Gathering “wild” food in the city: rethinking the role of foraging in urban ecosystem planning and management

Recent “green” planning initiatives envision food production, including urban agriculture and livestock production, as desirable elements of sustainable cities. We use an integrated urban political ecology and human–plant geographies framework to explore how foraging for “wild” foods in cities, a subversive practice that challenges prevailing views about the roles of humans in urban green spaces, has potential to also support sustainability goals. Drawing on research from Baltimore, New York City, Philadelphia, and Seattle, we show that foraging is a vibrant and ongoing practice among diverse urban residents in the USA. At the same time, as reflected in regulations, planning practices, and attitudes of conservation practitioners, it is conceptualised as out of place in urban landscapes and an activity to be discouraged. We discuss how paying attention to urban foraging spaces and practices can strengthen green space planning and summarise opportunities for and challenges associated with including foragers and their concerns.     

Does Riparian Forest Restoration Thinning Enhance Biodiversity? The Ecological Importance of Large Wood

Intact riparian ecosystems are rich in biological diversity, but throughout the world, many have been degraded. Biodiversity declines, particularly of vertebrates, have led to experimental efforts to restore riparian forests by thinning young stands to accelerate creation of large diameter live trees. However, many vertebrates depend on large diameter deadwood that is standing as snags or fallen to the forest floor or fallen into streams. Therefore, we reviewed the sizes of deadwood and live trees used by different vertebrate species to understand which species are likely to benefit from different thinning treatments. We then examined how riparian thinning affects the long‐term development of both large diameter live trees and deadwood. To this end, we used a forest growth model to examine how different forest thinning intensities might affect the long‐term production and abundance of live trees and deadwood. Our results suggest that there are long‐term habitat tradeoffs associated with different thinning intensities. Species that utilize large diameter live trees will benefit most from heavy thinning, whereas species that utilize large diameter deadwood will benefit most from light or no thinning. Because far more vertebrate species utilize large deadwood rather than large live trees, allowing riparian forests to naturally develop may result in the most rapid and sustained development of structural features important to most terrestrial and aquatic vertebrates.     

System dynamics model for analyzing effects of eco-design policy on packaging waste management system

EU's long-term objective is to become a recycling and resource effective society, where waste is utilized as a resource and waste generation is prevented. A system dynamics model was developed to analyze the policy mechanisms that promote packaging material efficiency in products through increased recycling rates. The model includes economic incentives such as packaging and landfill taxes combined with market mechanisms, behavioral aspects and ecological considerations in terms of material efficiency (the packaging material per product unit, recycled fraction in products). The paper presents the results of application of various policy instruments for increasing packaging material efficiency and recovery rate and reducing landfilled fraction. The results show that a packaging tax is an effective policy instrument for increasing the material efficiency. It ensures the decrease of the total consumption of materials and subsequent waste generation. The tax helps to counteract a rebound effect, which, as identified by the analysis, can be caused by reduced material costs due to eco-design. The model is applied to the case of Latvia. Yet, the elements and structure of the model developed are similar to waste management systems in many countries. By changing numeric values of certain parameters, the model can be applied to analyze policy mechanisms in other countries.     

植被混凝土在官地水电站的试验分析

本文主要对官地水电站高陡边坡植被混凝土前期绿化试验成果进行分析,以寻求在干湿季节明显、雨量集中、干旱季节漫长、温度高、蒸发量大等干热河谷气候特征条件下的最佳生境构筑方法,为官地水电站乃至雅砻江流域水电工程高陡边坡生态恢复提供技术依据。     

基于生物质能的芒属（Miscanthus）植物碳动态和收支研究进展

生物质能（Biomass energy）是最为广泛的可再生能源，其中多年生芒属C4植物（Miscanthus）由于具有巨大碳固定能力而成为潜力巨大的生物质能植物。中国是芒属植物芒草起源中心，但相对于欧洲国家应对能源危机和温室效应而采取的芒草研究与应用来说，仍处于起步阶段。我国长期以来传统的草地利用模式，决定了在南方草地的研究显著少于北方，近年来芒草在华南地区的运用研究集中于生态修复，对草本植物群落基于生态系统水平的 CO2气体交换能力的研究仍然相当缺乏，在二氧化碳浓度持续增长及全球变暖背景下，生物质能植物及其碳汇功能的相关研究尤显重要。我国南方近6700万hm2退化丘陵草坡急待恢复或处于恢复中，草坡地芒属植物符合生物质能植物标准，施肥少，害虫少，农药输入少，能够有效地利用光、水等自然资源。考虑到C4植物具有比C3植物更强的光合作用能力，高光能利用率C4芒属植物的碳固定能力及能源潜力值得重视，但缺乏科学的碳动态和碳收支评估。综述了国内外芒草生物量特征与生物质能潜力研究现状，重点论述芒属植物生态系统水平的碳动态和收支能力研究，探讨了系统水平更客观评估芒属碳源汇（Carbon sequestration）功能的方法，基于生物量过程的研究结果及华南地区草坡研究历史和现状，为草坡地生物质能的合理开发利用提出了相关对策，强调在我国南方开发和利用芒属植物资源具有重要能源价值和经济、环境效益。     

Two-Compartment Sorption of Phenanthrene on Eight Soils with Various Organic Carbon Contents

Sorption characteristics of phenanthrene (PHE) were studied on eight soils with organic carbon contents spanning over an order of magnitude using phase distribution relationships (PDRs) at 1 h, 48 h, and 720 h contact times. A new algebraic method was employed to describe the sorption characteristics at different time intervals (between 1 h and 48 h, and 1 h and 720 h). It was found that nonlinearity increased with increasing contact time and sorption that occurred in the subsequent time interval following the initial 1 h exhibited stronger isotherm nonlinearity. Sorption coefficients were positively correlated with the organic carbon contents of the soils. Detailed sorption dynamics were also examined on these soils. A two-compartment, first-order model was used to describe the sorption dynamics. The rate constants of the two compartments differed 18–170 times, suggesting the dissimilar sorption behaviors of the mathematically separated compartments. These two compartments were labeled fast and slow sorption compartment according to the rate constants. Calculation showed that the fast compartment accounted for over 80% of the overall sorption at the initial 1 h, while the slow compartment predominated the total sorption in the following 47 h. By combining the discussion of PDRs and sorption dynamics, the contributions of the two compartments to linear and nonlinear sorption were differentiated. The slow sorption compartment made a major contribution to nonlinear sorption and possibly to sequestration of organic pollutants by these soils.     

Lichen Conservation in Heavily Managed Boreal Forests

Lichens are an important component of the boreal forest, where they are long lived, tend to accumulate in older stands, and are a major food source for the threatened woodland caribou (Rangifer tarandus caribou). To be fully sustainable, silvicultural practices in the boreal forest must include the conservation of ecological integrity. Dominant forest management practices, however, have short‐term negative effects on lichen diversity, particularly the application of herbicides. To better understand the long‐term effects of forest management, we examined lichen regeneration in 35 mixed black spruce (Picea mariana) and jack pine (Pinus banksiana) forest stands across northern Ontario to determine recovery following logging and postharvest silvicultural practices. Our forest stands were 25–40 years old and had undergone 3 common sivilcultural treatments that included harvested and planted; harvested, planted, and treated with N‐[phosphonomethyl] glycine (glyphosate); and harvested, planted, and treated with 2,4‐dichlorophenoxyacetic acid (2,4‐D). Forest stands with herbicide treatments had lower lichen biomass and higher beta and gamma diversity than planted stands that were not treated chemically or control stands. In northwestern Ontario, planted stands that were not treated chemically had significantly greater (p < 0.05) alpha diversity than stands treated with herbicides or control stands. Our results show that common silvicultural practices do not emulate natural disturbances caused by wildfires in the boreal forest for the lichen community. We suggest a reduction in the amount of chemical application be considered in areas where lichen biomass is likely to be high and where the recovery of woodland caribou is an objective. Conservación de Líquenes en Bosques Boreales Manejados Intensivamente     

武宁县森林扰动及驱动因子分析

森林扰动是影响陆地生态系统的重要因子,也是影响全球碳循环的重要因素.以江西省武宁县为例,利用1986-2011年14景Landsat TM/ETM+遥感影像,通过扰动指数(disturbance index,DI)时间序列轨迹分析提取森林扰动信息,并引入经验正交函数(empirical orthogonal function,EOF)分解方法定量分析了森林扰动的时空变化规律,利用GIS深入分析了自然和社会驱动因子影响.结果表明,武宁县森林扰动在1986-1998年较强,扰动面积以1992年为最大,以地区性扰动为主;2000年以后则趋于平缓,扰动以砍伐和森林火灾为主;在空间上,扰动主要发生在近道路、低海拔、低坡度和近水地区,并受地形和交通的制约,城镇化逐渐成为该地区森林扰动的一个不可忽略的驱动因子.     

南水北调中线水源地不同植被类型坡地土壤水分特征研究

为了解不同植被类型土壤水资源的变化规律，选择南水北调中线水源区宁陕县寨沟区域典型植被针阔混交林、针叶林、板栗林、灌木林、荒坡草地和坡耕地为研究对象，通过样地调查与实验分析的方法对其土壤水分物理特征及有机质含量进行测定研究。结果表明，各种有林地的土壤容重、孔隙度和有机质等理化特征均优于荒坡和坡耕地；针阔混交林土壤含水量最高，蓄水能力明显好于其它植被类型；在垂直剖面上，各种植被类型坡地土壤含水量和饱和蓄水量随土壤深度的增加基本呈递减趋势，但有林地下降幅度较大，表层含水量明显高于荒坡与坡耕地表层。由此可见，在涵养水源方面，针阔混交林最好，针叶林、板栗林与灌木林次之，荒坡与坡耕地较差。