纯林土壤种子库密度 和覆盖率分别为576.29粒/m2 、15.31%,明显高于常绿阔 叶混交林236.93粒/m2 、7.57%;2)覆盖物能显著提升常 绿阔叶混交林土壤种子库种子萌发的数量及早期演替群落的 覆盖度,具体表现为：椰糠组(密度：648.58粒/m2 、覆盖 率：13.74%)＞园林废弃物组(密度：368.56粒/m2 、覆盖 率：11.11%)＞对照组(密度：236.93粒/m2 、覆盖率： 7.57%);3)2种林型土壤种子库与地上植被的物种相似度均 很低,分别为常绿阔叶混交林0.16,荔枝纯林0.19。结果表 明,从土壤种子库的物种丰富度、密度和早期演替群落盖度来 看,梧桐山土壤种子库在生态园林工程中的应用潜力很大,可 以作为深圳乃至华南地区生态园林建设的重要手段。同时,在 实际工程应用中,可以运用椰糠等覆盖物促进种子的萌发及演 替早期群落的形成。     

内蒙古西部生态建设与植物种选择

从内蒙古西部地区生态环境恶化严重制约着区域经济发展的实际出发,介绍了生态环境恶化的严重性以及生态建设中应该高度重视优良植物品种选择的重要性,并在对植物种选择进行了长期的试验研究,并汇总和分析的基础上,提出了植物种选择的建议。     

Big Economic History

This paper reviews the history of human economic activity from the time Homo sapiens appeared to the present. The first aim is to provide a coherent narrative of the economic history of this period. The second aim is to quantify economic activities where time series data is available and to use economic theory to explain the trends and turning points. It examines the history of three central time series – the aggregate human population, output per capita and human‐induced species extinctions. It concludes with some brief observations on the contribution of Big Economic History to Big Human History.     

A Relational Theory of Risk: a Case Study of the Asian Longhorned Beetle Infestation in Worcester,MA

Abstract

The rise of globalization and global increases in temperature have prompted the spread of invasive species, which poses a major threat to the ecosystem benefits provided by urban forests. Stakeholders such as urban residents, policy-makers, and forestry industry professionals deem these risks differently because they place value on threatened goods and services at different spatial and temporal scales. This article will use the frameworks of relational risk theory and relational place-making to connect ‘risk objects’ and ‘objects at risk’ to better understand how relationships of risk shape responses to threats to the environment. The data in this study comes from Worcester, MA, where discovery of the Asian Longhorned Beetle prompted the United States Department of Agriculture to remove 35,000 trees from streets and backyards in the quarantine zone. The three different stakeholder groups that were targeted for data collection were green industry representatives, government decision makers, and residents. Green industry representatives, decision makers, and residents were interviewed while additional residents responded to a survey. The results showed that greater understanding of the different objects and places at risk removed misconceptions between different stakeholders. Understanding is increased when each stakeholder recognizes the different spatial scales of the objects at risk. This improvement of transparency can lead to better communication of the variety of risks posed by invasive species and a faster and more unified response to the threats from invasive species or other natural disasters.     

旅游干扰对峨眉山风景区土壤及植被的影响

文章利用室外调查与室内分析相结合的方法,分析了旅游干扰对峨眉山景区内的植被与土壤性质的影响。试验结果表明:旅游干扰对峨眉山景区中的植被影响比较明显,植被均匀度指数、丰富度指数、优势度指数以及多样性指数都低于对照区,其中草本层所受到的影响最为严重,达到显著水平(P0.05)。在干扰活动下,草本层的均匀度指数、丰富度指数、优势度指数及多样性指数分别比对照降低了13.42%、29.81%、10.12%及17.69%。此外,旅游干扰也对景区土壤性质造成较大影响,干扰使土壤容重进一步增加,同时降低了土壤有机质、全氮、全钾及速效养分的含量,在对不同土层深度分析中表明,干扰区土壤各理化性状随着土层深度的增加而增加,而对照区土壤各理化性状随着土层深度的增加而减少,旅游干扰对土壤理化性质影响显著。     

Public Preferences and Willingness to Pay for Forest Disease Control in the UK

Invasive pests and diseases in trees impose a range of costs on society related to reductions in timber values, impacts on recreational opportunities and effects on forest biodiversity. These costs need to be considered when assessing control options and developing public policy. We investigate the preferences and willingness to pay of the UK general public for a range of forest disease control measures using a choice experiment with a sample of 605 people. Respondents were relatively well informed about general tree disease‐related issues, such as causes and general measures to minimise the risk of disease spread. They were less knowledgeable about specific tree diseases, with Dutch elm disease and chalara ash dieback being the most well known. We find that disease control programmes in publicly‐owned forests and forests owned by charitable trusts are more likely to be supported by the public than equivalent control programmes in privately‐owned and/or commercial forests. The nature of scientific uncertainty about diseases does not affect peoples’ preferences for disease control measures significantly. Higher respondent income, greater ex‐ante knowledge about tree diseases, and more frequent visits to forests are correlated with greater willingness to support publicly‐funded tree disease control programmes in forests. Better knowledge about tree diseases also improves the clarity of respondents’ choices. We find a negative sentiment against some disease control measures, such as clear felling of a forest, and chemical or biocide spraying. We conclude that there is significant public support for part‐financing forest disease control policies in the UK, but that this is conditional on forest ownership and the type of control measures used.     

Invasive species: The categorization of wildlife in science,policy, and wildlife management

Species categories commonly used in nature conservation, such as protected, endangered, reintroduced, or invasive, are open to various interpretations that can result in diverging and sometimes serious consequences. This is vividly apparent with respect to invasiveness because the categorization of species and individual animals as invasive impacts on how they are treated in practice. This article demonstrates how different constructions of invasiveness in science, policy, and wildlife management can be traced back to different assessments of the origin, behavior, and impact of the invasives. Specifically, the focus is on the different conceptions of space and the role of data in the categorization of invasives. We find that, in science and policy, invasiveness is constructed mainly in terms of the origin and impact of invasives but that these domains differ in how they treat space in their assessment of origin: whereas science uses ecological spaces, such as biogeographical regions, to assess whether a species belongs to, or is invasive in, a certain area, policy uses policy spaces such as countries or states to do so. In assessing the impact of invasives, science argues about including it in its definition, whereas policy requires detailed data about ecological, societal, and economic damage in order to take action. In wildlife management, the focus in the construction of invasiveness shifts from origin and impact to behavior of invasives. This requires detailed data about where the invasives are, where they are going, and what they are doing. By showing the dynamic and context-specific nature of the construction of invasiveness, the article contributes to ongoing research about classifications of nature, their difficulties and ambiguities, and their implementation and consequences in practice.     

昆明市部分行道绿化树种经营效益成本分析与评价

在阐明STRATUM模型的研究思路及研究方法的基础上,选用该模型中与昆明市区相近气候区相应树种综合效益计算的参数数据,采用典型抽样调查对昆明市区悬铃木等16个主要行道树树种群体的经营管理效益成本之比进行了计算和比较分析研究,并针对这些主要行道树树种的选择应用及其经营管理现状加以评价,从而提出优化方案和完善建议。