2022冬奥背景下京北地区绿色发展战略研究初探

随着经济的快速发展,人们逐步意识到依靠不断增加生产要素投入的粗放型经济发展模式已难以为继,绿色发展遂成为全球共识。作为北京生态涵养区的京北地区,在冬奥会和京津冀协同发展的机遇下,制定绿色发展战略,保护生态涵养功能,加快产业转型升级,促进经济、社会、环境协调发展,具有十分重要的意义。本文归纳总结了国际上绿色发展的借鉴经验,通过对京北地区经济发展现状和绿色发展SWOT的分析,设计出京北地区绿色发展基本框架,包括一个目标、三大战略、五项重点任务和五项保障措施。通过落实经济系统、社会系统和环境系统的三大战略措施,突破资源环境约束和共享绿色经济,最终实现京北地区的绿色跨越式发展。     

Concentrations of carbon monoxide and methane at two heights above a grass field and their deposition onto the field

To investigate whether wind is a significant driving force in the diffusion of CO and CH₄ from the atmosphere into soil, we measured the concentrations of these two gases at two heights above a temperate grass field in Japan and estimated their deposition velocities using micrometeorological techniques. The concentrations were inversely correlated with wind speed, indicating that the local concentrations were influenced by ground sources. The CO and CH₄ concentrations at 0.33 m were usually lower than those at 1.3 m. Although nocturnal data are suspected to be non-stationary, by selecting several periods when the changes of the concentrations were small but larger than analytical precision, we obtained a CO velocity of 2.9 and 3.9×10⁻² cms⁻¹, agreeing with a CO deposition velocity, 3.4×10⁻² cms⁻¹, obtained by applying a method using CO₂ as a tracer. The CH₄ influx obtained by the method using CO₂ as a tracer was 13 ngm⁻² s⁻¹. The ranges of the CO deposition velocity and CH₄ influx were similar to those obtained in previous studies in grassfields and in a nearby arable field using a closed-chamber technique. This shows that light winds do not greatly accelerate CO and CH₄ uptake by soil.     

Heterogeneous preferences for recreation-oriented management in commercial forests: the role of citizens’ socioeconomic characteristics and recreational profiles

The management of forests for multiple benefits, such as recreational services alongside timber production, can greatly benefit from the knowledge of public preferences for management-related forest attributes. This paper investigates citizens’ recreational use and preferences for recreation-oriented management in the case of state-owned commercial forests in Finland using data from a choice experiment study. We focus on attributes related to the typical management practices applied to enhance recreation: scenic buffer zones along waters, game bird habitats, and the quality of scenery along hiking trails. Recreational use and its frequency were found to be related to citizens’ background and specific outdoor activities. The scenic buffer zones were the most important attribute to the citizens. While the recreation-enhancing practices were generally valued, respondent segments with distinct preferences were found. Preference heterogeneity was related to citizens’ socioeconomic characteristics and recreational profiles.     

Spatial Economic–Hydroecological Modelling and Evaluation of Land Use Impacts in the Vecht Wetlands Area

Wetlands provide many important goods and services to human societies, and generate nonuse values as well. Wetlands are also very sensitive ecosystems that are subject to much stress from human activities. Reducing the stress on wetlands requires a spatial matching between physical planning, hydrological and ecological processes, and economic activities. Spatially integrated modelling and evaluation can support this. The present study has developed a triple layer model that integrates information and concepts from social and natural sciences to address the analysis and evaluation of land-use scenarios for a wetlands area in the Netherlands, the Vecht area. This is the floodplain of river Vecht, located in the centre of the Netherlands. The study has resulted in a set of linked spatial hydrological, ecological and economic models, formulated at the level of grids and polders. The main activities incorporated in the system of models are housing, infrastructure, agriculture, recreation and nature conservation. The formulation of alternative development scenarios is dominated by land use and land cover options that are consistent with the stimulation of agriculture, nature or recreation. Two aggregate performance indicators have been constructed from model output, namely net present value of changes and environmental quality. The spatial characteristics of these indicators are retained in a spatial evaluation that ranks scenarios.     

Cost–benefit analysis of beach-cast harvest: Closing land-marine nutrient loops in the Baltic Sea region

Harvesting beach-cast can help mitigate marine eutrophication by closing land-marine nutrient loops and provide a blue biomass raw material for the bioeconomy. Cost–benefit analysis was applied to harvest activities during 2009–2018 on the island of Gotland in the Baltic Sea, highlighting benefits such as nutrient removal from the marine system and improved recreational opportunities as well as costs of using inputs necessary for harvest. The results indicate that the activities entailed a net gain to society, lending substance to continued funding for harvests on Gotland and assessments of upscaling of harvest activities to other areas in Sweden and elsewhere. The lessons learnt from the considerable harvest experience on Gotland should be utilized for developing concrete guidelines for carrying out sustainable harvest practice, paying due attention to local conditions but also to what can be generalized to a wider national and international context.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01641-8.     

Effect of potential HONO sources on peroxyacetyl nitrate (PAN) formation in eastern China in winter

As an important secondary photochemical pollutant, peroxyacetyl nitrate (PAN) has been studied over decades, yet its simulations usually underestimate the corresponding observations, especially in polluted areas. Recent observations in north China found unusually high concentrations of PAN during wintertime heavy haze events, but the current model still cannot reproduce the observations, and researchers speculated that nitrous acid (HONO) played a key role in PAN formation. For the first time we systematically assessed the impact of potential HONO sources on PAN formation mechanisms in eastern China using the Weather Research and Forecasting/Chemistry (WRF-Chem) model in February of 2017. The results showed that the potential HONO sources significantly improved the PAN simulations, remarkably accelerated the RO_x (sum of hydroxyl, hydroperoxyl, and organic peroxy radicals) cycles, and resulted in 80%–150% enhancements of PAN near the ground in the coastal areas of eastern China and 10%–50% enhancements in the areas around 35–40°N within 3 km during a heavy haze period. The direct precursors of PAN were aldehyde and methylglyoxal, and the primary precursors of PAN were alkenes with C > 3, xylenes, propene and toluene. The above results suggest that the potential HONO sources should be considered in regional and global chemical transport models when conducting PAN studies.     

放牧对张家界索溪峪景区土壤微生物区系及活度的影响

为了探明旅游对张家界景区土壤微生物的影响,进行了放牧对土壤微生物区系及活度的影响研究。结果表明:放牧显著影响了0～5cm土壤的细菌、放线菌、真菌总数,活动区的细菌和真菌等主要有机质分解菌明显低于缓冲区和背景区,而背景区的放线菌明显高于缓冲区和活动区。在5～15、15～25cm土壤层中,细菌和放线菌总数没有受到放牧的影响,但背景区和缓冲区的真菌总数均显著高于活动区,活动区的细菌在5～15cm土壤中最多,而放线菌和真菌数量均表现为随土壤深度增加而减少的趋势。在缓冲区和背景区土壤中,3类微生物的数量均随土壤深度增加而减少。放牧也对表层土壤中的好气性纤维素分解菌、嫌气性纤维素分解菌、好气性固氮菌、硝化细菌以及反硝化细菌等微生物生理群造成了显著影响。土壤微生物活度随土壤深度增加而降低。在0～5和5～15cm²个土壤层中,缓冲区和活动区的微生物活度均明显高于背景区,而缓冲区的微生物活度与活动区的微生物活度没有显著性差异,微生物活度表现为活动区>缓冲区>背景区;在15～25cm土壤层中,活动区与缓冲区的微生物活度没有显著性差异,缓冲区与背景区的微生物活度没有显著性差异,但活动区的微生物活度明显高于背景区的微生物活度。     

改进多目的地旅行公共费用分成模型及其在若尔盖县游憩价值评估中的应用

多目的地环程旅行问题是应用旅行费用法(TCM)进行游憩价值评估的难点和热点,客观准确地对多目的地旅行公共费用进行分成,确定各目的地的费用权重成为游憩价值评估的关键性问题。因此,本文引入旅行公共费用和目的地直接费用的概念,改进多目的地旅行公共费用分成计算模型,将待评估目的地直接费用与多目的地总直接费用的比值作为待评估目的地在旅行公共费用中的分成权重。该计算模型尝试根据调查游客自身的消费特点进行旅行公共费用分成,避免主观假设的影响,旨在使费用分成更加客观、科学。对若尔盖县游憩价值的评估结果为:2017年若尔盖县游憩价值为31.09亿元,人均游憩价值1538元;其中旅行费用25.06亿元,人均旅行费用1240元;消费者剩余6.03亿元,人均消费者剩余298元。通过改进多目的地旅行费用分成模型,可推动游憩价值评估方法的发展和完善。研究结果可为若尔盖县生态旅游产业发展规划提供科学指导。     

中国典型冰雪旅游地开发模式及优化路径

北京冬奥会的筹办为中国冰雪旅游发展带来巨大契机,促进了冰雪旅游地的蓬勃发展。基于冰雪旅游地系统理论,构建了冰雪旅游地发展水平评价指标体系,并利用层次分析法、熵权法及加权Topsis法,对崇礼、亚布力、神农架、西岭雪山四个中国典型冰雪旅游地发展水平进行了测度。结果表明：崇礼冰雪旅游发展水平最高,亚布力次之,神农架及西岭雪山仍有待提升。基于此,提炼出四种典型冰雪旅游地开发模式,包括资源主导内驱模式、市场主导外驱模式、资源市场双核共驱模式以及资源市场政策综合齐驱模式。同时,从冰雪旅游地系统视角,提出了中国冰雪旅游地开发优化路径。研究有助于丰富冰雪旅游开发相关理论,为中国冰雪旅游地高质量发展提供智力支撑和案例借鉴。     

Colonies of Cliff Swallows on Highway Bridges: A Source of Escherichia coli in Surface Waters1

Sejkora, Patrick, Mary Jo Kirisits, and Michael Barrett, 2011. Colonies of Cliff Swallows on Highway Bridges: A Source of Escherichia coli in Surface Waters. Journal of the American Water Resources Association (JAWRA) 47(6):1275–1284. DOI: 10.1111/j.1752‐1688.2011.00566.x Abstract: Animals, such as birds, are a source of fecal indicator bacteria and pathogens in the environment. Our objective was to determine whether a colony of cliff swallows nesting underneath a bridge would yield a measurable increase in fecal indicator bacteria (specifically Escherichia coli) in the underlying creek. When the swallows were absent, dry‐weather concentrations of E. coli upstream and downstream of the bridge (in Austin, Texas) were below the Texas contact recreation criteria. When the swallows were present, dry‐weather geometric‐mean E. coli concentrations increased significantly from upstream (43 most probable number [MPN]/100 ml) to downstream (106 MPN/100 ml) of the bridge. One exceedance and one near‐exceedance of the Texas single‐sample contact recreation criterion were observed during the swallows’ nesting phase. When the swallows were present, the downstream E. coli geometric‐mean concentration in storm events (875 MPN/100 ml) was significantly higher than the upstream concentration (356 MPN/100 ml), suggesting that runoff flushes swallow feces from the ground into the creek. Although the loading of E. coli from cliff swallows nesting under bridges can be significant (e.g., dry‐weather loading of 3.1 × 10⁸ MPN/day/nest), the zoonotic potential of the cliff swallow must be examined to determine the risk to human health from contact recreation in waters contaminated with cliff swallow feces.