城市空气真菌群落多样性研究概况

对城市空气真菌的一般研究方法、分布特征、影响因素、危害等方面进行了综述,并对空气真菌的研究前景进行了展望。空气真菌生长的影响因素较多,其分布特征与当地的气候条件和生态环境密切相关,群落特征和分布状况具有明显的时间性和地域性。在条件适宜时,空气真菌孢子浓度的增加,对人类健康和生活环境造成严重的危害。     

A review of influences of land use and land cover change on ecosystems

随着人口的增长和人类社会的发展, 土地利用与土地覆盖变化已经是不可避免。土地利用与土地覆盖变化不仅对生态系统的要素、结构和功能产生深远的影响, 也会对全球变化产生反馈作用。针对土地利用与土地覆盖变化的过程、驱动机制以及在各个方面可能产生的生态环境效应的科学研究已经全面开展。该文综述了土地利用与土地覆盖变化对气候、土壤、生物地球化学循环、生物多样性以及区域生态环境等影响方面的研究进展, 并提出了相关研究的前沿方向展望。随着新技术的不断发展, 学者们将更多地侧重预测未来全球变化背景下的土地利用与土地覆盖变化趋势、合理性以及适应性, 为可持续发展提供基础资料和理论依据。     

土地利用与土地覆盖变化对生态系统的影响

随着人口的增长和人类社会的发展, 土地利用与土地覆盖变化已经是不可避免。土地利用与土地覆盖变化不仅对生态系统的要素、结构和功能产生深远的影响, 也会对全球变化产生反馈作用。针对土地利用与土地覆盖变化的过程、驱动机制以及在各个方面可能产生的生态环境效应的科学研究已经全面开展。该文综述了土地利用与土地覆盖变化对气候、土壤、生物地球化学循环、生物多样性以及区域生态环境等影响方面的研究进展, 并提出了相关研究的前沿方向展望。随着新技术的不断发展, 学者们将更多地侧重预测未来全球变化背景下的土地利用与土地覆盖变化趋势、合理性以及适应性, 为可持续发展提供基础资料和理论依据。     

土地利用变化对土壤有机碳的影响研究进展

土壤有机碳是陆地碳库的重要组成部分,也是当前全球碳循环和全球变化研究的热点。土地利用/覆被变化及土地管理变化通过影响土壤有机碳的储量和分布,进而影响温室气体排放和陆地生态系统的碳通量。研究土地利用变化影响下的土壤有机碳储量及其动态变化规律,有助于加深理解全球气候变化与土地利用变化之间的关系。在阅读国内外有关文献的基础上,分别从土地利用及其管理方式变化的角度,概括了土地利用变化对土壤有机碳的影响过程与机理;针对当前研究的两大类方法,即实验方法和模型方法,分类详细介绍了它们各自的特点以及存在的一些问题。在此基础上,提出今后土地利用变化对土壤有机碳影响研究的发展趋势。     

应用SWAT模型研究潮河流域土地利用和气候变化对径流的影响

为定量分析潮河流域土地利用和气候变化对流域径流变化的影响,应用SWAT模型对流域上游至下游的大阁、戴营和下会3个水文站径流进行模拟,采用情景法分析径流对土地利用和气候变化的响应。在模型校准期和验证期采用两个参数:p因子和r因子来评价模拟的拟合度及不确定性。结果表明,3个水文站在校准期和验证期的p因子值分别为:0.70和0.77,0.87和0.82,0.92和0.78,r因子值分别为0.63和0.90,0.97和0.79,0.88和0.92,评价整个流域模拟有效性的模型目标函数g最佳值为0.66,说明该模型对潮河流域的产水量模拟具有很好的适用性。以1981—1990年为基准期,1991—2000年流域土地利用变化造成年径流量减少了4.10 mm,而气候变化导致年径流增加了29.68 mm;2001—2009年土地利用变化造成年径流量减少2.98mm,气候变化造成年径流量减少了14.30 mm。与1999年土地利用条件模拟径流值相比,几种极端情景法模拟分析结果表明:灌木林地情景下年径流增加了158.2%,草地情景下年径流增加了4.1%,林地和耕地情景下年径流分别减少23.7%和41.7%;不同气候变异情景模拟结果显示,径流对降水的变化敏感性高于对温度变化的敏感性,降水每增加10%,径流平均增加23.9%。温度每增加12%,径流平均减少6%。因此,在气候变化背景下,优化土地利用结构与方式是实现流域水资源科学管理的途径之一。     

Introduction to the Special Section on Alternative Futures for Great Basin Ecosystems

Natural and anthropogenic processes are causing extensive and rapid ecological, social, and economic changes in arid and semiarid ecosystems worldwide. Nowhere are these changes more evident than in the Great Basin of the western United States, a region of 400,000 km² that largely is managed by federal agencies. Major drivers of ecosystems and human demographics of the Great Basin include human population growth, grazing by domestic livestock, extraction of minerals, development and production of energy, changes in fire and other disturbance regimes, and invasion of non-native annual plants. Exploration of alternative futures may increase the ability of management and policy to maximize the system's resistance and resilience to changes in climate, disturbance regimes, and anthropogenic perturbations. This special section examines the issues facing the Great Basin and then provides examples of approaches to predicting changes in land cover and avifaunal distributions under different management scenarios. Future sustainability of the Great Basin's natural and human systems requires strong, collaborative partnerships among research and management organizations that are capable of obtaining public support and financial resources and developing effective policies and institutional mechanisms.     

Laser-induced time-resolved photoacoustic calorimetry study on photo-dissociation of human and bovine oxyhemoglobin

The dynamics of the enthalpy and volume changes related to the photo-dissociation of oxygen from human and bovine oxyhemoglobin are investigated by nanosecond time-resolved photoacoustic calorimetry (PAC). The values of enthalpy and volume change associated with the above process are deltaH = 37.8 +/- 3 kcal/mol, deltaV = 5.0 +/- 1 ml/mol for human HbO(2); and deltaH = 35.7 +/- 3.5 kcal/mol, deltaV = 4.8 +/- 1 ml/mol for bovine HbO(2), respectively. A possible explanation for the similar values between both human and bovine oxyhemoglobin is proposed. In addition, the PAC results for human HbO(2) and HbCO are compared and discussed.     

基于MODIS-归一化植被指数的广东省植被覆盖与土地利用变化研究

基于MODIS-NDVI遥感植被指数,利用像元二分模型进行植被覆盖度提取,结合趋势分析和显著性检验等方法,对2000—2020年间广东省的植被覆盖时空变化特征进行分析,并结合土地利用变化图谱,探究土地利用类型对植被覆盖时空变化的驱动作用。结果表明：(1)2000—2020年,广东省植被覆盖度整体以0.23%/a的变化率呈波动增长趋势,但空间异质性显著,呈现出以珠三角地区为中心向外辐射递增的趋势;(2)广东省多年平均植被覆盖度介于0.7—0.76,以中高和高植被覆盖度为主,低植被覆盖区约占研究区总面积的4.37%。全省以植被改善为主(78.18%),显著和极显著退化区域占全区面积的5.84%,主要集中分布在珠三角、粤东沿海以及粤西沿海等地区;(3)研究区以耕地与林地的图谱单元互换为主要土地利用变化特征,而城乡、工矿、居民用地在耕地和林地的占用和补充过程中起了重要的作用,反映出城乡建设过程中对耕地和林地的大量占用;植被覆盖变化与土地利用变化存在响应联系,且各土地利用类型对植被覆盖度的贡献各异;向城乡、工矿、居民用地转化的图谱与植被显著和极显著退化区高度重合,说明耕地和林地向城乡、工矿、居民...     

人工绿洲对夏季气候变化趋势的影响

在绿洲的气候环境效应方面 ,此前的研究主要是基于个别地点的短期 (几天或几个月 )观测资料进行对比 ,分析绿洲与荒漠之间的要素差异和能量交换机制。通过细致筛选那些观测环境变化小、人口密度低、没有进行大规模水土开发地区的气象站 ,建立了反映背景变化的气候序列 ,同时选择不同地区的气象站建立了绿洲气候序列 ,分析背景与绿洲在气温、降水、水汽压、蒸发、风速等 9个气候因子近 5 0 a来气候趋势变化率的差异 ,研究绿洲发展对长年代气候变化的综合影响。结果表明 ,绿洲发展产生的气候环境效应在影响局部地区长期气候变化趋势方面是十分明显的。在夏季 ,绿洲平均气温的增温变化趋势要小于背景变化趋势 ,有些绿洲地区如吐 -善 -托盆地和叶尔羌河流域绿洲气温变化趋势还略呈下降趋势。绿洲地区对最高气温的变化趋势有着明显的抑制作用。其中 ,叶尔羌河流域绿洲和塔里木河中游地区绿洲最高气温变化趋势略呈下降趋势。绿洲地区对最低气温上升的变化趋势有一定的加强影响 ,绿洲效应使日较差正在变的越来越小。夏季绿洲对空中水汽压的增加十分明显 ,使蒸发潜力变得越来越弱 ,对降水有一定程度的增加作用。绿洲效应最为显著的一个方面是风速的变化 ,绿洲使平均风速和大风日数大幅度减少     

Natural history collections as windows on evolutionary processes

Natural history collections provide an immense record of biodiversity on Earth. These repositories have traditionally been used to address fundamental questions in biogeography, systematics and conservation. However, they also hold the potential for studying evolution directly. While some of the best direct observations of evolution have come from long‐term field studies or from experimental studies in the laboratory, natural history collections are providing new insights into evolutionary change in natural populations. By comparing phenotypic and genotypic changes in populations through time, natural history collections provide a window into evolutionary processes. Recent studies utilizing this approach have revealed some dramatic instances of phenotypic change over short timescales in response to presumably strong selective pressures. In some instances, evolutionary change can be paired with environmental change, providing a context for potential selective forces. Moreover, in a few cases, the genetic basis of phenotypic change is well understood, allowing for insight into adaptive change at multiple levels. These kinds of studies open the door to a wide range of previously intractable questions by enabling the study of evolution through time, analogous to experimental studies in the laboratory, but amenable to a diversity of species over longer timescales in natural populations.     

基于过程模型的青藏高原湿地甲烷排放格局评估

甲烷(CH_4)是大气中最丰富的碳氢化合物,是仅次于二氧化碳(CO_2)的温室气体。湿地是甲烷的重要来源,在全球碳循环中发挥着重要作用,其排放的甲烷占所有天然甲烷排放源的70%,占全球甲烷排放总量的24.8%。青藏高原平均海拔4000 m以上,占有中国约三分之一的湿地。近几十年来,由于全球气候变暖和降水增加,该地区甲烷排放率和湿地面积都发生着巨大变化,因此,青藏高原湿地CH_4排放的长期变化在很大程度上仍存在较大的不确定性。利用TRIPLEX-GHG模型模拟了青藏高原湿地1978—2008年CH_4排放的动态特征,研究结果表明:(1)1978—2008年青藏高原湿地CH_4排放速率呈逐渐增加趋势。(2)青藏高原大多数湿地区域CH_4排放速率为0—6.13 g CH_4 m~(-2 )a~(-1);东北部分湿地区域CH_4排放速率为6.14—20.19 g CH_4 m~(-2 )a~(-1);较高的CH_4排放速率分布于青藏高原南部湿地区域,为56.14—74.97 g CH_4 m~(-2 )a~(-1)。(3)青藏高原湿地CH_4排放量在1978、1990、2000年和2008年分别为0.21、0.23、0.27和0.32 Tg CH_4 a~(-1)。在1978—1990年,尽管CH_4排放速率增加,但湿地面积减少,因此这一时期青藏高原湿地CH_4排放量并未发生明显变化。随后由于降水增加和冰川融化,使得湿地面积逐渐增加,青藏高原湿地CH_4排放量也呈现增加趋势。     

全球气候变化对野生动物的影响

人类活动所引起的温室气体增加以及由此造成的全球气候变化和对全球生态环境的影响正越来越引起人们的关注,在全球气候变化对野生动物影响的研究中发现,随着全球气温变暖,野生动物的分布区整体上向北移,物修期提前,动物的繁殖及其种群大小,不同的种类做出不同的响应,有的受益于全球变暖,繁殖增加,成活率高,种群壮大,有的受制于这一变化,种群逐渐缩小甚至面临灭绝的威胁,总的来看,全球气候变暖使更多的野生动物无所适从,因此,加强对气候变化在不同层面上对野生动物影响机制的研究,调整野生动物保护措施,对野生动物及其生境的保护,维持生态系统多样性将显得十分重要。     

气候变化对鸟类影响：长期研究的意义

过去一个多世纪全球气候发生了明显变化,地球表面温度正在逐渐变暖。已有大量研究结果表明,鸟类已经在种群动态变化、生活史特性以及地理分布范围等方面对全球气候变化作出了相应的反应。根据全球范围内气候变化对鸟类影响的研究资料,尤其是北美和欧洲的一些长期研究项目的成果,综述了气候变化对鸟类分布范围、物候、繁殖和种群动态变化等方面的可能影响。这些长期研究项目为探讨气候变化在个体和种群的水平上如何长时间地影响鸟类提供了独特的机会,对未来中国鸟类学研究也会有所裨益。     

Impact of expected climate change on mangroves

There is a consensus of scientific opinion that the activities of man will cause a significant change in the global climate over the next hundred years. The rising level of carbon dioxide and other industrial gases in the atmosphere may lead to global warming with an accompanying rise in sea-level. Mangrove ecosystems grow in the intertidal zones in tropical and sub-tropical regions and are likely to be early indicators of the effects of climate change. The best estimates of predicted climate change in the literature are presented. It is suggested that a rise in mean sea-level may be the most important factor influencing the future distribution of mangroves but that the effect will vary dramatically depending on the local rate of sea-level rise and the availability of sediment to support reestablishment of the mangroves. The predicted rise in mean air temperature will probably be of little consequence to the development of mangroves in general but it may mean that the presence of mangroves will move further north and south, though this will depend on a number of additional factors. The effect of enhanced atmospheric CO₂ on the growth of mangroves is unknown at this time but that there is some evidence that not all species of mangroves will respond similarly. The socio-economic impacts of the effects of climate on mangrove ecosystems may include increased risk of flooding, increased erosion of coast lines, saline intrusion and increased storm surges.     

Effects of climate change and crop planting structure on the abundance of cotton bollworm,Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

The interactions between plants and insects play an important role in ecosystems. Climate change and cropping patterns can affect herbivorous pest insect dynamics. Understanding the reasons for population fluctuations can help improve integrated pest management strategies. Here, a 25‐year dataset on climate, cropping planting structure, and the population dynamics of cotton bollworms (Helicoverpa armigera) from Bachu County, south Xinjiang, China, was analyzed to assess the effects of changes in climate and crop planting structure on the population dynamics of H. armigera. The three generations of H. armigera showed increasing trends in population size with climate warming, especially in the third generation. The relative abundances of the first and second generations decreased, but that of the third generation increased. Rising temperature and precipitation produced different impacts on the development of different generations. The population numbers of H. armigera increased with the increase in the non‐Bacillus thuringiensis (Bt) cotton‐planted area. Asynchrony of abrupt changes existed among climate change, crop flowering dates, and the phenology of H. armigera moths. The asynchronous responses in crop flowering dates and phenology of H. armigera to climate warming would expand in the future. The primary factors affecting the first, second, and third generations of moths were T_mean in June, the last appearance date of the second generation of moths, and the duration of the third generation of moths, respectively. To reduce the harm to crops caused by H. armigera, Bt cotton should be widely planted.     

砚瓦川流域河川基流变化规律及其驱动因素

基流是黄河径流的重要补给来源,目前大部分研究都集中在黄河流域径流变化规律上,而对维持河道基本流量和生态环境安全方面发挥着重要作用的基流却研究较少。因此,基于黄河中游砚瓦川流域1981-2016年的水文、气象及植被资料,选用9种数值模拟法对基流进行分割并分析其适用性,利用Mann-Kendall法和滑动t检验法对基流进行了趋势分析和突变点检验,并定性和定量的探讨了气候变化和植被变化对流域河川基流变化的影响。结果表明：（1）在各种基流分割方法中,Lyne-Hollick滤波法的计算结果精度较高,且分割结果比较符合实际日基流变化规律,因此更适用于研究区的基流估算;（2）流域多年平均河川基流量和基流指数BFI （基流量与河川流量的比值）分别为0.152 m³/s和0.58,两者在年际上均呈现极显著的减少趋势（P<0.01）,且分别于1993年和2006年附近发生了突变;（3）基流量与潜在蒸散发量相关性最强,流域降水量、潜在蒸散发量及NDVI的变化对基流量变化的贡献率分别为-99.1%、113.3%和85.8%,可见潜在蒸散发量和NDVI的增加是引起基流量减少的主要原因,而基流指数与NDVI相关性最强,且呈负相关关系,流域降水量、潜在蒸散发量及NDVI的变化对基流指数变化的贡献率分别为41.3%、-27.7%和86.5%,这说明流域NDVI的增加对流域基流指数的降低起到了主导作用。     

黑龙江省20世纪森林变化及对氧气释放量的影响

随着对大气环境质量研究的深入,大气中氧气含量变化也引起了关注。森林是固碳释氧的重要生态系统,黑龙江省近百年来,森林面积减少了37.163%,估算由此导致的森林氧气释放量变化,对研究大气氧气含量变化具有重要意义。以黑龙江省1900年、1949年、1986年和2009年为时间断面,采用C-FIX模型及碳氧平衡方法,模拟并分析了20世纪黑龙江省森林氧气释放量及其变化。结果表明:(1)黑龙江省20世纪森林面积减少了106667.570 km2,森林覆盖率减少了23.568%。除樟子松(Pinus sylvestris var.mongolica)林、针阔混交林面积有所增加外,其它树种的森林面积均减少,其中云冷杉(Picea asperata and Abies nephrolepis)林及红松(Pinus koraiensis)林面积减少超过80%,空间上以松嫩平原及三江平原减少最为显著;(2)森林年氧气释放量百年来减少了5621.560万t,减少近三分之一,其空间变化明显,西南部森林氧气释放量由百年前的最高区域变为最低区域,三江平原释放氧气的森林区域明显减少;(3)百年来各行政区森林年氧气释放量除伊春微弱增加外,其余均呈减少趋势。其中大庆市、齐齐哈尔市减少显著,减少了90%以上;(4)控制实验表明,森林面积变化导致黑龙江省区域森林年氧气释放量减少了50%。人类活动引起的森林面积减少,是导致黑龙江省森林氧气释放量减少的主要因素。     

Effects of seasonal precipitation change on soil respiration processes in a seasonally dry tropical forest

Precipitation is projected to change intensity and seasonal regime under current global projections. However, little is known about how seasonal precipitation changes will affect soil respiration, especially in seasonally dry tropical forests. In a seasonally dry tropical forest in South China, we conducted a precipitation manipulation experiment to simulate a delayed wet season (DW) and a wetter wet season (WW) over a three‐year period. In DW, we reduced 60% throughfall in April and May to delay the onset of the wet season and irrigated the same amount water into the plots in October and November to extend the end of the wet season. In WW, we irrigated 25% annual precipitation into plots in July and August. A control treatment (CT) receiving ambient precipitation was also established. Compared with CT, DW significantly increased soil moisture by 54% during October to November, and by 30% during December to April. The treatment of WW did not significantly affect monthly measured soil moisture. In 2015, DW significantly increased leaf area index and soil microbial biomass but decreased fine root biomass. In contrast, WW significantly decreased fine root biomass and forest floor litter stocks. Soil respiration was not affected by DW, which could be attributed to the increased microbial biomass offsetting the decrease in fine root biomass. In contrast, WW significantly increased soil respiration from 3.40 to 3.90 μmol m^?2 s^?1 in the third year, mainly due to the increased litter decomposition and soil pH (from 4.48 to 4.68). The present study suggests that both a delayed wet season and a wetter wet season will have significant impacts on soil respiration‐associated ecosystem components. However, the ecosystem components can respond in different directions to the same change in precipitation, which ultimately affected soil respiration.     

基于参照系的中国陆地生态系统质量变化研究

提升生态系统质量（ESQ）是国家生态文明建设的重大需求和生态治理工程的最终目标。目前有关生态系统功能、健康和质量的评估以受气候主导的现实值为主，不同地区之间评价结果的可比性较低，难以满足国家生态系统管理的需求。采用基于参照系的生态系统质量评估框架，按照由中国生态地理分区和植被类型划分出的168个评估单元，以国家自然保护区核心区、中国生态系统研究网络（CERN）永久观测样地以及生产力主要受气候影响的区域等较少受人类活动干扰且生态系统结构和功能优良的生态系统作为参照系，评估了1990—2015年基于参照系的中国陆地生态系统质量（ESQ''）及其变化情况。结果表明：与参照生态系统相比，中国陆地生态系统质量指数平均值总体偏低28%。1990—2000年和2000—2015年ESQ''全国平均值分别下降1.2%和上升3.69%。ESQ''转变比较明显的区域集中分布在"陕-甘-宁"的黄土高原丘陵沟壑水土保持生态功能区、长白山地区和西南石漠化治理工程县域。在这些区域实施的退耕还林还草、防护林和石漠化治理工程等措施对提升生态系统结构、功能和稳定性发挥了重要作用，从而促使生态系统质量的改善。基于参照系的生态系统质量评估方法可以在一定程度上消除不同区域气候波动差异对质量评估的影响，为量化人类活动对生态系统的影响提供了一种可行的新途径，可为我国的生态系统和土地利用管理提供参考。建议未来加强全国不同区域、不同类型的参照生态系统联网观测，并重点关注未来气候变化及生态系统功能权衡关系对生态系统质量的影响。     

The dynamics of the dune vegetation on the Polish Baltic coast

This paper deals with the Baltic coastline in Poland. Features of the climate, geomorphology, substratum, soils and vegetation are outlined. The historical forest succession is based on the results of palynological studies of fossil soils. The present-day dynamics of the plant communities are examined from the viewpoint of primary succession, regression, regeneration and secondary succession. The primary succession on moving dunes is described with particular reference to deflation fields. Attention is drawn to the spatial changes in the communities from the 16th to the 20th century as a result of natural and human factors. This study shows that during the 19th and 20th centuries and especially in the last 25 years, the dynamics of the dunes and their vegetation have been much reduced, owing to the widespread stabilization of the substratum by forests and the ongoing abrasion of the coastal dunes.