长白山二道白河森林流域溪流倒木调查研究

溪流倒木是森林生态系统对水生态系统最重要、最直观的输入和干扰之一,也是两系统之间的主要联结,对于溪流生态系统的稳定、水生生物多样性、河槽形态及其变化过程有着重要的作用。重点对长白山北坡溪流倒木现存量进行了调查和研究,在调查的红松阔叶林植被带内４５００ｍ长河道内,共发现溪流倒木４２５株．分属于１７个树种;其中ｌ、ｗ级腐烂占相当大的比重,与林地倒木Ｉ、ｌ级腐烂占忧有所不同,其原因可能与分解环境的不同有关。所有溪流倒木的总材积为７７．９８ｍ＾２,故溪流倒木的现存量为１．７３３ｍ＾３／１００ｍ和１０．８３ｍ＾３／ｈｍ＾２。溪流倒木的树种组成和不同树种的材积与河岸带植被密切相关,但存在差异。研究表明林分形成倒木并进入河流在时间上可能是均匀或随机的,但不同树种间,其形成倒木并进入河流时的树木材积或生长年龄存在较大差异。溪流倒木和林地活立木的个体数量的径级分布基本上为反Ｊ型,而它们材积的径级分布均为典型的Ｊ型。     

Does Forest Scarcity Affect the Collection and Use of Firewood by Rural Communities? A Case Study in the Atlantic Forest of Northeastern Brazil

Many rural communities no longer have abundant forest areas for firewood collection. Based on this scenario, we evaluated how the scarcity of forest environments influences the collection and use of this resource in rural areas. A community located in the Atlantic Forest region of northeastern Brazil, which already lacks forest areas for firewood, was selected for field research. We observed that despite this context of forest scarcity, firewood remains the main source of fuel energy in the community. In total, 27 species of wood were cited, with an emphasis on exotic species in terms of number of citations. The perceived wood quality explained the frequency of plant use, but not the number of consumers. This can be explained by the difficulty of access to some species considered of better quality, because in the studied region, the plants are usually collected in private areas. Efforts in conservation strategies are recommended to encourage an increase in the frequency of use of the available exotic species in order to safeguard the native ones.     

Biotechnological efforts for preserving and enhancing temperate hardwood tree biodiversity,health, and productivity

Hardwood tree species in forest, plantation, and urban environments (temperate regions of the world) are important biological resources that play a significant role in the economy and the ecology of terrestrial ecosystems, and they have aesthetic and spiritual value. Because of these many values of hardwood tree species, preserving forest tree biodiversity through the use of biotechnological approaches should be an integral component in any forestry program in addition to large-scale ecologically sustainable forest management and preservation of the urban forest environment. Biotechnological tools are available for conserving tree species as well as genetic characterization that will be needed for deployment of germplasm through restoration activities. This review concentrates on the biotechnological tools available for conserving, characterizing, evaluating, and enhancing hardwood forest tree biodiversity. We focus mainly on species grown for lumber and wood products, not species grown mainly for fiber (pulp and paper production). We also present a brief summary of the importance of non-wood forest products from temperate hardwood tree species (a research area that needs further development using biotechnological techniques) and a few case studies for preserving forest tree biodiversity.     

Liquified Petroleum Gas (LPG) Supply and Demand for Cooking in Northern Ghana

Like many other countries, Ghana relies on biomass (mainly wood and charcoal) for most of its cooking needs. A national action plan aims to expand liquefied petroleum gas (LPG) access to 50% of the country’s population by 2020. While the country’s southern urban areas have made progress toward this goal, LPG use for cooking remains low in the north. The aim of this cross-sectional study was to characterize the current state of the LPG market in this area and examine opportunities and barriers to scale up LPG adoption. We interviewed 16 LPG suppliers (stove, cylinder, and fuel vendors) as well as 592 households in the Kassena-Nankana Districts (KND) of Ghana. We find large rural–urban differences in LPG uptake: less than 10% of rural households own LPG stoves compared with over half of urban households. Awareness of LPG is high across the region, but accessibility of fuel supply is highly limited, with just one refilling station located in the KND. Affordability is perceived as the main barrier to LPG adoption, and acceptability is also limited by widespread concerns about the safety of cooking with LPG. Transitioning to a cylinder recirculation model, and providing more targeted subsidies and credit options, should be explored to expand access to cleaner cooking in this region.     

基于生态足迹的大学食堂餐具生态影响分析

以生态足迹为定量分析方法,以广州大学食堂为例,分析计算了一次性餐具和公用餐具对生态环境的影响,并比较分析了各种型号的餐具生态足迹.分析了一次性餐具和公用餐具生产过程中的原料消耗及能耗.广州大学食堂所用的餐具主要为塑料制餐具、不锈钢餐具、木制和竹制筷子.消耗的资源主要为钢铁、乙烯、木材和竹材等,可归于化石能源地足迹和林地足迹.调查了公用餐具洗涤过程中的资源消耗,主要为洗涤过程中的水电消耗以及废水处理能耗,可归于化石能源地足迹和可耕地足迹.最后结合学校食堂餐具的使用方案,计算了一次性餐具和公用餐具(以1a为限)的生态足迹.研究表明,公用餐具组合的足迹为3.7236×10-3gm2(全球平方米,记为gm2),使用竹筷的一次性餐具组合足迹为2.2085×10-2 gm2,使用木筷一次性餐具组合足迹为9.3781×10-2gm2.公用餐具足迹是一次性餐具的3.97%～16.8%.此外,由于竹筷的足迹是木筷23.55%,因此使用竹筷能大大降低一次性餐具对生态的影响.     

Wood fuel consumption,institutional quality,and forest degradation in sub-Saharan Africa: Evidence from a dynamic panel framework

The objective of this paper is to answer an empirical question regarding whether wood fuel consumption and institutional quality affect forest degradation in sub-Saharan Africa. To accomplish this, a sample of 45 sub-Saharan African countries covering 2005–2013 was employed. Also, the dynamic generalized method of moments (GMM) approach was used to estimate the specified model. The results indicated that wood fuel consumption significantly contributed to forest degradation in the region. On the other hand, control of corruption and government effectiveness were negatively related to forest degradation. This suggests that effective control of corruption and governance can contribute to lowering forest degradation in the region. Forest degradation aided by wood fuel consumption can be lessened by effective control of corruption and governance. Thus, policy makers should (1) provide adequate and affordable (or subsidized) modern fuels to the populace, especially rural dwellers, (2) intensify the fight against corruption, and (3) ensure effective governance.     

The occurrence of myxomycetes in wood

Although the fruiting bodies of myxomycetes are commonly found associated with coarse woody debris in forest ecosystems throughout the world, there is no direct evidence that these organisms actually live within wood. In the research reported herein, surface sterilisation of pieces of wood taken from the branches of eight different tree species and the subsequent culturing of slivers of wood collected from within the interior of those branches clearly revealed the presence of the amoeboflagellates of myxomycetes. No evidence of the occurrence of plasmodia within wood was found, but amoeboflagellates emerged from 47 % of the wood slivers placed in culture.     

Use patterns and value of Savanna resources in three Rural villages in South Africa

Rural communities in South Africa harvest a diversity of wild resources from communal woodlands for home consumption and sale. The contribution these resources make to the rural economy has been little recognized, and few studies have attempted to place a monetary value on this use. This paper describes three case studies which aimed to determine the value of savanna resources for the livelihoods of rural households. Use patterns and values of resources in three villages of differing socioeconomic status were determined using household interviews, PRA techniques and key informant interviews. Questions were designed to establish the types of products used, frequency of use, quantities used, seasonality of use, longevity of durable resources, local prices, and the extent of trade. All households were procuring at least some woodland resources, with the most frequently used being fuel wood, wood for implements, edible herbs and fruits, grass for brushes, and insects. Patterns of resource use varied across villages. The most “rural” village used the greatest diversity of resources and had the highest number of users for most resources. Gross value of resources consumed per household per year ranged from R28I9 to R7238. Total value was highest in the less obviously resource dependent village, primarily the result of higher local prices due to greater extraction costs and a larger market for traded goods. Values are comparable to those contributed by other land-based livelihood activities such as subsistence cultivation and livestock production.     

农户薪柴消费的理论模型及实证研究

农户薪柴消费变化对室内空气质量、农村生态环境建设影响重大,论文构建了山区农户薪柴消费的理论模型,以重庆市典型区1015份农户调查数据为例,运用Tobit模型分析了农户人均薪柴消费量的影响因素。研究表明:农户家庭能源消费中,商品能源和新能源的比重逐步增大,但薪柴依旧是农户普遍使用的能源类型,且消费量占总能源消费量的比重高;通过降低农业劳动力比重和提高非农工资水平两种途径,非农就业能显著降低农户人均薪柴消费量;家庭电器数量增多、其他收入(政府补贴、亲戚帮扶等)增加、及替代能源(液化气、沼气、煤炭等)可获得性增强也能显著降低农户人均薪柴消费量,而户主年龄大、人均牲畜数量多及房屋离集市距离远的农户家庭的人均薪柴消费量高。提出了加快薪柴替代的措施。     

基于生态系统服务价值的生态足迹模型均衡因子及产量因子测算

均衡因子和产量因子是生态足迹模型中的关键参数,现有的测算方法多根据物质生产和消费实现,忽略生态系统提供服务的能力。本研究提出基于生态系统服务价值的均衡因子和产量因子测算方法,并以1990、2005和2015年北京市门头沟区为例,研究生态涵养发展区生态承载力,并与通用因子计算结果对比。结果表明:(1)基于生态系统服务价值获取的均衡因子:水域林地耕地。水域均衡因子最高,平均值达到8.37。耕地均衡因子最低,平均值仅为0.24。林地均衡因子高于耕地,均衡因子平均值为0.71。说明该方法较好的表现了不同生态系统提供生态服务能力的差异;(2)基于该研究方法获取的不同生态系统的产量因子接近:耕地林地水域,均值分别为0.90,0.87和0.86,且呈逐年递减趋势;(3) 1990年到2015年,门头沟区生态承载力先降低后提高,生态足迹先提高,再降低,2005年出现生态赤字,其森林、耕地和区域生态承载力与生态足迹小于通用因子生态足迹模型结果,水域生态承载力和生态足迹高于通用因子生态足迹模型结果。与通用因子相比,基于生态系统服务价值的均衡因子和产量因子更好的体现了研究区内各类生态系统生态服务的承载力。     

Recent land‐use changes affect stream ecosystem processes in a subtropical island in Brazil

Land‐use changes such as conversion of natural forest to rural and urban areas have been considered as main drivers of ecosystem functions decline, and a large variety of indicators has been used to investigate these effects. Here, we used a replicated litter‐bag experiment to investigate the effects of land‐use changes on the leaf‐litter breakdown process and leaf‐associated invertebrates along the forest–pasture–urban gradient located in a subtropical island (Florianópolis, SC, Brazil). We identified the invertebrates and measured the litter breakdown rates using the litter bags approach. Litter bags containing 3 g of dry leaf of Alchornea triplinervia were deployed on forest rural and urban streams. Principal component analysis, based on physico‐chemical variables which, confirmed a gradient of degradation from forest to urban streams with intermediate values in rural areas. In accordance, shredder richness and abundance were lower in rural and urban than in forest streams. The land‐use changes led also to the dominance of tolerant generalist taxa (Chironomidae and Oligochaeta) reducing the taxonomic and functional diversity in these sites. Leaf‐litter breakdown rates decreased from forest to rural and finally to urban areas and were associated with changes in pH, water velocity, dissolved oxygen and abundance of leaf‐shredding invertebrates, although global decomposition rates did not differ between rural and urban streams. Overall, this study showed that land‐use changes, namely to rural and urban areas, have a strong impact on tropical streams ecosystems, in both processes and communities composition and structure. Despite of being apparently a smaller transformation of landscape, rural land use is comparable to urbanisation in terms of impact in stream functioning. It is thus critical to carefully plan urban development and maintain forest areas in the island of Florianópolis in order to preserve its natural biodiversity and aquatic ecosystems functioning.     

山东半岛城市扩展模式与生态足迹的关系

理解城市扩展模式与生态足迹动态之间的关系是区域可持续性研究的重要内容,对实现城市可持续发展具有重要指导意义。然而,目前对这二者关系探索的实证研究较少。以山东半岛城市群为例,掌握其2000—2010年的城市扩展模式与生态足迹动态特征,并探索二者之间的关系。采用景观扩展指数和生态足迹模型对研究区的城市扩展模式和生态足迹动态进行计算。在此基础上,将该区44个县划分为4种类型,用相关分析法对城市扩展模式和生态足迹动态的关系进行探索。结果表明,2000—2010年山东半岛城市群的城市用地面积增量加了1.2×10~5hm~2,增幅为19.4%。44个县均体现出边缘型扩展面积最大,生态赤字增加的特点,平均赤字增量为1.26 hm~2/人。垦利等27个县的外延式扩展面积与生态赤字增加量存在较显著的正相关关系,在济阳等17个县中,二者未呈现出相关关系。建议垦利、淄博和青岛等地区在未来城市发展中,控制飞地型和边缘型扩展面积总量,发展清洁能源,遏制化石能源足迹的增长趋势。     

Household Determinants of Liquified Petroleum Gas (LPG) as a Cooking Fuel in SW Cameroon

Currently 70% of the population in Cameroon are reliant on solid fuel for cooking (90% in rural communities) and the associated household air pollution contributes to significant mortality and morbidity in the country. To address the problems of energy security, deforestation and pollution the government has developed a strategy (Masterplan) to increase use of liquified petroleum gas (LPG) as a cooking fuel from 12% to 58% by 2030. As a clean fuel scaled adoption of LPG has the potential to make significant positive impacts on population health. The LPG Adoption in Cameroon Evaluation (LACE) studies are assessing in the community (i) barriers and enablers for and (ii) local interventions to support, adoption and sustained use of LPG. A census survey conducted for LACE in rural and peri-urban regions of SW Cameroon provided an opportunity to investigate current fuel use patterns and factors associated with primary and exclusive use of LPG. A cross-sectional survey of 1577 households (1334 peri-urban and 243 rural) was conducted in March 2016 using standardised fuel use and household socio-demographic questions, administered by trained fieldworkers. Wood (40.7%) and LPG (51.1%) were the most frequently reported fuels, although the dominant fuels in rural and peri-urban communities were wood (81%) and LPG (58%) respectively. Fuel stacking was observed for the majority of LPG using households (91% of peri-urban and 99% of rural households). In rural homes, a higher level of education, access to sanitation and piped water and household wealth (income and asset ownership) were all significantly associated with LPG use (p < 0.05). In peri-urban homes, younger age, access to sanitation and piped water and increasing education were significantly associated with both any and exclusive use of LPG (p < 0.05). However, whilst household wealth was related to any LPG use, there was no relationship with exclusive use. Results from this census survey of a relatively well-established LPG market with lower levels of poverty and high levels of education than Cameroon as a whole, find LPG usage well below target levels set by the Cameroon government (58% by 2030). Fuel stacking is an issue for the majority of LPG using households. Whilst, as observed here, education, household wealth and socio-economic status are well recognised predictors of adoption and sustained use of clean modern fuels, it is important to consider factors across the whole LPG eco-system when developing policies to support their scaled expansion. A comprehensive approach is therefore required to ensure implementation of the Cameroon LPG Masterplan achieves its aspirational adoption target within its stated timeframe.     

Urbanization and fragmentation have opposing effects on soil nitrogen availability in temperate forest ecosystems

Nitrogen (N) availability relative to plant demand has been declining in recent years in terrestrial ecosystems throughout the world, a phenomenon known as N oligotrophication. The temperate forests of the northeastern U.S. have experienced a particularly steep decline in bioavailable N, which is expected to be exacerbated by climate change. This region has also experienced rapid urban expansion in recent decades that leads to forest fragmentation, and it is unknown whether and how these changes affect N availability and uptake by forest trees. Many studies have examined the impact of either urbanization or forest fragmentation on nitrogen (N) cycling, but none to our knowledge have focused on the combined effects of these co-occurring environmental changes. We examined the effects of urbanization and fragmentation on oak-dominated (Quercus spp.) forests along an urban to rural gradient from Boston to central Massachusetts (MA). At eight study sites along the urbanization gradient, plant and soil measurements were made along a 90 m transect from a developed edge to an intact forest interior. Rates of net ammonification, net mineralization, and foliar N concentrations were significantly higher in urban than rural sites, while net nitrification and foliar C:N were not different between urban and rural forests. At urban sites, foliar N and net ammonification and mineralization were higher at forest interiors compared to edges, while net nitrification and foliar C:N were higher at rural forest edges than interiors. These results indicate that urban forests in the northeastern U.S. have greater soil N availability and N uptake by trees compared to rural forests, counteracting the trend for widespread N oligotrophication in temperate forests around the globe. Such increases in available N are diminished at forest edges, however, demonstrating that forest fragmentation has the opposite effect of urbanization on coupled N availability and demand by trees.     

Evaluating the relationship between natural resource management and agriculture using embodied energy and eco-exergy analyses: A comparative study of nine countries

By shifting from animate labor to ever-increasing fossil fuel and other supplement energy subsidies, energy use in human food supply systems continues to increase. As agriculture is the fundamental manner in which humans interact with the environment, it is especially important to understand the relationships between humans, energy, and food. Many researchers evaluate the material and energy resources involved in the food production chain. Energy return on energy investment (EROI) analyses have been particularly useful in assessing the quantity of energy dissipated versus the energy eventually acquired, thus helping to evaluate the overall efficiency of human food systems (i.e., energy invested versus dietary Calories harvested). A complimentary measure, eco-exergy, has been used to evaluate the quality of energies dissipated and generated in ecosystems. To deepen our insight into the dynamic between humans and their food system, we combine these two measures for a food production analysis. Focusing on meat production, adjusted EROI and eco-exergy ratios are used to evaluate both the quantity and quality of energy accumulated and dissipated in nine country's agricultural processes. Each country's food production indicators are then compared with more established methods of sustainability measurement including ecological footprint and biocapacity. The results reveal a significant, highly correlated relationship between these food production indicators and each country's ecological footprint (resources being consumed) while also showing no correlation to their respective biocapacity (resources actually available), thus quantifying a food production disconnect from the local ecosystem. Using these new metrics, we evaluate which changes in each country's food system could result in more environmentally balanced practices, and also how these changes can be realized.     

A Systematic Review on the Contributions of Edible Plant and Animal Biodiversity to Human Diets

The sustainable use of natural and agricultural biodiversity in the diet can be instrumental to preserve existing food biodiversity, address malnutrition, and mitigate adverse effects of dietary changes worldwide. This systematic review of literature summarizes the current evidence on the contribution of plant and animal biodiversity to human diets in terms of energy intake, micronutrient intake, and dietary diversification. Peer-reviewed studies were searched in ten databases using pre-defined search terms. Only original studies assessing food biodiversity and dietary intake were included, resulting in a total of 34 studies. 7, 14, and 17 studies reported information in relation to energy intake, micronutrient intake, and dietary diversification, respectively. In general, locally available foods were found to be important sources of energy, micronutrients, and dietary diversification in the diet of particularly rural and forest communities of highly biodiverse ecosystems. The current evidence shows local food biodiversity as important contributor of nutritious diets. Findings are, however, limited to populations living in highly biodiverse areas. Research on the contribution of biodiversity in diets of industrialized and urban settings needs more attention. Instruments are needed that would more appropriately measure the dietary contribution of local biodiversity.     

The causes and consequences of deforestation among the prehistoric Maya

The collapse of the Classic Maya state is investigated from an ecological perspective. Settlement and palynological data from the Maya center of Copan, Honduras, are presented which indicate that substantial clearing of the upland pine forest had occurred prior to and during the abandonment of that urban center. A comparative use- rate analysis suggests that the increased clearing of pine was primarily caused by demands for domestic fuel wood by an expanding urban population. This forest mismanagement is directly linked to accelerated erosion rates which are considered primary elements in the collapse of the Maya state.     

台州市城市生态足迹

城市生态足迹分析可定量反映城市人类活动对自然生态环境产生的压力和影响程度,这种方法为城市生态系统研究提供了新的思路和研究方向。本文在介绍生态足迹的理论和计算模型的基础上,以台州市为例,计算了台州市2002年的生态足迹。结果表明,2002年台州市生态足迹为1．33084hm^2·人^-1,可利用的生态承载力为0．25800hm^2·人^-1,生态赤字为1．07284hm^2·人^-1,反映了台州市的生产、生活强度超过了生态系统的承载能力。因此,台州市需注重提高其资源利用效率,提倡节约型的生产和生活消费模式,减少其生态足迹,通过生态城市建设,实现城市的可持续发展。     

Reconstructing Anthropogenic Disturbance Regimes in Forest Ecosystems: A Case Study from the Swiss Rhone Valley

Anthropogenic disturbances of forest ecosystems are increasingly recognized as fundamental ecological processes with important long-term implications for biogeochemical cycles and vegetation patterns. This article aims at reconstructing the extent and intensity of the two most common types of traditional forest uses—forest litter collecting and wood pasture—in the Swiss Rhone valley (Valais) by (i) identifying the spatiotemporal patterns, and (ii) modeling the biomass removal through these practices. Detailed information on agricultural practices and socio-economic context were essential to develop reliable estimates of anthropogenic disturbance regimes. In the Valais, predominately goats and sheep grazed in the forests. The intensity of grazing was a function of the number of grazing animals and the available grazing area. Forest litter was used as bedding for farm animals during the winter. Key factors determining the intensity of litter collecting were the number of animal units, the amount of available substitute products (straw), and the area where litter raking could be practiced. The results show that wood pasture and forest litter collecting were practiced on a significant proportion of the forested landscape in the Valais up to the second half of the 20th century. Until the implementation of forest management plans in the 1930s, almost half of the forests in the study area were affected by wood pasture and/or forest litter collecting. The regulations in the management plans led to an essential reduction of the area available for these traditional practices but likewise to an increased pressure on the remaining areas. The results suggest that the notion of a slow but steady disappearance of traditional non-timber forest uses and the associated effects on forest ecosystems is oversimplified. Quantitative reconstructions of biomass output resulting from these practices confirm the importance of traditional non-timber forest uses for ecosystem development in this region. Furthermore, it is very likely that similar effects have been widespread throughout regions with similar natural and socio-economic context, for example, throughout a significant proportion of the European Alps. This study underlines the importance of environmental history for ecological sciences as well as for forest management and conservation planning.     

泡桐属(Paulownia)花粉形态学的初步研究

泡桐属(Paulownia)花粉,均为近球形,具3(拟)孔沟,外壁外层有清楚的异胞网状雕纹,沟界极区明显。这些共同特征,说明泡桐属是一个种间亲缘极近的自然的属;其萌发孔类型,可作为泡桐属归入玄参科的证据之一。通过花粉形态的比较,对兰考泡桐、宜昌泡桐和建始泡桐的分类地位,提出了论证。