甘南地区二氧化碳施肥效应对生态系统的影响

陆地生态系统是全球第二大碳库,其碳收支一直是气候变化研究的热点领域,而研究二氧化碳（CO₂）施肥效应又是全球变化碳循环领域较为关注的前沿部分。CO₂与生态系统关系复杂,当前仍无法厘清CO₂对陆地生态系统碳循环的影响作用。基于太阳辐射数据、气温数据及归一化植被指数数据等,利用光能利用率遥感模型,模拟2019年甘南地区的碳循环,选取三个指标,即GPP （陆地生态系统总初级生产力）、NPP （净初级生产力）和NEP （净生态系统生产力）来分析甘南地区植被固碳的时空变化特征及CO₂施肥效应。结果表明：（1）甘南地区2019年植被固碳总量约为2611 tC。甘南地区生态系统GPP、NPP和NEP季节性特征明显,其值均在夏季达到最高;而在空间上,GPP、NPP表现为东高西低的特征,NEP呈现出北高南低的分布特征。（2） CO₂对GPP、NPP存在正向的施肥效应,分别增加了14.4%和14.3%;而对NEP具有负向反馈效应,使其减少了0.3%,并且CO₂对NEP的影响整体也表现为北高南低的特征。研究揭示出：虽然CO₂在提升GPP和NPP时,正向的施肥效应明显,但是对甘南地区的NEP,即固碳量来说,CO₂的影响却很有限。因此在研究CO₂施肥效应时不应一概而论,生态地理环境对其的影响不可忽视。研究可以为揭示陆地生态系统碳循环的动态机制提供一定的理论依据。     

Quantifying the recent expansion of native invasive rush species in a UK upland environment

Rushes, such as soft rush (Juncus effusus L.), hard rush (Juncus inflexus L.), and compact rush (Juncus conglomeratus L.) have become problem species within upland grasslands across the United Kingdom and the coastal grasslands of western Norway. Indeed, being largely unpalatable to livestock and having a vigorous reproductive ecology means that they can rapidly come to dominate swards. However, rush dominance results in a reduction in grassland biodiversity and farm productivity. Anecdotal evidence from the United Kingdom suggests that rush cover within marginal upland grasslands has increased considerably in recent decades. Yet, there is currently no published evidence to support this observation. Here, we use recent and historical Google Earth imagery to measure changes in rush frequency over a 13-year period within four survey years: 2005, 2009, 2015, and 2018. During each survey year, we quantified rush presence or absence using a series of quadrats located within 300 upland grassland plots in the West Pennine Moors, United Kingdom. Data were analysed in two stages, first, by calculating mean rush frequencies per sample year using all the available plot-year combinations (the full dataset), and second by examining differences in rush frequency using only the plots for which rush frequency data were available in every sample year (the continuous dataset). The full dataset indicated that rush frequency has increased by 82% between 2005 and 2018. Similarly, the continuous dataset suggested that rush frequency has increased by 174% over the same period, with the increases in frequency being statistically significant (p < .05) between 2005–2018 and 2009–2018. We discuss the potential drivers of rush expansion in the West Pennine Moors, the ecological and agronomic implications of grassland rush infestations, and priorities for future research.     

Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool

GeoCAT is an open source, browser based tool that performs rapid geospatial analysis to ease the process of Red Listing taxa. Developed to utilise spatially referenced primary occurrence data, the analysis focuses on two aspects of the geographic range of a taxon: the extent of occurrence (EOO) and the area of occupancy (AOO). These metrics form part of the IUCN Red List categories and criteria and have often proved challenging to obtain in an accurate, consistent and repeatable way. Within a familiar Google Maps environment, GeoCAT users can quickly and easily combine data from multiple sources such as GBIF, Flickr and Scratchpads as well as user generated occurrence data. Analysis is done with the click of a button and is visualised instantly, providing an indication of the Red List threat rating, subject to meeting the full requirements of the criteria. Outputs including the results, data and parameters used for analysis are stored in a GeoCAT file that can be easily reloaded or shared with collaborators. GeoCAT is a first step toward automating the data handling process of Red List assessing and provides a valuable hub from which further developments and enhancements can be spawned.     

Richer histories for more relevant policies: 42 years of tree cover loss and gain in Southeast Sulawesi,Indonesia

Understandings of contemporary forest cover loss are critical for policy but have come at the expense of long‐term, multidirectional analyses of land cover change. This is a critical gap given (i) profound reconfigurations in land use and land control over the past several decades and (ii) evidence of widespread ‘woodland resurgence’ throughout the tropics. In this study, we argue that recent advancements within the field of land change science provide new opportunities to address this gap. In turn, we suggest that multidecadal and multidirectional analyses of land cover change can facilitate richer social analyses of land cover change and more relevant conservation policies and practice. Our argument is grounded in a case study from Southeast Sulawesi, Indonesia. Using a novel analytical platform, Google Earth Engine, and open access to high‐quality Landsat data, we map land cover change in Southeast Sulawesi, Indonesia, from 1972 to 2014. We find that tree cover loss constitutes the single largest net change over the period 1972–2014 but that gross rates of tree cover gain were three times higher than gross loss rates from 1972 to 1995 and equivalent to loss rates from 1995 to 2014. We suggest the smallholder tree crop economy likely produced both forest loss and Imperata grassland restoration in this region. This case points to the need to expand rather than collapse the baselines used to study carbon and biodiversity change in tropical regions. It also demonstrates the possible utility of applying such methods to other regions.     

江苏重要生态功能区质量演变及红线管控效应

生态保护红线区作为重要生态功能区,对国家生态安全起到了基础保障作用。如何准确有效地评估生态保护红线区生态质量演变以及生态保护红线的作用,对“红线”政策的进一步完善和区域可持续发展具有重要意义。基于Google Earth Engine平台,利用Landsat 5、8长时序遥感影像构建出江苏全域1985—2021年遥感生态指数RSEI,分析了生态保护红线区1985年以来的生态质量演变情况,评估了2013年以来实施的生态保护红线政策在生态保护方面的效用。结果表明：(1)针对江苏全域构建的RSEI模型PC1平均贡献率高于70%,适用于江苏全域及生态保护红线区的生态质量演变分析。1985—2021年RSEI提升的面积占江苏总面积的58.2%,红线区平均RSEI值在0.52—0.63间变化,整体呈现波动上升的趋势;(2)江苏生态保护红线区整体RSEI均值突变年份在2003年,各市红线区RSEI均值突变年份大多集中在1995—2005年间,1990年代苏南和苏中部分城市出现由好向差的突变,2000年代苏北城市出现由差向好的突变;(3)生态保护红线具有屏蔽效应,有效阻挡了建筑用地等不透水面和裸土向保...     

基于Google Earth Engine的长三角城市群生态环境变化与城市化特征分析

作为城市发展的最高空间组织形式，城市群在高速城市化进程中将不可避免的对地区生态环境产生胁迫影响。如何平衡生态环境和城市化发展已经成为了值得关注的问题。以长三角城市群为例，基于Google Earth Engine云平台，通过整合日间光学遥感和夜间灯光遥感数据对生态环境状况、城市化强度以及二者在发展过程中的耦合协调特征开展了长时间序列的对比分析。结果表明：1）长三角城市群在过去近20年间的遥感生态环境指数（Remote Sensing-based Ecological Index，RSEI）稳定上升，生态环境呈现出好转的态势，但地区间的差异依旧显著；2）综合灯光指数（Comprehensive Nighttime Light Index，CNLI）能够较为准确的刻画城市群的城市化水平，研究期间内长三角城市群形成了"层次分明"、"由东向西"逐步推进的多层次的城市化格局，其中高强度城市化城市集中在上海市及其周边的无锡、苏州和嘉兴，低强度城市化城市则分布在城市群西部；3）基于CNLI和RSEI指数构建的耦合协调距离模型能够有效的识别出城市群内部城市化与生态环境的耦合协调程度，并根据象限特征将城市群城市划分为良好协调类型、初级协调类型、城市化滞后型和生态环境滞后型城市。     

Does searching online for vaccination information affect vaccination coverage? Evidence from Sub-Saharan African countries

The Internet is reshaping the way people access health information. Over the past decades, an increasing number of people have been using the Internet to access vaccine-related information. Many studies suggest that the Internet can help improve people’s understanding of health issues but at the same time facilitate the rapid spread of misinformation. This study explores the impact that searching the Internet for immunization information has on vaccination coverage. Using Google trends data, we found that access to online vaccination information has impacted vaccine uptake from 2004 to 2017, in Sub-Saharan African countries. The results indicate an overall positive impact on vaccine uptake. We also found that the effects are heterogeneous among vaccines. The effect is statistically significant for the vaccine related to high-risk disease, but not significant for the controversial vaccine and the vaccine related to low-risk disease.     

Google trends data need validation: Comment on Durmuşoğlu (2017)

In a recent article, Durmu?o?lu (2017) proposes the use of Google Trends data to study public understanding of environmental risks and claims such data do not require validation. Here, I show this assumption is false and that some of the terms used by the author fail a validity assessment, ultimately affecting the overall value of the study. Authors and reviewers of studies aiming to take advantage of digital data should adopt an enthusiastic but critical approach, particularly with regards to key assumptions and defining methodological aspects.     

基于谷歌地球引警和改进型遥感生态指数的西安市生态环境质量动态监测

近年来,在经济全球化的背景下,西安市经济迅速增长,生态环境问题日益突出,快速全面地定量监测生态环境质量的时空变化,对指导生态环境保护具有重要意义。基于谷歌地球引警(GEE)平台,筛选2000、2004、2010、2015、2020年及其前后各一年的四季Landsat影像,利用主成分分析基于绿度(NDVI)、热度(LST)、干度(NDSI)、湿度(Wet)和气溶胶光学厚度(AOD)构建改进型遥感生态指数(ARSEI),实现西安市2000—2020年生态环境质量的动态监测,并运用莫兰指数(Moran′s I)探讨西安市生态环境质量的空间自相关。以主成分效果最好的夏季为例,结果表明：(1)构建的ARSEI将大气污染因素考虑在内,第1主成分(PC1)贡献度在83%以上,能较好地集中各指标特征,有助于更加全面地评价研究区生态环境质量;(2)西安市2000—2020年平均ARSEI分别为0.565、0.521、0.572、0.644、0.695,生态环境质量总体呈现先退化后转好的趋势。20年来,生态环境质量较差和极差等级的面积减少了1339.08 km²,主要分布在秦岭以北地...