西北干旱区白刺属植物适生环境的模拟分析

白刺属(Nitraria L.)植物是古地中海第三纪孑遗植物,对我国西北干旱、半干旱地区具有极高的生态效益.本研究基于MaxEnt模型和ArcGIS软件及其SDM工具箱预测了过去到未来不同时期下白刺属6个物种在我国的潜在适生区及其迁移路线,以期为该属植物的保护及资源利用方面提供一定的理论依据.结果表明:白刺属植物当代在...     

Genetic structure and historical demography of Malus sieversii in the Yili Valley and the western mountains of the Junggar Basin,Xinjiang, China

 Malus sieversii, a wild progenitor of domesticated apple, is distributed in western Xinjiang of China, eastern part of Kazakhstan and Kyrgyzstan in Central Asia. To well understand the genetic structure and the historical demography of this important germplasm resource, we sampled 15 populations with 110 individuals of Malus sieversii from the Yili Valley and the western mountains of the Junggar Basin, Xinjiang, and sequenced two nrDNA fragments for these 110 individuals. Meanwhile, we modeled and compared species distributions under the current and the Last Glacial Maximum climatic conditions. The results showed that populations of M. sieversii from Xinjiang had low levels of genetic diversity and genetic differentiation. During the LGM period, populations of M. sieversii had lost their northern distributions in the western mountains of the Junggar Basin. M. sieversii has experienced a demographic expansion from the south of the Yili Valley to the north of the western mountains of the Junggar Basin during the warm interglacial epochs. Due to the high sensibility of M. sieversii to disturbance, we proposed more attention should be paid to the M. sieversii populations in the western mountains of the Junggar Basin.     

The current and future potential distribution of Melaleuca quinquenervia

Melaleuca quinquenervia (broad-leaved paperbark) is a tree native to Australia, Papua New Guinea and New Caledonia that has become moderately to highly invasive in a number of countries over the last century. Although a synoptic view of the invasion would be of considerable use in devising appropriate control strategies, little effort has been applied to investigate the potential distribution of this invasive species. A climate suitability analysis was undertaken in this study, to assess the risk of geographic range expansion of M . quinquenervia under current climate and how this distribution will be modified by climate change during the 2080s. CLIMEX™ was used to infer the climatic requirements of M . quinquenervia from observations in both the native and exotic range. The accuracy of the developed model was assessed using independent naturalised observations of the species in Asia, Africa, Oceania and the Caribbean. Projections of climatic suitability indicate considerable scope for further invasion, with the most suitable areas occurring adjacent to existing populations in south-east Asia, the Caribbean, Central and South America and the Gulf coast in southern USA. Under future climates, model projections indicate there will be a marked contraction of suitable habitat in most regions and a slight poleward range expansion within south-eastern China, southern Europe and northern New Zealand.     

Impact of climate change on the streamflow in the glacierized Chu River Basin,Central Asia

Catchments dominated by meltwater runoff are sensitive to climate change as changes in precipitation and temperature inevitably affect the characteristics of glaciermelt/snowmelt, hydrologic circle and water resources. This study simulated the impact of climate change on the runoff generation and streamflow of Chu River Basin(CRB), a glacierized basin in Central Asia using the enhanced Soil and Water Assessment Tool(SWAT). The model was calibrated and validated using the measured monthly streamflow data from three discharge gauge stations in CRB for the period 1961–1985 and was subsequently driven by downscaled future climate projections of five Global Circulation Models(GCMs) in Coupled Model Inter-comparison Project Phase 5(CMIP5) under three radiative forcing scenarios(RCP2.6, RCP4.5 and RCP8.5). In this study, the period 1966–1995 was used as the baseline period, while 2016–2045 and 2066–2095 as the near-future and far-future period, respectively. As projected, the climate would become warmer and drier under all scenarios in the future, and the future climate would be characterized by larger seasonal and annual variations under higher RCP. A general decreasing trend was identified in the average annual runoff in glacier(–26.6% to –1.0%), snow(–21.4% to +1.1%) and streamflow(–27.7% to –6.6%) for most of the future scenario periods. The projected maximum streamflow in each of the two future scenarios occurred one month earlier than that in the baseline period because of the reduced streamflow in summer months. Results of this study are expected to arouse the serious concern about water resource availability in the headwater region of CRB under the continuously warming climate. Changes in simulated hydrologic outputs underscored the significance of lowering the uncertainties in temperature and precipitation projection.     

Glacier variations and their response to climate change in an arid inland river basin of Northwest China

Glaciers are a critical freshwater resource of river recharge in arid areas around the world. In recent decades, glaciers have shown evidence of retreat due to climate change, and the accelerated ablation of glaciers and associated impacts on water resources have received widespread attention. Glacier variations result from climate change, so they can serve as an indicator of climate change. Considering the climatic differences in different elevation ranges, it is worthwhile to explore whether different responses exist between glacier area and air temperature in each elevation zone. In this study, we selected a typical arid inland river basin(Sugan Lake Basin) in the western Qilian Mountains of Northwest China to analyze the glacier variations and their response to climate change. The glacier area data from 1989 to 2016 were delineated using Landsat Thematic Mapper(TM), Enhanced TM+(ETM+) and Operational Land Imager(OLI) images. We compared the relationships between glacier area and air temperature at seven meteorological stations in the glacier-covered areas and in the Sugan Lake Basin, and further analyzed the relationship between glacier area and mean air temperature of the glacier surfaces in July–August in the elevation range of 4700–5500 m a.s.l. by the linear regression method and correlation analysis. In addition, based on the linear regression relationship established between glacier area and air temperature in each elevation zone, we predicted glacier areas under future climate scenarios during the periods of 2046–2065 and 2081–2100. The results indicate that the glaciers experienced a remarkable shrinkage from 1989 to 2016 with a shrinkage rate of –1.61 km2/a(–0.5%/a), and the rising temperature is the decisive factor dominating glacial retreat; there is a significant negative linear correlation between glacier area and mean air temperature of the glacier surfaces in July–August in each elevation zone from 1989 to 2016. The variations in glaciers are far less sensitive to changes in precipitation than to changes in air temperature. Due to the influence of climate and topographic conditions, the distribution of glacier area and the rate of glacier ablation first increased and then decreased in different elevation zones. The trend in glacier shrinkage will continue because air temperature will continue to increase in the future, and the result of glacier retreat in each elevation zone will be slightly slower than that in the entire study area. Quantitative glacier research can more accurately reflect the response of glacier variations to climate change, and the regression relationship can be used to predict the areas of glaciers under future climate scenarios. These conclusions can offer effective references for assessing glacier variations and their response to climate change in arid inland river basins in Northwest China as well as other similar regions in the world.     

Runoff of arid and semi-arid regions simulated and projected by CLM-DTVGM and its multi-scale fluctuations as revealed by EEMD analysis

Runoff is a major component of the water cycle,and its multi-scale fluctuations are important to water resources management across arid and semi-arid regions.This paper coupled the Distributed Time Variant Gain Model(DTVGM)into the Community Land Model(CLM 3.5),replacing the TOPMODEL-based method to simulate runoff in the arid and semi-arid regions of China.The coupled model was calibrated at five gauging stations for the period 1980–2005 and validated for the period 2006–2010.Then,future runoff(2010–2100)was simulated for different Representative Concentration Pathways(RCP)emission scenarios.After that,the spatial distributions of the future runoff for these scenarios were discussed,and the multi-scale fluctuation characteristics of the future annual runoff for the RCP scenarios were explored using the Ensemble Empirical Mode Decomposition(EEMD)analysis method.Finally,the decadal variabilities of the future annual runoff for the entire study area and the five catchments in it were investigated.The results showed that the future annual runoff had slowly decreasing trends for scenarios RCP 2.6 and RCP 8.5 during the period 2010–2100,whereas it had a non-monotonic trend for the RCP 4.5 scenario,with a slow increase after the 2050 s.Additionally,the future annual runoff clearly varied over a decadal time scale,indicating that it had clear divisions between dry and wet periods.The longest dry period was approximately 15 years(2040–2055)for the RCP 2.6 scenario and 25 years(2045–2070)for the RCP 4.5 scenario.However,the RCP 8.5 scenario was predicted to have a long dry period starting from 2045.Under these scenarios,the water resources situation of the study area will be extremely severe.Therefore,adaptive water management measures addressing climate change should be adopted to proactively confront the risks of water resources.     

The current and future potential distribution of Cytisus scoparius: a weed of pastoral systems, natural ecosystems and plantation forestry

Cytisus scoparius is a serious weed of pastoral systems, natural ecosystems and plantation forestry, which has become invasive in a number of countries. CLIMEX™ was used to infer the climatic requirements of C. scoparius from its native range, as well as its current range as an exotic in the United States and New Zealand. The parameterised model was used to examine the invasive potential of C. scoparius under current and future climatic conditions, assuming a range of climate-change scenarios. The modelled global potential distribution of C. scoparius compared favourably with the known distributions, in both the fitted and validation dataset, encompassing almost all temperate and Mediterranean regions. The predicted distribution also included most sub-tropical regions and extended into continental areas in North America and Europe and savanna regions in Africa. Under current climate, the projected potential distribution exceeded the known distribution. Places most at risk from range expansion include China, Australia, Argentina and North America, as C. scoparius is already present, but has not yet colonised all areas with apparently high climatic suitability. Climate change is likely to lead to a poleward shift in the range of C. scoparius and a contraction of areas of suitable climate for the species in southern Europe, central Africa, Australia, China, Brazil and the southern United States. With climate change, currently uncolonised areas within northern Scandinavia, southern Canada and western regions of the Russian Federation are projected to become climatically suitable.     

基于Holdridge分类系统的东北地区主要树种的水热分布类群

根据东北地区树种分布资料和233个气象站资料,利用Holdridge生命地带分类系统计算了东北地区50种主要树种的Holdridge生命地带分类系统的年生物温度(BT)、可能蒸散(APE)、年降水量(PREC)和可能蒸散率(PER)。构建了Holdridge指标与树种分布的纬度、经度和海拔高度的回归模型,定量的分析了东北地区树种分布的气候规律。综合年生物温度(BT)和可能蒸散率(PER)两个气候指标将50种主要树种划分为8个水热指标类群,分别为寒温耐旱型、寒温湿润型,寒温潮湿型,中温耐旱型,中温湿润型,中温潮湿型,暖温耐旱型和暖温湿润型。     

东北地区主要树种的分布与Thornthwaite指标的关系

根据树种的分布资料和气象资料,采用桑斯威特(Thornthwaite)方法计算东北地区50种主要树种的潜在可能蒸散(PE)和湿润指数(IM),利用半峰宽法计算热量指数PE的最适范围,并构建Thornthwaite气候指标与树种分布的地理三维要素(纬度、经度和海拔高度)的回归模型,分析东北地区主要树种水热分布规律。综合潜在可能蒸散(PE)和湿润指数(IM)两个气候指标,将东北地区主要树种划分为寒温湿润型,寒温潮湿型,中温耐旱型,中温湿润型,中温潮湿型,暖温耐旱型、暖温湿润型和暖温潮湿型等8个水热指标类群,并论述了东北地区主要树种的水热分布格局。     

气候变化对新疆意大利蝗潜在分布的影响

意大利蝗Calliptamus italicus(L.)是新疆草原主要优势蝗虫之一,每年给新疆畜牧业经济带来严重损失,气候变化对其潜在分布影响的预测对其科学防治有重要意义。本研究采用意大利蝗的分布数据和生物气候数据,结合MaxEnt模型和ArcGIS软件,预测了BCC_CSM1.1气候模式下政府间气候变化专门委员会第五次工作报告(IPCC AR5)采用的RCP2.6、RCP4.5和RCP8.5三种气候情景在2021-2040年(2030s)、2041-2060年(2050s)和2061-2080年(2070s)的意大利蝗新疆潜在适生区分布范围。结果表明:在BCC_CSM1.1的各情景下,意大利蝗适生区在北疆及天山一带分布格局基本保持不变,但高度适生区面积都有所增加,其中在天山和阿尔泰山地区,意大利蝗中、高度适生区范围将向更高海拔区域蔓延,在北疆阿勒泰地区高度适生区明显增加。极端水分条件和水热条件对意大利蝗在新疆潜在分布发挥主要作用,其中4月、10月、3月和11月降水量对意大利蝗在新疆潜在分布影响最大,因其直接影响土壤相对含水量和土壤温度,从而决定意大利蝗卵的存活量。     

Attribution analysis and multi-scenario prediction of NDVI drivers in the Xilin Gol grassland,China

Grassland degradation is influenced by climate change and human activities, and has become a major obstacle for the development of arid and semi-arid areas, posing a series of environmental and socio-economic problems. An in-depth understanding of the inner relations among grassland vegetation dynamics, climate change, and human activities is therefore greatly significant for understanding the variation in regional environmental conditions and predicting future developmental trends. Based on MOD...     

东北地区主要树种分布与气候的关系

根据东北地区树种分布资料和气象资料,计算了东北地区50种主要树种的Kira温暖指数(WI)、温暖指数的全范围和最适范围以及徐文铎提出的湿度指数(HI)。建立了东北地区气候因子与树种地理分布的回归模型,并对气候因素与树种地理分布的相关关系进行了分析。综合50种主要树种的水热指标值,将其划分为寒温湿润型,寒温潮湿型,中温耐旱型,中温湿润型,中温潮湿型,暖温耐旱型和暖温湿润型7个Kira水热指标分布类群,论述了东北地区主要树种沿热量和水分梯度的分布格局。     

气候变化条件下悬铃木方翅网蝽在中国的适生性分析

悬铃木方翅网蝽Corythucha ciliata是2002年入侵我国的有害生物,严重为害悬铃木等园林植物。本文利用CLIMEX和GIS软件,并结合悬铃木方翅网蝽已知的地理分布和生物学数据,对其在当前(1981年-2010年)及未来(2011年-2040年、2041年-2070年和2071年-2100年)气候条件下中国的适生区进行预测。结果表明:当前气候条件下,悬铃木方翅网蝽在我国适生范围较广,适生区占我国内陆总面积的61.27%,主要集中在我国东半部地区,其中高度适生区主要集中在华南、华中大部、华东大部及西南局部地区;未来气候变暖情境下,悬铃木方翅网蝽的适生区呈现向东北方向扩展的趋势,总适生范围不断增大,且适生程度增加。研究结果为有效控制悬铃木方翅网蝽提供了科学参考依据,对于现已发生和预测出的潜在适生分布区,要加强检疫,防止其进一步扩散传播。     

Simulating hydrological responses to climate change using dynamic and statistical downscaling methods: a case study in the Kaidu River Basin,Xinjiang, China

Climate change may affect water resources by altering various processes in natural ecosystems. Dynamic and statistical downscaling methods are commonly used to assess the impacts of climate change on water resources. Objectively, both methods have their own advantages and disadvantages. In the present study, we assessed the impacts of climate change on water resources during the future periods (2020-2029 and 2040-2049) in the upper reaches of the Kaidu River Basin, Xinjiang, China, and discussed the uncertainties in the research processes by integrating dynamic and statistical downscaling methods (regional climate models (RCMs) and general circulation modes (GCMs)) and utilizing these outputs. The reference period for this study is 1990-1999. The climate change trend is represented by three bias-corrected RCMs (i.e., Hadley Centre Global Environmental Model version 3 regional climate model (HadGEM3-RA), Regional Climate Model version 4 (RegCM4), and Seoul National University Meso-scale Model version 5 (SUN-MM5)) and an ensemble of GCMs on the basis of delta change method under two future scenarios (RCP4.5 and RCP8.5). We applied the hydrological SWAT (Soil and Water Assessment Tool) model which uses the RCMs/GCMs outputs as input to analyze the impacts of climate change on the stream flow and peak flow of the upper reaches of the Kaidu River Basin. The simulation of climate factors under future scenarios indicates that both temperature and precipitation in the study area will increase in the future compared with the reference period, with the largest increase of annual mean temperature and largest percentage increase of mean annual precipitation being of 2.4°C and 38.4%, respectively. Based on the results from bias correction of climate model outputs, we conclude that the accuracy of RCM (regional climate model) simulation is much better for temperature than for precipitation. The percentage increase in precipitation simulated by the three RCMs is generally higher than that simulated by the ensemble of GCMs. As for the changes in seasonal precipitation, RCMs exhibit a large percentage increase in seasonal precipitation in the wet season, while the ensemble of GCMs shows a large percentage increase in the dry season. Most of the hydrological simulations indicate that the total stream flow will decrease in the future due to the increase of evaporation, and the maximum percentage decrease can reach up to 22.3%. The possibility of peak flow increasing in the future is expected to higher than 99%. These results indicate that less water is likely to be available in the upper reaches of the Kaidu River Basin in the future, and that the temporal distribution of flow may become more concentrated.     

Modelling the biological invasion of Prosopis juliflora using geostatistical-based bioclimatic variables under climate change in arid zones of southwestern Iran

Invasive species have been the focus of ecologists due to their undesired impacts on the environment.The extent and rapid increase in invasive plant species is recognized as a natural cause of global-biodiversity loss and degrading ecosystem services.Biological invasions can affect ecosystems across a wide spectrum of bioclimatic conditions.Understanding the impact of climate change on species invasion is crucial for sustainable biodiversity conservation.In this study,the possibility of mapping the distribution of invasive Prosopis juliflora(Swartz)DC.was shown using present background data in Khuzestan Province,Iran.After removing the spatial bias of background data by creating weighted sampling bias grids for the occurrence dataset,we applied six modelling algorithms(generalized additive model(GAM),classification tree analysis(CTA),random forest(RF),multivariate adaptive regression splines(MARS),maximum entropy(Max Ent)and ensemble model)to predict invasion distribution of the species under current and future climate conditions for both optimistic(RCP2.6)and pessimistic(RCP8.5)scenarios for the years 2050 and 2070,respectively.Predictor variables including weighted mean of CHELSA(climatologies at high resolution for the Earth’s land surface areas)-bioclimatic variables and geostatistical-based bioclimatic variables(1979–2020),physiographic variables extracted from shuttle radar topography mission(SRTM)and some human factors were used in modelling process.To avoid causing a biased selection of predictors or model coefficients,we resolved the spatial autocorrelation of presence points and multi-collinearity of the predictors.As in a conventional receiver operating characteristic(ROC),the area under curve(AUC)is calculated using presence and absence observations to measure the probability and the two error components are weighted equally.All models were evaluated using partial ROC at different thresholds and other statistical indices derived from confusion matrix.Sensitivity analysis showed that mean diurnal range(Bio2)and annual precipitation(Bio12)explained more than 50% of the changes in the invasion distribution and played a pivotal role in mapping habitat suitability of P.juliflora.At all thresholds,the ensemble model showed a significant difference in comparison with single model.However,Max Ent and RF outperformed the others models.Under climate change scenarios,it is predicted that suitable areas for this invasive species will increase in Khuzestan Province,and increasing climatically suitable areas for the species in future will facilitate its future distribution.These findings can support the conservation planning and management efforts in ecological engineering and be used in formulating preventive measures.     

西北地区冬季地面风速特征及其与春夏季地表感热的关系

利用EOF、气候突变检测及相关统计方法,分析我国西北地区近37年（1970-2006）冬季地面风速的时空异常,并对近25年（1982-2006）西北干旱区春、夏季地表感热的时空异常变化及其与前期冬季风速的关系进行相应的研究。结果表明：近25年西北地区冬季风速下降趋势显著,20世纪70年代冬季地面风速普遍较大,80年代风...     

近52 a长白山苔原带生长季气候变化特征

利用长白山苔原带天池站1959-2010年6-9月气象数据,进行生长季气候变化分析。采用距平值、小波分析、Mann Kendall检验相结合的方法,进行温度、降水周期性变化与突变点的检验;采用线性倾向估计法,分析未来气候变化的趋势;并通过气候变化指数,反映其气候变化情况。结果显示：52 a来,长白山苔原带生长季经历了暖湿-冷干-暖湿-冷干-冷湿-冷干-暖干几个主要阶段,温度变化周期为5～10 a,降水变化周期为5 a和20 a.。温度变化的突变年份发生在1998年,降水变化较之温度变化复杂,其存在多个突变年份;各气象要素的变化趋势大都表现为显著的升高,其中温度的变化最为明显,风速、日照时数的变化甚微;霜冻日数与冰点日数均显著减少,极端温度大多出现在21世纪;伴随着>0.1 mm降雨日数的显著减小,长白山苔原带降水强度不断增加;与植物生长相关的生长季≥0 ℃积温、≥3 ℃积温和≥5 ℃积温在52 a间呈显著增加趋势,积温的增加将会对生长季的延长及植物生长起到显著的促进作用。     

Impacts of climate change on wheat anthesis and fusarium ear blight in the UK

Climate change will affect both growth of agricultural crops and diseases that attack them but there has been little work to study how its impacts on crop growth influence impacts on disease epidemics. This paper investigates how impacts of climate change on wheat anthesis date will influence impacts on fusarium ear blight in UK mainland arable areas. A wheat growth model was used for projections of anthesis dates, and a weather-based model was developed for use in projections of incidence of fusarium ear blight in the UK. Daily weather data, generated for 14 sites in arable areas of the UK for a baseline (1960–1990) scenario and for high and low CO₂ emissions in the 2020s and 2050s, were used to project wheat anthesis dates and fusarium ear blight incidence for each site for each climate change scenario. Incidence of fusarium ear blight was related to rainfall during anthesis and temperature during the preceding 6 weeks. It was projected that, with climate change, wheat anthesis dates will be earlier and fusarium ear blight epidemics will be more severe, especially in southern England, by the 2050s. These projections, made by combining crop and disease models for different climate change scenarios, suggest that improved control of fusarium ear blight should be a high priority in industry and government strategies for adaptation to climate change to ensure food security.     

基于改进的标准化降水指数的黄河中游干旱情势研究

提出了一种基于旬累积尺度的月标准化降水指数(SPI)计算方法,该方法不仅考虑了前期降雨量对区域当前旱情的影响,因而对旱情的评估更为客观,同时在实际应用中更具有时间上的灵活性,更能体现气象干旱的累积效应和预报的时效性。计算了黄河中游山西省境内近40a(1971-2009年)各旬干旱指数,分析结果表明改进的标准化降水指数能够很好地表征黄河中游山西省境内的历史旱情状况。引入国际上常用的多种未来气候情景,研究分析了未来气候变化下2021-2050年黄河中游山西省境内地区旱情发展的可能情势,结果表明其存在对农业不利影响加重的可能,需要引起水资源管理部门的重视。     

基于最大熵模型的沙棘绕实蝇适生性研究

沙棘绕实蝇(Rhagoletis batava Hering)是危害沙棘果实的重要害虫。本研究采用Maxent模型,在收集和整理沙棘绕实蝇全球地理分布信息的基础上,筛选出与该虫发生相关的11个关键环境变量,预测了当前及未来气候条件下该虫在全球以及我国的适生区和适生程度。在当前气候条件下,该虫在全球的适生范围主要集中在北温带地区,在我国的适生范围较广且适生程度较高;在2050年的两种气候情景下,沙棘绕实蝇在全球的适生区北界均向北移动,在我国的适生范围均略有扩大且适生区向西南部拓展。建议我国相关部门进一步加强针对沙棘绕实蝇的入侵防控工作。