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101.
Decentralization in access to and control of Bolivia's forest resources, coupled with a rising global demand for tropical hardwoods, raises important questions about whether increased trade and community forest management (CFM) initiatives can enable forms of market integration that have more favourable outcomes for rural communities. This paper assesses the prospects for such a transition through an examination of the relationships linking wood product market intermediaries (brokers and buyers) to rural suppliers and forest communities in Bolivia. The analysis centres on whether trust – conceptualized as a power‐laden sociospatial process driven by multiscalar factors – can evolve between buyers and suppliers such that more progressive (sustainable and mutually beneficial) partnerships devolop. Focusing on three types of buyer–supplier relationships in Bolivia – direct ties between wood brokers/buyers and suppliers, nongovernmental organization (NGO) mediated exchange relationships and Forest Stewardship Council (FSC) certification of suppliers – our findings show how trust building initiatives that focus on one scale may fail if factors at other scales create obstacles to collaboration, Given these relational constraints, CFM strategies in Bolivia currently face limitation on their viability as economic development strategies.  相似文献   
102.
Despite a growing trend of migration to countries in the global South fueled by their natural amenities (i.e., natural amenity migration), research on this topic has predominantly been conducted in the global North. This is problematic given the notable socioeconomic, attitudinal, and behavioral differences between amenity migrants (often urbanites from developed countries) and local people (often rural residents of developing countries). Grounded in community field theory, this study begins to fill this gap in the literature by increasing our understanding of the ways in which local residents and amenity migrants interact in the amenity-rich community of Nuevo Arenal, Costa Rica. We found that linguistic, cultural, and spatial barriers (real and perceived) created a social climate in which the interaction between local residents and amenity migrants was primarily based on mundane interactions and did not lead to social integration. This proved to be a hindrance to the creation of the community field, which led to a lack of joint planning and participation in activities and projects that sought to improve the overall living conditions in the community. Explanations of these findings and the implications of such a divide are offered.  相似文献   
103.
A two-year study was conducted in the vicinity of a harbour in sub-tropical Hong Kong, to examine the progress of improvement in sediment quality and recovery of macrobenthic community upon cessation of organic pollution caused by sewage discharge. Median sediment particle diameter (Mdphi) and levels of total organic carbon (TOC), total Kjeldahl nitrogen (TKN), ammonia-nitrogen (NH(3)-N) and total phosphorus (TP), as well as macrobenthic species composition and abundance were determined bi-monthly at three inside-harbour and two outside-harbour locations. At the two inside-harbour locations, significantly higher levels of TOC, TKN, NH(3)-N and TP in sediments were observed than the outside-harbour locations. However, no significant temporal change of nutrient levels was detected at all sampling locations during the two-year study, except a significant decrease in TKN and NH(3)-N levels at one outside-harbour location and a decline in NH(3)-N content at another outside-harbour location. Spatially, the highest in mean total species number, individual number, species diversity H' and lowest evenness J was found at one outside-harbour location, whereas the other four locations had relatively similar values. H' was negatively correlated with TOC, TKN, NH(3)-N and TP content in sediments while J was positively correlated with MDphi. Across the study period, the patterns of macrobenthic community were significantly different among all samplings and that the spatial difference of benthic community was best correlated with MDphi, TOC, TKN and water depth. A weak sign of recovery in macrobenthic community structure was detected at inside-harbour locations, with replacement of opportunistic by ubiquitous species over the two-year study. The slow recovery of macrobenthic community was related to sediment characteristics. Results of a larval settlement bioassay using the polychaete Capitella sp. I also demonstrated that the inside-harbour sediments were still unfavourable for colonization and larval settlement of species sensitive to pollution. The slow biodegradation of the organic pollutants and continuous presence of heavy metals in the sediment may hinder settlement and colonization of benthic animals. However, increases of H' and J were observed in a longer time scale when comparing the present data with those obtained four years ago. This suggested that a detectable recovery of benthic community in the harbour may take at least three years and a complete recovery may even take longer duration.  相似文献   
104.
An assessment of the effects of the 'Prestige' oil spill on intertidal, macroalgal assemblages was carried out comparing abundance data obtained before and after the spill. Four zones in the North and Northwest coast of Spain were sampled, one of them located at the immediate vicinity of the spill, the zone most heavily oiled. Macroalgal assemblages had similar structure between years. Neither critical decrease in abundance of the dominant macroalgae, nor increase in opportunistic species were found. Some differences in abundance were observed, but they did not show any pattern, being more likely the result of the natural variability of the assemblage. Extensive, but not intense fuel deposition on the shores and a limited use of aggressive cleanup methods are suggested as possible causes for the lack of the effects in these assemblages after the 'Prestige' oil spill.  相似文献   
105.
Human activities are exposing freshwater ecosystems to a wide range of stressors, whose direct and indirect effects can be alleviated or exacerbated through interactive effects with dynamic environmental drivers. This study used long-term data from two Neotropical lacustrine freshwater systems (Batata Lake, an Amazonian floodplain lake and Imboassica lagoon, an Atlantic coastal lagoon) subjected to different kinds of environmental fluctuations (i.e., flood pulse and sandbar opening) and anthropogenic impacts (i.e., siltation and eutrophication). Our objective was to determine whether the effects of human perturbations are contingent on modifications of important biotic and abiotic characteristics through environmental variability. For both ecosystems, environmental variability consistently interacted with anthropogenic perturbations to alter most of the variables analyzed, such as nutrient dynamics, chlorophyll-a concentration, zooplankton and benthic invertebrate species richness, and temporal community stability, which indicates that interactive effects between environmental variability and anthropogenic perturbations may impact a myriad of ecosystem properties. Furthermore, the nature of these interactive effects was highly dependent on the variable considered and on the ecosystem analyzed. For example, at Imboassica lagoon, sandbar openings interacted synergistically with trophic state to increase the phosphorus concentration in the water column. At Batata Lake, flooding generally alleviated the negative effects of siltation on species richness by both diluting inorganic suspended material concentration and by promoting local recruitment from the regional species pool. Such results indicate that our ability to understand and predict the outcome of anthropogenic impacts on inland aquatic systems can be hampered if we consider human stressors as “static” phenomena disconnected from dynamic interactions with major local environmental drivers.  相似文献   
106.
基于"地方感"、"期望理论"两个基本理论,从旅游核心社区居民地方感、旅游发展期望、旅游发展获益感知、旅游发展成本感知以及旅游发展支持度五个结构变量Ⅲ发,通过引入旅游发展期望值作为中介变量,构建居民地方感对旅游发展支持度内部影响机制的理论模型.以世界遗产地几寨沟为实证研究对象,通过验证性因子分析和三阶段结构方程模型的定量分析,校验理论模型中各结构因子、结构因子与其所含维度之间影响路径及其系数,定量测度了居民的旅游发展期望在居民地方感与旅游发展正反影响感知关联中的中介效用和影响机制,及对旅游发展支持度的潜在影响模式.研究结果表明:①居民地方感对居民旅游发展正反影响感知的作用存在差异,地方感对获益感知的作用远大于成本感知.②居民从旅游发展中感知获益有助于他们对当地旅游发展持更积极态度.而成本感知则会产生消极影响.③居民旅游发展期望中介效用的存在性和有效性,居民地方感通过发展期望,强化了对旅游发展影响感知及旅游支持度作用.④发展期望在居民旅游发展正反影响感知两结构模型中的中介效用存在强弱,在感知获益子结构模型的中介作用强于感知成本子模型.  相似文献   
107.
东海蟹类群落结构特征的研究   总被引:30,自引:1,他引:29  
依据1998年5月(春季)、8月(夏季)、11月(秋季)和1999年2月(冬季)在东海26°00′—33°00′N、127°00′E以西海域的蟹类资源调查资料,对东海蟹类群落结构的特征进行了定量分析。结果表明,东海蟹类优势种有双斑、银光梭子蟹、细点圆趾蟹、长手隆背蟹、日本、武士、锈斑、三疣梭子蟹、泥脚隆背蟹、锐刺长蟹和纤手梭子蟹。其中银光梭子蟹、细点圆趾蟹、双斑和三疣梭子蟹是东海蟹类的主要优势种。常见种是艾氏牛角蟹、红星梭子蟹、绵蟹、变态、光掌、十一刺栗壳蟹、七刺栗壳蟹、象牙长螯蟹、卷折馒头蟹、直额、武装筐形蟹和显著琼娜蟹。种类组成特征方面,冬、春季蟹类少数优势种的优势性明显,秋季优势度种间差异不明显。种类数比较:东海南部最多(57种),中部次之(45种),北部最少(仅37种);不同季节间,春季最多(57种),其次是夏季(53种),秋、冬季较少(仅49种);水深越深的水域,种类数越多。多样性比较:冬、春、秋3季,从北到南,蟹类多样性逐渐增高,且随着水深加深而增大;夏季不同,水深小于40m的浅海多样性指数最高。东海蟹类共可分为3个生态类群,即广温广盐生态类群、高温广盐生态类群和高温高盐生态类群。  相似文献   
108.
退牧(耕)还草(林)与甘肃的可持续发展   总被引:1,自引:0,他引:1  
苏孜  孙晓娟 《中国沙漠》2006,26(4):664-669
科学、有序地推进退牧(耕)还草(林)工程,不仅是甘肃生态建设可持续发展最基本的战略任务,而且是实现甘肃社会经济可持续发展的必然选择。本文从政策、管理、农牧户等方面分析了退牧(耕)还草(林)工程实施过程中存在的问题,提出了甘肃省退牧(耕)还草(林)建设要坚持创新性原则、贯彻协同性原则、体现科学性原则,突出地域性特征及建立有效的激励机制等总体思路和具体对策。  相似文献   
109.
Forest management is an important carbon mitigation strategy for developing countries. As demonstrated by the case of Mexico, community forest management is especially effective because it offers tangible local benefits while conserving forests and sequestering carbon. Community forestry receives minimal government support now, but the clean development mechanism (CDM) of the Kyoto Protocol could leverage additional resources to promote the approach in Mexico and elsewhere. We argue that adequately designed and implemented, community forestry management projects can avoid deforestation and restore forest cover and forest density. They comprise promising options for providing both carbon mitigation and sustainable rural development. These kinds of projects should be included in the CDM.  相似文献   
110.
宁夏固原地区山坡地的水分再分配与退耕还林问题   总被引:5,自引:2,他引:3  
张凡  钟军 《中国沙漠》2002,22(2):184-186
宁夏固原地区是我国水土流失最为严重的地区之一。在进行坡耕地退耕还林还草时,应根据土壤的物理特性和山坡地水分再分配的特点,在山顶和山坡,建立以灌木和草类植物为主组成的人工植被;在水分条件较好的沟谷地带,适量建立一定面积以乔木为主的植被。  相似文献   
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