Hunting for Sustainability in Tropical Secondary Forests

Abstract:  The interaction between land-use change and the sustainability of hunting is poorly understood but is critical for sustaining hunted vertebrate populations and a protein supply for the rural poor. We investigated sustainability of hunting in an Amazonian landscape mosaic, where a small human population had access to large areas of both primary and secondary forest. Harvestable production of mammals and birds was calculated from density estimates. We compared production with offtake from three villages and used catch-per-unit-effort as an independent measure of prey abundance. Most species were hunted unsustainably in primary forest, leading to local depletion of the largest primates and birds. The estimated sustainable supply of wild meat was higher for primary (39 kg · km⁻²· yr⁻¹) than secondary forest (22 kg · km⁻²· yr⁻¹) because four species were absent and three species at low abundance in secondary forests. Production of three disturbance-tolerant mammal species was 3 times higher in secondary than in primary forest, but hunting led to overexploitation of one species. Our data suggest that an average Amazonian smallholder would require ≥3.1 km² of secondary regrowth to ensure a sustainable harvest of forest vertebrates. We conclude that secondary forests can sustainably provide only 2% of the required protein intake of Amazonian smallholders and are unlikely to be sufficient for sustainable hunting in other tropical forest regions.     

区域管治中的博弈效应

区域管治是在经济全球化背景下，通过多种利益集团的对话、协调、合作，解决区域内经济社会冲突，增强区域效力，其核心内容是协调和化解区域发展中的各种利益冲突。本文通过引入博弈论分析方法到区域发展研究领域，构造出地方政府-中央政府政策博弈模型、地方政府-土方政府竞合博弈模型、政府-企业-公众冲突模型来分析和描述区域管涌中各利益集团之间的博弈关系和过程，分析这些决策过程中各博弈方相互制约，相互作用的规律和疚，并针对不同的利益博弈类型，提出优化协调方案，为下一步更好地协调各方利益、实施区域管涌、推动区域一体化发展奠定理论基础，也为我国在划定主体功能区后制定差别化的区域管涌政策提供参考。     

降雨条件下边坡裂缝的演化机制及对边坡稳定性影响——以云南省双柏县丁家坟滑坡为例

边坡的失稳与降雨有着密切的关系。以云南省双柏县丁家坟滑坡为例,阐述了降雨条件下边坡裂缝的演化是由于受到地表横向径流和边坡临空条件的影响。这些形成的裂缝又给地表水入渗提供了主要通道,使地表水易到达边坡体内部的软弱结构面,大大降低了边坡体的稳定性。     

再制造的竞争优势博弈

在＂再制造有利可图＂条件下,建立完全信息和不完全信息的动态博弈模型,分析了＂领先者＂和＂追随者＂再制造企业如何获得竞争优势、保持竞争优势和扭转竞争劣势。结果表明：领先者再制造企业可以获得超额利润,积累竞争实力;领先者再制造企业具有＂先发优势＂,保持并扩大竞争优势的概率更大;追随者再制造企业可以借助再制造水平优势,扭转竞争劣势。     

左右岸跨界水污染治理演化博弈与政策路径研究

基于流域跨界水污染问题多关注于上下游矛盾而忽视左右岸的"公地悲剧",本研究构建左、右岸地区和流域政府三方演化博弈模型,探索奖惩、补偿及复合机制下的主体决策和演化格局差异,结合仿真实验给出推动左右岸协同治理政策路径.结果显示,实现左右岸地区达标排放的关键在于显化达标排放收益与超标排放损失.流域政府倾向于选择奖惩或补偿的单一机制,奖惩机制在不同政策组合中显示出必要性,补偿机制具有加快达标决策、减缓超标决策的收敛速度的积极意义.政策路径是首先采取"阶梯惩罚政策"并增加严重超标惩罚额;继而依次增加奖励和惩罚额促成"奖惩机制",或依次增加奖励额和左右岸之间的补偿额促成"补偿机制",同时给出了上述额度的量化表达式.     

基于遗传算法的EMI滤波器自动进化设计

将遗传算法和电路进化设计应用于电源EMI滤波器的优化设计。针对EMI滤波器设计所需满足的各种限制条件,综合考虑滤波器插入损耗、阻抗失配、EMC标准等因素,确定设计优化准则,选择进化算法优选适合的电路拓扑,用遗传算法确定元件参数,实现滤波器自动设计。对遗传算法存在的“早熟”现象提出改进措施。实验验证了该优化设计结果能有效抑制EMI噪声,具有实用意义。     

新经济地理学视阈下云南地缘经济形成机制探讨

以2011年间的数据对云南面向全国的地缘经济现状进行分析,结合新经济地理学中“核心—外围”模型,认为云南地缘空间关系处于多重“核心—外围”结构中.运用新经济地理学理论对滇中城市群空间经济演化和内生机制进行理论研究,为今后云南地区发展提供新理论支撑.     

双积分政策下异质汽车制造商的产量博弈均衡

文章通过对双积分政策下汽车制造商的产量博弈均衡进行建模分析,研究了双积分政策对企业层面异质制造商的产量决策和利润的影响,以及对产业层面新能源汽车和燃油汽车总产量及总产值的影响。研究结果表明:(1)新能源汽车产业向均衡演进过程中,新能源汽车制造商仍具有一定的发展潜力,但未来发展的中坚力量依靠优势燃油汽车制造商,劣势燃油汽车制造商可能会通过提高燃油经济性发展为优势燃油汽车制造商,从而提高优势燃油汽车制造商的燃油汽车总产量,降低劣势燃油汽车制造商的燃油汽车总产量。(2)双积分政策参数对异质制造商产量决策和利润的影响不同:新能源汽车制造商能够从中受益,而劣势燃油汽车制造商面临危机,转危为安的可能方式包括降低平均燃料消耗量和积极探索新能源汽车生产的可能性。对于优势燃油汽车制造商来说,双积分政策的收紧可能导致其转向燃油汽车市场,规制NEV积分价格上限有利于引导优势燃油汽车制造商转向新能源汽车市场。(3)促进新能源汽车规模增长的参数,可能导致总产值下降,政策调整应将规模增长和产值增长作为双目标,避免单一目标可能导致的市场波动。(4)随着双积分政策的收紧,可预见的新能源汽车积分比例要求提高以及平均燃料消耗量标准趋严,将刺激新能源汽车积分需求提升,缓解新能源汽车积分供需失衡问题。考虑到目前NEV积分价格处于低位,合理降低新能源乘用车车型积分有助于限制NEV积分供给。     

农村生活垃圾分类治理的奖惩激励机制——基于复杂网络演化博弈模型

充分考虑农村"熟人社会"特点,首次采用复杂网络演化博弈模型,通过数值仿真分析了声誉损失和奖励政策对农户垃圾分类行为扩散深度的动态影响.结果表明：政府不干预时,垃圾分类将无法在农村自发持续而普遍推广;在一定范围内提高声誉损失或奖励均可显著促进农户分类;仅依靠单一政策,无法实现分类的深度扩散,若依靠声誉损失与奖励相互配合,可实现低政策强度、高扩散深度的合意效果;搭便车收益的提高会抑制垃圾分类扩散深度;注重经验学习和适应能力的EWA学习策略更有助于促进垃圾分类扩散.上述结论广泛适用于分类初始状态、学习能力、人口规模不同的农村,对中国农村垃圾分类具有普遍性的启发意义.最后,提出了充分利用"熟人社会"优势构建与农村社会经济特征相契合的垃圾分类激励政策建议.     

Comparison of conservation metrics in a case study of lemurs

Conservation planning is important to protect species from going extinct now that natural habitats are decreasing owing to human activity and climate change. However, there is considerable controversy in choosing appropriate metrics to weigh the value of species and geographic regions. For example, the added value of phylogenetic conservation‐selection criteria remains disputed because high correlations between them and the nonphylogenetic criteria of species richness have been reported. We evaluated the commonly used conservation metrics species richness, endemism, phylogenetic diversity (PD), and phylogenetic endemism (PE) in a case study on lemurs of Madagascar. This enabled us to identify the conservation target of each metric and consider how they may be used in future conservation planning. We also devised a novel metric that uses a phylogeny scaled according to the rate of phenotypic evolution as a proxy for a species’ ability to adapt to change. High rates of evolution may indicate generalization or specialization. Both specialization and low rates of evolution may result in an inability to adapt to changing environments. We examined conservation priorities by using the inverse of the rate of body mass evolution to account for species with low rates of evolution. In line with previous work, we found high correlations among species richness and PD (r = 0.96), and endemism and PE (r = 0.82) in Malagasy lemurs. Phylogenetic endemism in combination with rates of evolution and their inverse prioritized grid cells containing highly endemic and specialized lemurs at risk of extinction, such as Avahi occidentalis and Lepilemur edwardsi, 2 endangered lemurs with high rates of phenotypic evolution and low‐quality diets, and Hapalemur aureus, a critically endangered species with a low rate of body mass evolution and a diet consisting of very high doses of cyanide.