A counterfactual approach to measure the impact of wet grassland conservation on U.K. breeding bird populations

Wet grassland populations of wading birds in the United Kingdom have declined severely since 1990. To help mitigate these declines, the Royal Society for the Protection of Birds has restored and managed lowland wet grassland nature reserves to benefit these and other species. However, the impact of these reserves on bird population trends has not been evaluated experimentally due to a lack of control populations. We compared population trends from 1994 to 2018 among 5 bird species of conservation concern that breed on these nature reserves with counterfactual trends created from matched breeding bird survey observations. We compared reserve trends with 3 different counterfactuals based on different scenarios of how reserve populations could have developed in the absence of conservation. Effects of conservation interventions were positive for all 4 targeted wading bird species: Lapwing (Vanellus vanellus), Redshank (Tringa totanus), Curlew (Numenius arquata), and Snipe (Gallinago gallinago). There was no positive effect of conservation interventions on reserves for the passerine, Yellow Wagtail (Motacilla flava). Our approach using monitoring data to produce valid counterfactual controls is a broadly applicable method allowing large-scale evaluation of conservation impact.     

Reconciling multiple counterfactuals when evaluating biodiversity conservation impact in social-ecological systems

When evaluating the impact of a biodiversity conservation intervention, a counterfactual is typically needed. Counterfactuals are possible alternative system trajectories in the absence of an intervention. Comparing observed outcomes against the chosen counterfactual allows the impact (change attributable to the intervention) to be determined. Because counterfactuals by definition never occur, they must be estimated. Sometimes, there may be many plausible counterfactuals, including various drivers of biodiversity change and defined on a range of spatial or temporal scales. Here, we posit that, by definition, conservation interventions always take place in social-ecological systems (SES) (i.e., ecological systems integrated with human actors). Evaluating the impact of an intervention in an SES, therefore, means taking into account the counterfactuals assumed by different human actors. Use of different counterfactuals by different actors will give rise to perceived differences in the impacts of interventions, which may lead to disagreement about its success or the effectiveness of the underlying approach. Despite that there are biophysical biodiversity trends, it is often true that no single counterfactual is definitively the right one for conservation assessment, so multiple evaluations of intervention efficacy could be considered justifiable. Therefore, we propose calculating the sum of perceived differences, which captures the range of impact estimates associated with different actors in a given SES. The sum of perceived differences gives some indication of how closely actors in an SES agree on the impacts of an intervention. We applied the concept of perceived differences to a set of global, national, and regional case studies (e.g., global realization of Aichi Target 11 for marine protected areas, effect of biodiversity offsetting on vegetation condition in Australia, and influence of conservation measures on an endangered ungulate in Central Asia). We explored approaches for minimizing the sum, including a combination of negotiation and structured decision making, careful alignment of expectations on scope and measurement, and explicit recognition of any intractable differences between stakeholders.     

Understand the local and regional contributions on air pollution from the view of human health impacts

• PM_2.5-related deaths were estimated to be 227 thousand in BTH & surrounding regions. • Local emissions contribute more to PM_2.5-related deaths than PM_2.5 concentration. • Local controls are underestimated if only considering its impacts on concentrations. • Rural residents suffer larger impacts of regional transport than urban residents. • Reducing regional transport benefits in mitigating environmental inequality. The source-receptor matrix of PM_2.5 concentration from local and regional sources in the Beijing-Tianjin-Hebei (BTH) and surrounding provinces has been created in previous studies. However, because the spatial distribution of concentration does not necessarily match with that of the population, such concentration-based source-receptor matrix may not fully reflect the importance of pollutant control effectiveness in reducing the PM_2.5-related health impacts. To demonstrate that, we study the source-receptor matrix of the PM_2.5-related deaths instead, with inclusion of the spatial correlations between the concentrations and the population. The advanced source apportionment numerical model combined with the integrated exposure–response functions is used for BTH and surrounding regions in 2017. We observed that the relative contribution to PM_2.5-related deaths of local emissions was 0.75% to 20.77% larger than that of PM_2.5 concentrations. Such results address the importance of local emissions control for reducing health impacts of PM_2.5 particularly for local residents. Contribution of regional transport to PM_2.5-related deaths in rural area was 22% larger than that in urban area due to the spatial pattern of regional transport which was more related to the rural population. This resulted in an environmental inequality in the sense that people staying in rural area with access to less educational resources are subjected to higher impacts from regional transport as compared with their more resourceful and knowledgeable urban compatriots. An unexpected benefit from the multi-regional joint controls is suggested for its effectiveness in reducing the regional transport of PM_2.5 pollution thus mitigating the associated environmental inequality.     

鄱阳湖大型底栖动物群落结构的空间分布及影响因子研究

由于受人类活动干扰的加强以及受与长江干流之间"江湖关系"变化的影响,近年来鄱阳湖水生生态系统的状况及变化受到较多关注。对底栖动物群落结构的研究将有助于了解鄱阳湖生态系统结构现状及影响因子,对鄱阳湖保护对策的制定形成有效支撑。2016年7月,对鄱阳湖湖区(分别于鄱阳湖保护区和南矶山保护区)的底栖动物群落结构及相关环境因子进行了调查。调查共发现大型底栖动物27种,隶属于5门8纲,平均密度为48.40 ind.·m-2,其中主要以软体动物门为主;平均生物量为28.12 g·m-2,亦主要由软体动物门贡献。湖区主要优势种为河蚬(Corbicula fluminea)(优势度y=0.0655)、铜锈环棱螺(Bellamya aeruginosa)(y=0.0336)、霍甫水丝蚓(Limnodrilus hoffmeisteri)(y=0.0268)。底栖动物密度、生物量及多样性指数均呈现出鄱阳湖保护区高于南矶山保护区的格局,且二者在群落组成上有明显差异,鄱阳湖自然保护区主要以腹足纲和寡毛纲为主,南矶山自然保护区主要以瓣鳃纲和腹足纲为主。典范对应分析的结果显示,鄱阳湖保护区主要受到高水深、低浊度及高溶氧的影响;南矶山保护区各样点之间群落相似性较差,分别受不同因子的影响,这表明在各区域内部,局域微生境在局域群落结构的塑造上起主要作用,因此该区域内生态系统的保护应适当考虑空间尺度。     

Can floor-area-ratio incentive promote low impact development in a highly urbanized area?—A case study in Changzhou City,China

As an environmental friendly measure for surface runoff reduction, low impact development (LID) has been applied successfully in urban areas. However, due to high price of land and additional expense for LID construction in highly urbanized areas, the developers of real estate would not like to proceed LID exploitation. Floor area ratio (FAR) refers to “the ratio of a building’s total floor area to the size of the piece of land upon which it is built.” Increasing FAR indicates that the developers can construct higher buildings and earn more money. By means of awarding FAR, the developers may be willing to practice LID construction. In this study, a new residential district is selected as a case study to analyze the tradeoff between the runoff reduction goal achieving by LID practices and the incentive of awarding FAR to promote LID construction. The System for Urban Stormwater Treatment and Analysis IntegratioN (SUSTAIN) model is applied to simulate the runoff reduction under various LID designs and then derive the Pareto-optimal solutions to achieve urban runoff reduction goals based on cost efficiency. The results indicates that the maximum surface runoff reduction is 20.5%. Under the extremity scenarios, the government has options to award FAR of 0.028, 0.038 and 0.047 and the net benefits developers gain are 0 CNY, one million CNYand two million CNY, respectively. The results provide a LID construction guideline related to awarding FAR, which supports incentive policy making for promoting LID practices in the highly urbanized areas.

Open image in new window

     

新疆农用拖拉机排放清单及特征研究

分别应用参数本土化的NON-ROAD模型和生态环境部发布的《非道路移动源大气污染物排放清单编制技术指南》估算了新疆1993—2018年农业生产用拖拉机PM₁₀、PM_2.5、HC、NO_x和CO等污染物排放清单.同时,结合NON-ROAD模型特性、排放清单和区域现状,从定量和定性2个维度剖析了2种排放清单编制方法的适应性和污染物排放演变态势.最后,基于3种不同方法对污染物排放的潜在影响因素进行分析.结果表明：①基于参数本土化的NON-ROAD模型在建立特定区域排放清单方面具有一定参考价值.②1993—2018年新疆农用拖拉机污染物排放呈现出平稳上升、波动、快速增长、平稳、下降等不同态势,总体上,1993—2017年污染物排放增加25156.69 t,但在2018年出现较大幅度下降,同时单位功率排放也明显下降,表明近年来采取的强有力排放控制措施在抑制大气污染物排放方面的成效明显.③2006年之后大中型拖拉机年均排放总量占比为70.9%,小型拖拉机年均排放占比为29.1%,短期内随着时间的推移两者的差距将越来越大,揭示大中型拖拉机是污染物排放控制的关键.④对污染物排放影响因素的定量分析结果发现,农业经济发展水平对区域污染物排放总量变化起决定性作用.本研究在建立污染物排放清单、污染物排放影响因素定量分析及区域污染物排放治理政策制定方面有一定参考价值.     

塑料牛奶包装及处置方式生命周期环境影响研究

采用生命周期评价(LCA)法研究了塑料牛奶包装的全生命周期环境影响,并在处置阶段对不同处置方式的环境影响进行比较.通过现场和资料调研的方式,获得所有生命周期阶段能量物质的输入/输出和环境外排数据.结果表明:塑料牛奶包装生命周期阶段中环境影响比重最大的是原料获取阶段,占90%以上.其全生命周期环境影响主要集中在化石燃料、无机物对人体损害和气候变化3个方面,在致癌、酸化富营养化和生态毒性方面影响稍小.3种处置方式对环境影响由大到小依次为填埋>焚烧>再生,其中填埋和焚烧处置分别比塑料包装处置阶段前的环境影响增加16.1%和5.3%,再生可降低75.9%.     

地表夯击载荷作用下埋地管道力学分析

为研究地基强夯作业中夯击载荷对埋地管道力学性能的影响,基于有限元原理建立了夯锤-管道-围土耦合三维模型,分析了夯击过程中管道截面变形及所受冲击力变化规律,研究了管道壁厚、夯击速度、夯锤体积对管道应力、应变及变形的影响规律。结果表明:夯击载荷下的管道所受冲击力为脉冲型,且随时间推移逐渐降低为0,最大冲击力随管道壁厚、夯击速度、夯锤体积增大而增大;管道最大等效应力、高应力范围及最大等效塑性应变随壁厚增加而减小,但随夯击速度或夯锤体积增大而增大;随着夯击速度、夯锤体积增大,管道截面变形率（椭圆度或凹陷率）逐渐增大,但其随壁厚增加而减小。     

沉管隧道对接端深基坑止水墙水下爆破对周围环境的影响研究

基于爆破动态效应的现场监测数据,研究了襄阳汉江鱼梁州沉管隧道对接端深基坑止水墙水下爆破对邻近建(构)筑物和周围水域的不利影响.结果 表明:爆源附近方圆50 rn范围内属于爆破振动近场区、方圆50～150 m范围内属于爆破振动过渡区、方圆150 m范围外属于爆破振动远场区;爆破振动近场区内薄壁支护结构爆破振动速度呈现高峰...     

Home composting as an alternative treatment option for organic household waste in Denmark: An environmental assessment using life cycle assessment-modelling

An environmental assessment of the management of organic household waste (OHW) was performed from a life cycle perspective by means of the waste-life cycle assessment (LCA) model EASEWASTE. The focus was on home composting of OHW in Denmark and six different home composting units (with different input and different mixing frequencies) were modelled. In addition, incineration and landfilling was modelled as alternatives to home composting. The most important processes contributing to the environmental impact of home composting were identified as greenhouse gas (GHG) emissions (load) and the avoided emissions in relation to the substitution of fertiliser and peat when compost was used in hobby gardening (saving). The replacement of fertiliser and peat was also identified as one of the most sensible parameters, which could potentially have a significant environmental benefit. Many of the impact categories (especially human toxicity via water (HTw) and soil (HTs)) were affected by the heavy metal contents of the incoming OHW. The concentrations of heavy metals in the compost were below the threshold values for compost used on land and were thus not considered to constitute a problem. The GHG emissions were, on the other hand, dependent on the management of the composting units. The frequently mixed composting units had the highest GHG emissions. The environmental profiles of the home composting scenarios were in the order of −2 to 16 milli person equivalents (mPE) Mg⁻¹ wet waste (ww) for the non-toxic categories and −0.9 to 28 mPE Mg⁻¹ ww for the toxic categories. Home composting performed better than or as good as incineration and landfilling in several of the potential impact categories. One exception was the global warming (GW) category, in which incineration performed better due to the substitution of heat and electricity based on fossil fuels.