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1.
Dynamics and Causation of Environmental Equity, Locally Unwanted Land Uses, and Neighborhood Changes
Feng Liu 《Environmental management》1997,21(5):643-656
/ Why are some environmental risks distributed disproportionately in the neighborhoods of the minorities and the poor? A hypothesis was proposed in a recent study that market dynamics contributed to the current environmental inequity. That is, locally unwanted land uses (LULUs) make the host communities home to more poor people and people of color. This hypothesis was allegedly supported by a Houston case study, whereby its author analyzed the postsiting changes of the socioeconomic characteristics of the neighborhoods surrounding solid waste facilities. I argue that such an analysis of postsiting changes alone is insufficient to test the causation hypothesis. Instead, I propose a conceptual framework for analysis of environmental equity dynamics and causation. I suggest that the presiting neighborhood dynamics and the characteristics of control neighborhoods be analyzed as the first test for the causation hypothesis. Furthermore, I present theories of neighborhood change and then examine alternative hypotheses that these theories offer for explaining neighborhood changes and for the roles of LULUs in neighborhood changes. These alternative hypotheses should be examined when analyzing the relationship between LULUs and neighborhood changes in a metropolitan area. Using this framework of analysis, I revisited the Houston case. First, I found no evidence that provided support for the hypothesis that the presence of LULUs made the neighborhoods home to more blacks and poor people, contrary to the conclusion made by the previous study. Second, I examined alternative hypotheses for explaining neighborhood changes-invasion-succession, other push forces, and neighborhood life-cycle; the former two might offer better explanation.KEY WORDS: Environmental equity and justice; Locally unwanted lane uses; Siting; Market dynamics; Invasion-succession; Neighborhood changes 相似文献
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Forest resources play a key role and provide many basic needs to communities in developing economies. To assess the patterns of vegetation cover change, as a corollary of resource utilization, satellite imagery, ground truth data, and image processing techniques can be useful. This article is concerned with identifying change in major vegetation types in East Timor between 1989 and 1999, using Landsat Thematic Mapper data. The results highlight a significant level of deforestation and decline in foliage cover. All major vegetation cover types declined from 1989 to 1999, and there was a sizeable increase in degraded woodlands. This decline has had considerable impact on the livelihoods of rural and urban communities. Causes for these changes include: economic exploitation of abundant resources; and implications of transmigration policies implemented during Indonesian rule, resulting in increased competition for land and woodland resources. As the new nation of Timor‐Leste establishes itself, it must consider its current stock and distribution of natural capital to ensure that development efforts are geared towards sustainable outcomes. Without the knowledge of historical patterns of resource consumption, development efforts may, unwittingly, lead to continuing decline in forest resources. 相似文献
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基于福建三明499户农户的实地调查数据,用倾向得分匹配法测算了生态公益林现金直接补偿和岗位性补偿对农户的增收效应,结果表明:现金直接补偿和岗位性补偿对生态保护和农户增收都是正效应。现金直接补偿对农户增收效应不显著,而岗位性补偿对农户家庭总收入和家庭人均收入的净效应分别达55.4%和57%。进一步研究发现,两种补偿方式对贫困户和非贫困户的增收效应也不尽相同,其中现金直接补偿不利于贫困户增收,而岗位性补偿对不同收入的农户都具有正向显著增收效应。此外,从生态公益林的根本使命出发,可以发现现金直接补偿和岗位性补偿对生态保护的净效应也存在较大差异。故此,科学规划生态补偿方式和补偿标准是实现生态保护和农户增收双重效应的根源所在。 相似文献
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森林资源资产存量变化核算是建立森林资源资产管理绩效考核制度、遏制森林资源资产流失的必要前提与基础。在基于3S技术构建区域森林资源资产存量变化核算方案的基础上,对2000—2010年北京市森林资源资产存量数量、质量及其变化展开核算与分析。结果显示:在数量方面,除落叶阔叶林减少以外,其余各类森林数量都有不同程度增加,其中平谷区、顺义区果园林与海淀区、朝阳区城市绿地森林以及密云县、延庆县、门头沟区的落叶阔叶灌木林增幅最为显著;在质量方面,森林资源资产综合质量差、中2种等级森林面积都呈小幅减少趋势,质优森林面积大幅增加,其中平谷区、密云县增加最为显著;总体而言,2000—2010年间北京市森林资源资产存量数量大面积增加、森林质量大幅度提高,总体呈累积增加态势。 相似文献
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本文研究了湖南省中亚热带次生林的种群动态,建立了静态生命表、存活曲线、结构模型以及材积或生物量动态模型,提出了中亚热带次生林的演替基本模式。 相似文献
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Numerous analyses of the possible impacts of future climatic changes on tree species composition have been published for
both lowland and high-elevation forests. Most of these studies were based on the application of forest "gap" models, and the
vast majority of them considered only changes in the average of climatic parameters over time. In this study, we use a unique
data set on reconstructed past climatic variations to analyse forest dynamics simulated by the forest gap model ForClim. This
analysis forms the basis for a systematic exploration of the ecological effects of changing means vs. changing variability
of climate on central European forests. A reconstruction of historical climate covering the last 470 years in the Swiss lowlands
(ClimIndex) is extrapolated to a transect across the alpine (cold) treeline and used to simulate the influence of climate
variations on the time scale of decades on forest biomass and tree species composition at both sites. While the simulation
at the low-elevation site shows little sensitivity to climate variations, the results from upper subalpine forests suggest
that two major dieback events would have occurred at elevations above the current but below the climatic tree line, induced
by clusters of exceptionally cold summers. The results are in agreement with available dendrochronological data and with documentary
evidence on massive negative impacts on flora and fauna at high elevations during these periods. We conclude that ForClim
is capable of capturing the effects on tree population dynamics of climate variability at these sites as reconstructed from
the ClimIndex record. A factorial design is used to address the sensitivity of ForClim to changes of the long-term averages
vs. changes of the variability of monthly temperature and precipitation data. To this end, the simulated tree species composition
of near-natural forests is examined along a climate gradient in Europe. The results indicate that there are three types of
forest response: (1) little sensitivity to both kinds of change, (2) strong sensitivity to changes in the means, but little
sensitivity to changing variability, and (3) strong sensitivity to changing variability at least in parts of the examined
climate space. Half of the cases investigated fall under the third category, suggesting that emphasis should be placed on
also assessing the sensitivity of ecosystems to future changes in climate variability rather than on changes of average values
alone.
Electronic Publication 相似文献
10.
The data on the dynamics of population size and species composition of wasps from the families Pompilidae, Sphecidae, and Vespidae were obtained in the course of long-term studies carried out in successional pine forests of the Berezinskii Biosphere Reserve. The abundance and species diversity of wasps were significantly higher in a polewood forest (40 years) than in a young forest (20 years) and mature moss forest (70 years). In an overgrown ride in the moss pine forest, the composition of dominant wasp species remained relatively stable during the seven-year period of observations, although the number of species and their abundance varied significantly from year to year, depending on the weather. 相似文献