全球及区域尺度土地覆盖土地利用遥感研究的现状和展望

９０年代以来,利用遥感进行大面积土地覆盖土地利用的研究取得了一系列重要进展。已建立的全球及区域土地覆盖土地利用数据库正在得到广泛的应用,取得明显的社会效益和经济效益。土地覆盖土地利用及其变化的研究成果也被应用于有关全球环境变化国际公约的执行监督。利用遥感进行大面积土地详查已经逐步摆脱单一制图的传统概念,正在向建立以应用为目的且便于用户使用的综合信息数据库的方向迈进。此外,如何对大面积土地覆盖数据库进行精度评价已引起广泛重视,出现了一些新的理论和研究方法。进入２１世纪,全球和区域土地覆盖土地利用的遥感研究将进一步深化     

三峡库区水资源污染问题及对策研究

三峡工程是举世闻名、倍受世人关注的跨世纪工程。2008年三峡大坝蓄水,江水流速将大大减缓,长江的自净能力下降,污染物的环境容量急剧下降,库区水资源的污染程度将不断增加。三峡工程的生命力不仅仅决定于三峡工程本身的工程质量,最终决定于三峡库区的生态环境质量。库区的环境质量越高,三峡工程的使用寿命就越长,库区的环境质量越差,三峡工程的使用寿命就越短。三峡库区水资源污染问题是三峡工程寿命周期的致命因素。应高度重视三峡库区水资源污染问题,尽快制定三峡库区水资源保护制度,加大库区水资源保护资金的投入,完善库区水污染治理机制。     

基于静稳累积污染的石嘴山市PM2.5局地源解析

为探究静稳条件下PM_2.5局地源累积特征,在石嘴山市的4个不同功能区站点采集PM_2.5样品,并测量其水溶性离子、无机元素和含碳组分浓度,利用后向轨迹模型判断潜在源区,分析了静稳期和非静稳期PM_2.5组分浓度差异,并采用PMF模型判断静稳期局地源排放特征。结果表明:①观测期间有2次重污染过程是由局地污染物累积引起的;②沙尘源为主要的外来源,冬季非静稳期存在Si、Ca、Fe浓度大幅上升现象(浓度达到15.11、27.03、18.89 μg/m³),水溶性离子易在静稳条件下累积,受采暖影响,NO₃^-、SO₄^2-在冬季有更大的贡献,NO₃^-/SO₄^2-的值表明秋季机动车源对PM_2.5的贡献较大,冬季燃煤源对PM_2.5的贡献较大,OC/EC的值表明局地排放二次有机气溶胶转化效率不强;③静稳条件下受局地源影响,太沙站点S、Mn、SO₄^2-、EC等与工业排放相关的组分浓度最高,沟口站点受机动车源的影响,NO₃^-浓度最高(22.66 μg/m³),崇岗站点受煤炭加工排放影响,OC浓度远高于其他站点;④ PMF模型解析结果显示,石嘴山市局地源中工业源(47.4%)贡献最大,其次为机动车与扬尘混合源(29.3%)、二次源(15.1%)。     

长江中下游地区丰水期河、湖水氢氧同位素组成特征

稳定同位素技术在示踪水体的来源、演化及不同水体间相互转化关系、污染源已被广泛地应用.基于2018年7月对长江中下游地区长江干流河水和湖水同位素样品收集,本文分析了长江中下游地区丰水期河水和湖水中δ¹⁸O和δ²H组成特征,在此基础上进一步揭示了其空间上演化特征及其影响因素.结果表明长江干流δ¹⁸O和δ²H值自三峡库区向下游地区呈逐渐增大的变化趋势,这与降水同位素变化密切相关.在三峡库区段与宜昌-城陵矶段河水δ¹⁸O和δ²H值无显著差异,而河水d-excess值波动范围较小.在洞庭湖-江汉和华阳-鄱阳湖湖泊群中湖水δ¹⁸O和δ²H值要贫于太湖-三角洲湖泊群,且太湖-三角洲湖泊群湖水中d-excess值为负值,这主要是太湖-三角洲地区受同位素较为富集的降水和强烈的蒸发作用的影响.在淀山湖和大通湖同位素值最大,洞庭湖和鄱阳湖同位素值偏小,这主要是由于长江与鄱阳湖、洞庭湖直接相通,两湖的水情直接受制于长江影响,水位较高,鄱...     

The immediate costs and long-term benefits of assisted gene flow in large populations

With the genetic health of many plant and animal populations deteriorating due to climate change outpacing adaptation, interventions, such as assisted gene flow (AGF), may provide genetic variation necessary for populations to adapt to climate change. We ran genetic simulations to mimic different AGF scenarios in large populations and measured their outcomes on population-level fitness to determine circumstances in which it is worthwhile to perform AGF. In the absence of inbreeding depression, AGF was beneficial within a few generations only when introduced genotypes had much higher fitness than local individuals and traits affecting fitness were controlled by a few genes of large effect. AGF was harmful over short periods (e.g., first ∼10–20 generations) if there was strong outbreeding depression or introduced deleterious genetic variation. When the adaptive trait was controlled by many loci of small effect, the benefits of AGF took over 10 generations to realize—potentially too long for most climate-related management scenarios. The genomic integrity of the recipient population typically remained intact following AGF; the amount of genetic material from the donor population usually constituted no more of the recipient population's genome than the fraction of the population introduced. Significant genomic turnover (e.g., >50% replacement) only occurred when the selective advantage of the adaptive trait and translocation fraction were extremely high. Our results will be useful when adaptive management is used to maintain the genetic health and productivity of large populations under climate change.     

2015—2020年广东臭氧污染特征、污染天气分型及局地气象要素影响

利用2015—2020年广东省102个国控大气环境监测站臭氧(O₃)监测数据、广东省21个地市国家基本气象站地面气象观测数据和欧洲中期天气预报中心(ECMWF)第五代大气再分析全球气候数据(ERA5再分析资料)，研究了2015—2020年广东O₃污染特征、污染天气分型及局地气象要素影响.结果表明：2017—2019年广东O₃污染较严重，4—5月O₃浓度逐步上升，6月出现一定下降后7月开始持续上升，峰值出现在9—10月；珠三角O₃超标率明显高于全省其他地区，粤东O₃超标率低于全省平均水平，但浓度平均值高于全省其他地区.基于自组织映射(SOM)方法，将2015—2020年逐日海平面气压和10 m水平风进行分型得到12类环流型，按污染程度分为“污染天气型”、“轻污染天气型”和“清洁天气型”.其中“污染天气型”有台风外围叠加副高型、冷锋前部型、热带系统降水前静稳型、高压底前部型4类.12类天气型所对应的O₃浓度与日照时数、最高气温呈显著正相关...     

Making a case for the consideration of trust,justice, and power in conservation relationships

In conservation, trust and justice are increasingly recognized as both intrinsically valuable and critical for successful socioecological outcomes. However, the interdependence between these concepts has not been explored. The conservation trust literature provides examples of efforts to build trust between conservationists and local actors; yet, these interventions are often conceived to incentivize local cooperation within dominant paradigms. We argue that when trust building is promoted as a technical fix that does not plan in advance to address power asymmetries in conservation practice, inequities may inadvertently be re-embedded. Therefore, we conceptualized a framework that joins trust, justice, and power so that critical analyses of conservation partnerships can be more effectively undertaken. We drew on environmental justice theory to better calibrate the trust literature for the historical-political settings of conservation, especially in the Global South. Justice and trust share strong theoretical links where perceptions of justice shape a willingness to trust, and, equally, trust is a precondition for justice to be perceived. Different forms of trust connect to varied domains of justice and power in different ways, which mediates the outcomes of interventions. We applied our framework to case studies to explore how these interdependences play out in practice. Failure of agencies to attend to issues of maldistribution, misrecognition of cultural values and knowledge, and exclusion from participation strongly compromised trust. Moreover, the ways in which nature-dependent communities and marginalized conservation workers are trusted, or the conditions under which they give trust, can lead to partnerships being perceived as just or unjust. Focusing on trust and justice can help identify power dynamics so they can be addressed more readily and create space for alternative understandings of partnerships.