基于遥感的秸秆焚烧对江苏省气溶胶光学厚度时空分布的影响研究

为了解秸秆焚烧对大气气溶胶光学厚度(AOD)时空分布的影响,利用江苏省2010—2015年卫星监测数据和气象观测数据,计算了5—7月份江苏省的AOD信息,采用基于上下文的增强的火点遥感识别方法提取了6月江苏省的火点信息,分析了AOD与火点的时空变化特征,以期为开展大气环境监测与评价提供依据,为政府秸秆焚烧防控决策提供参考。结果表明:江苏省秸秆焚烧火点主要集中于6月,2010—2013年6月秸秆焚烧火点较多,2014年和2015年的火点数明显减少,且火点主要集中于长江以北地区,而长江以南地区较少;在没有秸秆焚烧的情况下(以5月和7月作为对照),江苏省AOD的空间分布表现为苏南最高,苏中其次,苏北最低;而受秸秆焚烧影响的6月,全省平均AOD值均大于5月和7月,其中江苏西部、苏北、苏南大部分地区AOD值明显增大,AOD高值区跟秸秆焚烧火点高发区分布总体一致;秸秆焚烧对苏南、苏中和苏北的AOD值影响存在一定差异,针对5—6月AOD进行差值计算,发现苏北AOD平均差值为0.19,苏南为0.22,苏中最小,仅为0.11,且苏中部分地区的AOD差值与火点的分布并非完全一致,这是由于6月苏中地区以东到东南风为主,且苏中平原秸秆焚烧排放的污染物更易扩散,导致秸秆焚烧对苏中地区AOD值的影响程度小于苏南和苏北,与火点的分布并不完全一致。可见,秸秆焚烧可对江苏省AOD的时空变化产生较明显的影响。     

基于承载力提升视角的村镇资源环境承载力评价研究：以北京大兴区采育镇为例

资源环境承载力评价是一系列国土空间规划的基础,是空间管控底线的重要组成部分。以北京大兴区采育镇作为案例区进行村镇尺度承载力评价探索,建立基于"驱动力-压力-状态-影响-响应"即DPSIR模型的承载力综合指标体系,分析镇内资源环境状况,得到各村承载力评价分级结果和基于承载力提升的空间规划方案评估结果。结果表明,采育镇内各村资源环境状态存在较大差异,这主要是由于各村人口密度、用地集约程度差异导致,也与各村用地结构、经济发展模式直接相关。该研究对未来小尺度承载力评价思路提出展望,同时为其他地区小尺度资源环境承载力评价提供参考。     

基于驱动力-压力-状态-响应模型的黄河流域甘肃段生态系统健康评价

基于驱动力-压力-状态-响应(DPSR)模型和熵权-变异系数综合赋权法对2010—2020年黄河流域甘肃段57个区(县)生态系统健康进行评价,分析各流域及各区(县)生态系统健康等级时空演变及障碍因子,有助于发现生态系统问题并提出合理的管理恢复策略。结果表明,2010—2020年黄河流域甘肃段生态系统健康状况整体显著提升,2013—2016年生态系统健康状况较差,2016年后健康状况得到明显改善。黄河干流流域1健康程度较高且健康值变化幅度最大,洮河流域健康状况改善较大,其余流域健康程度低且健康值涨幅较小。在整体准则层层面,黄河流域甘肃段驱动力、压力指数波动增长,状态与响应指数持续上升,表明2010—2020年黄河流域甘肃段生态系统健康状况得到稳定改善。人口增长、人均水资源量、建设用地比例和工业固体废物综合利用率等是影响黄河流域甘肃段生态系统健康等级变化的主要因素。优化土地利用、促进人口均衡分布、推动水资源均衡分配以及加强生态环境保护与修复是促进黄河流域甘肃段绿色发展与生态屏障建设的有效措施。     

江苏省陆域生态红线区域生态安全评价

2013年江苏省率先在全国划定生态红线,明确了最为关键的生态保护区域,确保了生态安全的底线。文章以江苏省划定的陆域生态红线区域为研究对象,基于PSR模型从压力、状态、响应三个方面构建了生态安全评价指标体系,利用组合赋权确定指标权重,结合GIS和遥感空间分析方法,对18个指标进行加权叠加分析,再利用综合指数法对生态红线区域的生态安全进行定量评价。结果显示:全省生态红线区域的生态安全综合指数为51.41分,其中状态层得分明显高于压力层和响应层,说明江苏省生态红线区域的自然环境状态保存较好;13个省辖市生态红线区域的生态安全综合指数整体上处于较高等级,76.88%的生态红线区域达到安全和较安全状态,反映出全省生态红线区域的生态安全水平较高,但其中处于安全状态的比例较低,仅5.81%;苏南地区和苏北地区由于经济发展水平差异,压力、状态和响应指数均有一定差别,苏南地区虽然经济发展水平高、区域开发指数大,但在响应层面做得更好,其生态红线区域的生态安全水平整体上高于苏北地区。     

北京城市空间扩展的生态环境响应及驱动力

城市土地利用变化及其生态环境响应是全球环境变化研究的重要组成部分,是可持续发展研究的核心问题。大都市作为人口和产业密集地区,城市土地利用变化剧烈,由此带来的生态环境问题更为显著。在新型城镇化建设背景下,研究大都市城市空间扩展及其生态环境响应,对提高大都市土地利用效能,转变经济增长方式和实现可持续发展具有重要指导意义。文章基于北京市遥感影像数据及相关社会经济数据,构建北京市空间扩展的生态环境响应评价指标体系和模型,对1995─2010年北京市空间扩展的生态环境响应进行了综合评价并分析其驱动力。研究认为:1995─2010年北京市各区县空间扩展的社会经济压力指数不断增大,首都功能核心区和城市功能拓展区各区县社会经济压力指数上升幅度最大,城市发展新区和生态涵养发展区各区县上升趋势较为平缓;除东城区和西城区外,各区县土地利用状态指数有所下降,降低幅度较大的区县有通州、顺义、大兴、平谷和昌平,较小的区县有朝阳、海淀、丰台、石景山和密云;除通州和大兴外,各区县空间扩展的生态环境响应指数均呈上升趋势,净变化量较大的区县主要位于首都功能核心区,生态涵养区和城市发展新区各区县净变化量较小;除通州、顺义、延庆和昌平外,各区县城市空间扩展的生态环境响应综合指数均有所提高,其中东城、西城、海淀和朝阳净变化量较大,顺义、平谷和怀柔净变化量较小,空间格局表现出"中心低、外围高、东南低、西北高"的特征;人口增长、城市化、经济发展、建设用地高速扩展、生态用地减少等对北京城市空间扩展的生态环境响应具有重要影响。     

基于MODIS数据的山东省秸秆焚烧与空气质量关系探析

秸秆焚烧释放的各类气体污染物和细微颗粒对空气质量影响极大,是大气污染的来源之一。MODIS传感器具有灵敏度高、时效性强和空间覆盖宽等优势,利用其数据对秸秆焚烧进行监测,可以快速获取大范围内秸秆焚烧火点的位置、数量和烈度等信息。采用基于MODIS发展的上下文算法提取火点,并收集研究区空气质量指数(air quality index,AQI),PM_(10)、PM_(2.5)、NO_2、SO_2、CO和O_3 6个空气质量分指数(individual air quality index,IAQI)数据以及相关气象数据,将山东省17个地市按照"是否沿海岸线分布"划分为沿海地区和内陆地区,对比分析秸秆焚烧对空气质量影响的差异性。将两类地区每日空气质量数据进行空间插值,对得到的区域所有栅格点的空气质量指数总和与该区域火点数进行时间序列上的相关性分析,进而分析秸秆焚烧造成的污染对环境空气质量的影响程度以及内陆、沿海地区空气污染的差异性。结果表明,火点数量与空气质量指数总和呈现正相关关系,且分别与AQI、PM_(2.5)、PM_(10)和O_3这4个指数呈极显著正相关关系(P0.01),火点增多产生的污染物使空气质量指数升高,导致空气质量下降。同时,沿海地区秸秆焚烧火点与空气质量指数的相关性强于内陆地区火点与空气质量指数的相关性,这表明大气扩散条件是研究秸秆焚烧环境效应的重要前提条件之一。     

江苏省农户秸秆还田的影响因素分析

农户秸秆还田不仅有利于土壤有机质的增加,实现耕地的可持续利用,而且在发挥我国农田土壤固碳潜力,积极应对气候变化方面具有重要意义.文章以江苏省农户调查数据为基础,建立Logistic模型,对影响农户秸秆还田的因素进行分析,以期为制定促进农户秸秆还田的政策提供科学依据.结果表明,不同地区农户对于秸秆还田的决策存在差异:在较为发达地区,秸秆还田与否,农户更多的是从秸秆处理的边际成本出发;而略欠发达地区,则主要是基于秸秆的利用效益.此外,技术因素也影响农户秸秆还田的行为决策.在制定促进秸秆还田技术应用的激励政策时,要充分考虑地区农业生产以及农户生产经营的基本特征及差异,因地制宜,有效地促进秸秆还田在各地区最大限度地被应用和推广.     

环长株潭城市生态系统健康评价

城市生态系统健康是区域可持续发展的基础.本文以环长株潭城市群作为研究对象,根据压力—状态—响应(PSR)模型,选取25个指标构建城市群城市生态系统健康评价指标体系,采用熵值法确定指标权重,以模糊综合评价法建立评价模型,对环长株潭城市生态系统健康进行评价.结果表明:总体来看,环长株潭城市生态系统健康水平处于"较健康"状态(0.236 2),处于一个良性发展阶段;城市群内部健康水平存在较大差异,不同地区的城市生态系统健康状况不同.长沙市和株洲市的隶属度为"健康",湘潭市和益阳市属于"较健康"状态,岳阳市和常德市属于"临界状态",衡阳市属于"不健康"状态,娄底市的隶属度为"病态".未来,环长株潭城市群要加强城市生态服务功能建设,缩小城市群内部差距,提升城市生态系统健康水平.     

京津冀及周边城市PM_(2.5)污染空间关联网络及季节演化研究

京津冀及周边城市是雾霾频发的重灾区,研究该地区城市的PM_(2.5)污染空间关联网络及其随季节演化情况,对于雾霾污染的协同治理具有重要的意义。选取2015年3月16日—2020年3月15日期间,京津冀及周边31个城市的日均PM_(2.5)浓度数据作为样本。首先,对不同城市PM_(2.5)浓度值的时序变化与空间分布进行了可视化展示;然后以城市为节点,城市日均PM_(2.5)浓度值皮尔逊相关系数为边,相关系数与城市最短距离的比值为权重构建京津冀及周边城市PM_(2.5)污染空间关联网络,并对网络的整体特征与季节演化情况进行了分析。结果表明,京津冀及周边城市PM_(2.5)污染空间关联网络图密度为0.473,平均度为14.194,网络图比较紧密;在区域内部,聚类系数较高城市大多位于中间城市带,PM_(2.5)污染也较为严重;石家庄与邢台的度值最高,分别为26与25,接近中心性与中介中心性也最高,控制其他城市PM_(2.5)污染传输的能力最强;在不同季节,城市PM_(2.5)指数相关性对比存在较大差异,采暖季平均聚类系数为0.82,非采暖季平均聚类系数为0.66,在采暖季城市PM_(2.5)污染空间关联更为紧密。因此,应当根据不同季节的气象条件,制定不同的PM_(2.5)污染防治政策,对于污染均比较严重的,位于中间城市带的城市,应重点监控,并积极推进京津冀及周边城市PM_(2.5)污染的一体化与协同治理。     

城市湖泊流域面源污染的源-汇效应研究--以武汉市东湖为例

随着城市点源污染控制不断完善,城市面源污染已成为危害中国城市水体的重要污染源.由城市土地利用变化引起的地表径流污染是导致湖泊水质恶化和富营养化的主要因素,加强面源污染的源-汇效应研究是控制、管理流域污染的重要途径之一.研究选取中国最大的城市湖泊武汉市东湖为研究对象,运用遥感和GIS技术,进行流域划分和地类解译,建立土地利用基础数据库,后对水质统计数据进行定量化处理,通过建立了地类——湖泊水质关系模型,科学地分析了用地与水质的关系,并对城市湖泊水质的季节动态、影响因素进行了初步探索.研究结果表明土地利用和气候变化对流域内湖泊水质的影响显著.其中,农田和建设用地是城市湖泊面源污染的主要来源,绿地和坑塘水面能够有效的截流、吸收污染物,起到保护湖泊水质的作用;受降水、温度等气候因子的影响,湖泊水质状态呈现季节性波动.研究选取东湖为研究对象,研究面源污染的源-汇效应,具有代表性,对于更好保护城市湖泊,合理利用湖泊资源提供了理论依据.     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Human Influence and Classical Biogeographic Predictors of Rare Species Occurrence

Biogeographic theory predicts that rare species occur more often in larger, less‐isolated habitat patches and suggests that patch size and connectivity are positive predictors of patch quality for conservation. However, in areas substantially modified by humans, rare species may be relegated to the most isolated patches. We used data from plant surveys of 81 meadow patches in the Georgia Basin of Canada and the United States to show that presence of threatened and endangered plants was positively predicted for patches that were isolated on small islands surrounded by ocean and for patches that were isolated by surrounding forest. Neither patch size nor connectivity were positive predictors of rare species occurrence. Thus, in our study area, human influence, presumably due to disturbance or introduction of competitive non‐native species, appears to have overwhelmed classical predictors of rare species distribution, such that greater patch isolation appeared to favor presence of rare species. We suggest conservation planners consider the potential advantages of protecting geographically isolated patches in human‐modified landscapes because such patches may represent the only habitats in which rare species are likely to persist. Influencia Humana y Predictores Biogeográficos Clásicos de la Ocurrencia de Especies Raras     

Seasonal dynamics of macro-algae in the South Lake of Tunis

The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe ecological imbalance, resulting in crises of anoxia and fish death. A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation system. The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities as a first step in the constitution of a database for further comparison.     

Patterns and biases of climate change threats in the IUCN Red List

International Union for Conservation of Nature (IUCN) Red List assessments rely on published data and expert inputs, and biases can be introduced where underlying definitions and concepts are ambiguous. Consideration of climate change threat is no exception, and recently numerous approaches to assessing the threat of climate change to species have been developed. We explored IUCN Red List assessments of amphibians and birds to determine whether species listed as threatened by climate change display distinct patterns in terms of habitat occupied and additional nonclimatic threats faced. We compared IUCN Red List data with a published data set of species’ biological and ecological traits believed to infer high vulnerability to climate change and determined whether distributions of climate change‐threatened species on the IUCN Red List concur with those of climate change‐threatened species identified with the trait‐based approach and whether species possessing these traits are more likely to have climate change listed as a threat on the IUCN Red List. Species in some ecosystems (e.g., grassland, shrubland) and subject to particular threats (e.g., invasive species) were more likely to have climate change as a listed threat. Geographical patterns of climate change‐threatened amphibians and birds on the IUCN Red List were incongruent with patterns of global species richness and patterns identified using trait‐based approaches. Certain traits were linked to increases or decreases in the likelihood of a species being threatened by climate change. Broad temperature tolerance of a species was consistently related to an increased likelihood of climate change threat, indicating counterintuitive relationships in IUCN assessments. To improve the robustness of species assessments of the vulnerability or extinction risk associated with climate change, we suggest IUCN adopt a more cohesive approach whereby specific traits highlighted by our results are considered in Red List assessments. To achieve this and to strengthen the climate change‐vulnerability assessments approach, it is necessary to identify and implement logical avenues for further research into traits that make species vulnerable to climate change (including population‐level threats).     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture