Fluvial perturbance in the Western Amazon basin: regulation by long-term sub-andean tectonics

Haffer's refuge theory proposes that during the arid climatic phases of the late Pleistocene, tropical lowland forests of Amazonia were reduced to isolated patches contributing to the high species richness of the present-day forest. The theory was developed because no obvious historic or modern geomorphic isolation barriers were recorded in Amazonia. Analyses of radar images combined with stratigraphical data show that in the basinal forelands of the tectonically active Andes the geological setting causes long-term fluvial perturbance. This leads to a temporally structured highly complex mosaic of fossil and present floodplains. These dynamics have been present with varying activity and geographic range during the Tertiary and Quaternary, providing site-turnover that has not been recognized by the biogeographic tradition of the Amazon basin.     

基于SWOT分析吉林西部森林生态发展的研究——以X乡为例

运用SWOT方法对吉林省西部X乡森林生态发展的内部优势、劣势,外部机遇以及威胁四个方面进行分析,结合该乡的森林资源特点、经营管理存在的问题,从而提出X乡森林生态可持续发展的几点思考。     

Dissecting amazonian biodiversity

Biogeographical and biodiversity studies in Iowland Amazonian rain forests typically refer to observed or postulated distribution barriers such as past unfavorable climates, mountains, rivers, and river floodplains that divide the uniform tierra firme (noninundated) forest. Present-day ecological heterogeneity within tierra firme has hardly been discussed in this context, although edaphic differences are known to affect species distribution patterns in both inundated areas and tierra firme. Quantification of landscape heterogeneity in Peruvian Iowland Amazonia (500,000 kilometers squared), based on field studies and satellite image analysis, shows that Peruvian Amazonia is considerably more heterogeneous than previously reported. These observations have implications for the research, management, and conservation of Amazonian biodiversity.     

The 2010 Amazon drought

In 2010, dry-season rainfall was low across Amazonia, with apparent similarities to the major 2005 drought. We analyzed a decade of satellite-derived rainfall data to compare both events. Standardized anomalies of dry-season rainfall showed that 57% of Amazonia had low rainfall in 2010 as compared with 37% in 2005 (≤-1 standard deviation from long-term mean). By using relationships between drying and forest biomass responses measured for 2005, we predict the impact of the 2010 drought as 2.2 × 10(15) grams of carbon [95% confidence intervals (CIs) are 1.2 and 3.4], largely longer-term committed emissions from drought-induced tree deaths, compared with 1.6 × 10(15) grams of carbon (CIs 0.8 and 2.6) for the 2005 event.     

四川镇龙山国家森林公园生态旅游SWOT分析及发展策略

根据四川镇龙山国家森林公园生态旅游的开发现状,运用SWOT分析法分析其存在的优势、劣势及面临的机遇和威胁,并在此基础上提出相应的发展策略。     

Millennial-scale dynamics of southern Amazonian rain forests

Amazonian rain forest-savanna boundaries are highly sensitive to climatic change and may also play an important role in rain forest speciation. However, their dynamics over millennial time scales are poorly understood. Here, we present late Quaternary pollen records from the southern margin of Amazonia, which show that the humid evergreen rain forests of eastern Bolivia have been expanding southward over the past 3000 years and that their present-day limit represents the southernmost extent of Amazonian rain forest over at least the past 50,000 years. This rain forest expansion is attributed to increased seasonal latitudinal migration of the Intertropical Convergence Zone, which can in turn be explained by Milankovitch astronomic forcing.     

The response of vegetation on the Andean flank in western Amazonia to Pleistocene climate change

A reconstruction of past environmental change from Ecuador reveals the response of lower montane forest on the Andean flank in western Amazonia to glacial-interglacial global climate change. Radiometric dating of volcanic ash indicates that deposition occurred ~324,000 to 193,000 years ago during parts of Marine Isotope Stages 9, 7, and 6. Fossil pollen and wood preserved within organic sediments suggest that the composition of the forest altered radically in response to glacial-interglacial climate change. The presence of Podocarpus macrofossils ~1000 meters below the lower limit of their modern distribution indicates a relative cooling of at least 5°C during glacials and persistence of wet conditions. Interglacial deposits contain thermophilic palms suggesting warm and wet climates. Hence, global temperature change can radically alter vegetation communities and biodiversity in this region.     

The global extent and determinants of savanna and forest as alternative biome states

Theoretically, fire-tree cover feedbacks can maintain savanna and forest as alternative stable states. However, the global extent of fire-driven discontinuities in tree cover is unknown, especially accounting for seasonality and soils. We use tree cover, climate, fire, and soils data sets to show that tree cover is globally discontinuous. Climate influences tree cover globally but, at intermediate rainfall (1000 to 2500 millimeters) with mild seasonality (less than 7 months), tree cover is bimodal, and only fire differentiates between savanna and forest. These may be alternative states over large areas, including parts of Amazonia and the Congo. Changes in biome distributions, whether at the cost of savanna (due to fragmentation) or forest (due to climate), will be neither smooth nor easily reversible.     

Amazonia through time: Andean uplift, climate change, landscape evolution, and biodiversity

The Amazonian rainforest is arguably the most species-rich terrestrial ecosystem in the world, yet the timing of the origin and evolutionary causes of this diversity are a matter of debate. We review the geologic and phylogenetic evidence from Amazonia and compare it with uplift records from the Andes. This uplift and its effect on regional climate fundamentally changed the Amazonian landscape by reconfiguring drainage patterns and creating a vast influx of sediments into the basin. On this "Andean" substrate, a region-wide edaphic mosaic developed that became extremely rich in species, particularly in Western Amazonia. We show that Andean uplift was crucial for the evolution of Amazonian landscapes and ecosystems, and that current biodiversity patterns are rooted deep in the pre-Quaternary.     

Explaining the abundance of ants in lowland tropical rainforest canopies

The extraordinary abundance of ants in tropical rainforest canopies has led to speculation that numerous arboreal ant taxa feed principally as "herbivores" of plant and insect exudates. Based on nitrogen (N) isotope ratios of plants, known herbivores, arthropod predators, and ants from Amazonia and Borneo, we find that many arboreal ant species obtain little N through predation and scavenging. Microsymbionts of ants and their hemipteran trophobionts might play key roles in the nutrition of taxa specializing on N-poor exudates. For plants, the combined costs of biotic defenses and herbivory by ants and tended Hemiptera are substantial, and forest losses to insect herbivores vastly exceed current estimates.     

云南磨盘山国家森林公园生态旅游的SWOT分析及发展策略

根据云南磨盘山国家森林公园生态旅游的开发现状,运用SWOT分析方法分析其存在的优势和劣势以及面临的机遇和威胁,并在此基础上提出相应的发展策略。     

热带雨林景观空间异质性分析——铜壁关自然保护区森林景观范例

通过航空遥感图像、森林分布图和土地利用数据,对云南铜壁关自然保护区森林景观进行研究,测定该保护区森林景观的空间异质性.结果显示:该地森林景观由16种组分组成.其中,季风常绿阔叶林和热带山地雨林斑块占优势,但斑块破碎度较高,且相互隔离,呈孤岛状;几大森林斑块间应建立生物廊道,促进物种交流;保护区中尚存一定的农地斑块,人类活动频繁,是保护对象的潜在威胁;应进行退耕还林,促进其自然生境的恢复.     

云南省森林碳汇项目的SWOT分析和应对策略

运用SWOT分析法,分别对云南森林碳汇项目的内部优势、劣势,外部机遇和威胁进行分析,结果表明:云南在经济环境和实践经验方面有优势,在社会参与程度、项目规模和碳汇人才等方面存在劣势,在国际气候环境、国内政策等方面存在机遇,在项目计入期和森林资源保护等方面存在威胁。进一步提出,云南可以通过改变开展森林碳汇项目的参与模式、采用合适的交易方式、熟悉森林碳汇项目的有关规则、加强对森林碳汇理论的宣传和研究、加强对碳汇林的管理和扩大森林碳汇项目的规模等措施,提升云南森林碳汇项目的市场竞争力。     

紫蓬山国家森林公园生态旅游业的SWOT分析

采用SWOT分析法较为详细地分析了紫蓬山国家森林公园发展生态旅游业的优势、弱势、机遇和威胁,包括区位优势、动植物资源优势、气候优势和开发潜力等优势,生态旅游的兴起、生态工程的实施,旅游专业人才缺乏、管理和服务滞后等因素;并以此为基础,进一步提出了相应的发展建议,主要有开发与保护并重、适当开发森林生态旅游资源、开发生态旅游产品、加强宣传营销工作、积极进行人才的培训与引进、努力提高管理水平和服务水平以及完善景区的旅游基础设施建设等。     

城区山岳型森林公园发展策略研究——以广东省云浮东山森林公园为例

以广东云浮东山森林公园为例,分析城区山岳型森林公园的特点,运用SWOT分析法分析其发展中存在的优势和劣势及面临的机遇和挑战,并提出相应的发展策略.     

Colonist farmers' perceptions of fertility and the frontier environment in eastern Amazonia

Colonists, unlike indigenous peoples, are often assumed tohave little knowledge of their environment. However, their perceptions of the environment and their knowledgeof natural resource systems have a significant impact on their farming practices. Farmers in the frontier regionof Marabá, Eastern Amazonia, understand nutrient cycling and the links between different components in farmingsystems. Diagrams drawn by farmers show very diversified systems, and farmers' knowledge of soilcharacteristics, including sub-surface features, and distribution in their localities is very detailed in comparison to pedologicalclassifications. However, knowledge about nutrient cycling is very uneven, even between farmers from the same area.Generally, farmers were found to have very detailed knowledge of environmental resources, but very patchyknowledge of processes and functions underlying systems, and this conforms to evolutionary models of ecologicalknowledge. Perceptions of change in soil fertility are related to the length of settlement, and are closelylinked to the presence of forest. Overall, the majority of farmers believe they will not be able to sustain cropping in thefuture, and as forest and fallow become scarce the most feasible option will be for them to move to other areas.Farmers are more optimistic about pasture, which is viewed as a more stable system, with the key to long-termsustainability being weed control. These findings imply that a high degree of information sharing between farmers andscientists is required to establish resource management strategies and social institutions to supportsustainable development strategies at the frontier.     

京津冀一体化背景下怀柔都市农业发展战略研究

为促进城乡和谐发展、农民增收致富,在京津冀一体化背景下,针对怀柔都市农业发展现状,运用SWOT分析法对怀柔都市农业发展所具有的优势、劣势及外部面临的机遇、威胁进行系统分析,指出了怀柔区都市农业发展的优势是冷水鱼产业、林果产业、设施蔬菜产业等发展日趋规模化与品牌化,但是存在着资源利用效率低、生态产业比重小、深山区休闲农业发展缓慢等劣势,应抓住京津冀一体化发展以及当前休闲需求快速发展等机遇,迎接由资源环境、土地制度等带来的挑战。最后提出生态优先、农村一二三产融合、做大做强农村文化产业等怀柔都市农业发展战略,为怀柔未来都市农业发展提供可行建议。     

台湾碳税财政支付移转至农业部门之最适策略——基于可计算一般均衡模型(CGE)的运用

由于人为排放的二氧化碳等温室气体,引起了全球暖化,威胁到了人类的生存,以低能耗、低污染、低排放为基础的低碳经济模式的革命是拯救人类群体社会永续生存的机会。目前台湾在CO2减量的策略除了调整产业政策与产业结构、提升能源效率之外,厚植台湾地区的森林资源,大规模推动农业生产用地用于造林碳汇,以及加入国际森林资源碳交易市场,亦为未来温室气体减量策略的可行方案。该文以台湾社经资料为基础,运用可计算一般均衡模型(CGE)推算各种碳税政策对于产业最终需求结构变动及个别产业产出之影响,找出台湾碳税财政支付移转至农业部门之最适策略组合。     

森林保险保费补贴政策的林业产出规模效应实证分析——基于双重差分模型与事件研究模型

森林保险保费补贴政策在中国实施已超10 a,其能否和在多大程度上促进林业生产的命题亟待科学系统的实证考查。为此,特结合生产者行为理论探寻森林保险保费补贴政策的林业产出规模效应,剖析森林保险保费补贴政策对林业产出的作用机理。在此基础上,基于2001—2017年中国31个省区市的面板数据,以2009年森林保险保费补贴政策冲击为自然实验,综合运用双重差分模型与事件研究模型实证分析该补贴政策对林业产出的影响及其长期动态影响效果,并进行2项安慰剂实验以排除研究结论的2个潜在威胁。结果表明:森林保险保费补贴政策对林业第一产业涉林产值有显著(P<0.1)正向影响,且影响效果随政策实施时间的推进而不断增强。补贴政策实施后,试点省较非试点省区市的林业第一产业涉林产值平均增加了104万元。以2010年为政策冲击年进行稳健性检验,所得结论与以2009年为政策冲击年进行分析的结果一致。安慰剂实验的结果排除了本研究结论的2个潜在威胁。研究结果对中央财政补贴下森林保险的作用持肯定态度,建议应从补贴对象瞄准、补贴规模科学测算、补贴标准合理设定等方面优化森林保险保费补贴政策,以增强其产出效应。     

Deforestation, livelihoods, and the preconditions for sustainable management in Olancho, Honduras

Growth of the national cattle herd is contributing to rapid and inappropriate deforestation in Honduras. Field research was conducted in the Department of Olancho to better understand this problem and to assess the possibilities for local interest in forest protection. A recent upsurge in the profitability of cattle farming bodes badly for the forest, but three countervailing factors could ultimately serve as the basis for community-based forest management. First, area residents have a greater appreciation for the economic and ecological functions of the forest than one might surmise, given the rapid pace of deforestation. Second, timber is a significant source of community income, thus there may be latent incentives to maintain supplies in the long term. Third, some residents will not turn to cattle farming, in spite of its profitability, perhaps because of their dependence on timber marketing. Policies enacted in 1992 undermine theseincipient incentives for forest custodianship. Inappropriate deforestation can be lessened through policy reforms thatwould enable smallholders to conserve and manage their resources over the long-term.