摘　要： 物种分布模型已被广泛地应用于以保护区规划、气候变化对物种分布的影响等为目的的研究。回顾了已经得到广泛应用的多种物种分布模型，总结了评价模型性能的方法。基于物种分布模型的发展和应用以及性能评价中尚存在的问题，本文认为：在物种分布模型中集成样本选择模块能够避免模型预测过程中的过度拟合及欠拟合，增加变量选择模块可评估和降低变量之间自相关性的影响，增加生物因子以及将物种对环境的适应性机制（及扩散行为特征）和潜在分布模型进行结合，是提高模型预测性能的可行方案；在模型性能的评价方面，采用赤池信息量可对模型的预测性能进行客观评价。相关建议可为物种分布建模提供参考。

Aims Understanding the geographical distribution and patterns of endemic species is critical to biodiversity conservation and biogeographical history reconstruction of the area occupied by the species. The ecological niche models (ENMs) are useful techniques to explore the links between the species distribution and the environmental data. The displayed potential habitats for the species, in turn can enable the examination of the predictive abilities of various ENMs. We attempt to determine the potential geographic distributions of the Tertiary relic plant Gymnocarpos przewalskii based on the model of maximum entropy (MAXENT) and genetic algorithm for rule-set prediction (GARP). Methods Based on sixteen sampled localities and seven environmental layers (isothermality, maximum temperature, minimum temperature, annual precipitation, potential evapotranspiration ratio (PER), altitude and soil types), we conducted predictions of G. przewalskii using MAXENT and GARP models. The spatial distribution maps of G. przewalskii with the different environmental suitable values (MAXENT) or overlap index (GARP) displayed the distribution patterns clearly. Important findings The potential distributions of G. przewalskii with the highest environment suitability are predicted at first in the middle of Hexi corridor and the western Yumen of Gansu Province, the north of Ningxia-Hui Autonomous Region, and the part of the Wulate banner of Inner Mongolia in China. The others are mainly in northwestern Tarim Basin and small isolated areas in northwestern Qaidam Basin. Both MAXENT and GARP produced good predictions for G. przewalskii . However, GARP predicted larger and more continuous suitable habitats around the species’ locations and some isolated and fragmented spatial predictions where the species has never been found or collected before. MAXENT predicted a distribution that is a logical proportion of the study area and removed most of the unlikely isolated habitats.

利用野外调查的16个居群分布点和7个环境因子图层, 选择最大熵模型(MAXENT)和规则集遗传算法模型(GARP),在地理和环境空间上模拟了第三纪孑遗植物裸果木( Gymnocarpos przewalskii )在中国西北地区的潜在分布。结果表明: (1)裸果木的潜在适生区全部集中在西北荒漠区, 其中最佳适生区主要集中在3个区域, 一是河西走廊中部和玉门以西、宁夏北部及内蒙古乌拉特后旗; 二是塔里木盆地西北缘; 三是柴达木盆地西北缘两片极小的高度适生区。裸果木的生态位被确定在一个较广的干旱环境空间: 适生区极端最高气温基本上在29.2–36.8 ℃之间, 极端最低气温在–18.3至–13.4 ℃之间;年平均降水量40–200 mm; 潜在蒸发率在3–15之间。(2) MAXENT和GARP模型都较好地预测了裸果木的潜在分布, 但GARP产生了相对较大、较连续的潜在分布区, 部分过预测了破碎化生境; 而MAXENT预测到的潜在分布区, 在不同区域具有不同的环境适生性指数, 而且成功地排除了不合理的破碎化分布, 从而更直观地展示了裸果木的潜在分布格局和生态位要求。

With integration of literature data, specimens records, and field surveys, the current distribution map of  Schisandra chinensis  in China was drawn, and, based on this map and considering 21 environmental factors, the future distribution of S. chinensis  in China in the 2050s and 2080s under the IPCC A2 and A1B climate change scenarios was predicted by using Maxent software. Currently, the  S. chinensis  in China occurred in 15 provinces, involving 151 counties, and its distribution area decreased with decreasing latitude and longitude. The main distribution area included Heilongjiang, Liaoning, Inner Mongolia, and Jilin. The potential distribution area of S. chinensis  in China was 145.12×10 4 km 2 , 48.6% of which were the favorable habitat area, mainly distributed in Changbai Mountains, Xiaoxing’anling Mountains, Daxing’anling Mountains, and the regions between Hebei and Liaoning provinces. The most favorable habitat area only accounted for 0.3%, and was mainly in the Kuandian Manchu Autonomous County, Benxi Manchu Autonomous County, and Huanren Manchu Autonomous County of Liaoning Province, the Antu County and Helong County of Jilin Province, and the Yakeshi City of Inner Mongolia. U〖JP2〗nder the two climate change scenarios, the potential future distribution area of  S. chinensis in China would have a gradual decrease, and the decrement would be larger under A2 than under A1B scenario. By 2050, the distribution area of the  S. chinensis  under A1B and A2 scenarios would be moderately decreased to 84.0% and 81.5% of the current distribution area, respectively; by 2080, the distribution of  S. chinensis  under A2 scenario would be dramatically decreased to only 0.5% of the current range, and that under A1B scenario would be decreased to 1/2 of the current range.

结合文献资料、标本记录和实际调查绘制了中国五味子分布图，并基于五味子分布范围和21个环境因子，运用Maxent软件预测了IPCC A2和A1B两种气候变化情景下21世纪50和80年代中国五味子分布范围.结果表明： 五味子分布于中国15省/市（区），涉及151个县，随着纬度和经度的降低，面积逐渐减少，黑龙江、辽宁、内蒙古和吉林4省（区）是五味子主要分布区域；五味子在中国的潜在分布面积为145.12×10 4 km 2 ，较好生境面积占48.6%，主要分布在长白山山脉、大兴安岭、小兴安岭以及河北省与辽宁省相邻区域；最佳生境面积仅占0.3%，主要分布在辽宁省的宽甸满族自治县、本溪满族自治县、桓仁满族自治县以及吉林省的安图县、和龙市和内蒙古自治区牙克石市.在A1B和A2两种情景下，未来五味子潜在分布区逐渐减少，A2情景的五味子潜在分布区下降比率大于A1B情景；至21世纪50年代，A1B和A2情景下五味子潜在分布区将缩减为当前潜在分布区面积的84.0%和81.5%；至21世纪80年代，A2情景下五味子潜在分布区仅为当前的0.5%，B2情景下五味子潜在分布区减至当前的1/2.

基于影响植物功能型分布的6个气候变量:年均降水量、气温年较差、最冷月温度、最暖月温度、大于5℃积温和湿润指数,结合蒙古栎地理分布资料,根据最大熵 模型和各气候变量对蒙古栎地理分布的贡献,确定了影响蒙古栎地理分布的主导气候因子,即年均降水量、气温年较差、大于5℃积温和最暖月温度；利用模拟的蒙 古栎地理分布概率与主导气候因子的关系给出了各主导气候因子的阈值,即年均降水量330-910 mm、气温年较差大于29℃、大于5 ℃有效积温为1200-3500℃·d、最暖月温度为17-26℃.

The maximum entropy (MaxEnt) species distribution model combined with the existing geographic distribution record of alfalfa was employed in the present study. Ten variables correlated with growth of alfalfa ( Medicago sativa ) were selected for analysis which included 7 climate variables (annual precipitation, global radiation, temperature of the coldest month, mean annual temperature, the lowest temperature of green period, average temperature in August, air humidity in August) and 3 three soil variables (soil pH, soil thickness, soil organic matter content). The percent contribution of variables for alfalfa suitability and the dominant factors were calculated by Jackknife module of maximum entropy model. The results showed that AUC value of training data and test data were 0.913 and 0.889, respectively, which reached in “Accurate” level. Maximum entropy model can simulate the geographical distribution of alfalfa. The most suitable area( P ＞0.50) for alfalfa cultivation were 9.8×10 3 km 2 which mainly distributed in the south and southeast Xilin Gol and accounting for 7.7% of the total area. Meanwhile, our study also showed that the dominant factors affecting the geographic distribution of alfalfa were annual precipitation, temperature of the coldest month, the lowest temperature of green period, air humidity in August.

采用最大熵(MaxEnt)物种分布模型,结合紫花苜蓿( Medicago sativa )已有的地理分布记录,选取影响紫花苜蓿生长的10个变量,包括7个气候变量(年均降水量、年总辐射量、年最低温度、年均温度、5月最低温度、8月平均温度、8月空气湿度)和3个土壤变量(土壤pH、土壤厚度、土壤有机质含量)。采用最大熵模型的Jackknife检验,计算各变量对紫花苜蓿适宜性的重要性,筛选出影响紫花苜蓿适宜性分布的主导因子。结果表明,最大熵模型的训练子集和测试子集的AUC分别为0.913、0.889,均达到“很准确”水平,说明模型能准确地模拟紫花苜蓿在锡林郭勒盟的地理分布,紫花苜蓿的适宜种植区( P ＞0.50)主要分布于锡林郭勒盟南部和东南部,面积为0.98万km 2 ,占研究区总面积的7.7%。影响紫花苜蓿适宜性分布的主导因子为年均降水量、年最低温度、5月最低温度和8月湿度。

外来入侵植物假苍耳在中国东北部地区快速蔓延，威胁自然生态系统的结构并对人们的健康产生危害。本研究通过野外调查获得假苍耳在东北地区的分布范围，采用Ｍａｘｅｎｔ模型软件对假苍耳在我国及世界的潜在适生区进行预测，运用ＡｒｃＧＩＳ软件中的自然间断点分级法进行适生等级分类，ＲＯＣ 曲线评价Ｍａｘｅｎｔ模型预测的准确性，并结合刀切法及环境变量反应曲线判断分析影响假苍耳分布的主要环境变量。结果表明，假苍耳的适生区较广，扩散范围可能继续增大。我国的华北地区、东北地区、华东地区、华中地区、西南地区、西北地区均存在适生区，高度适生区主要分布在我国的黑龙江省、吉林省、辽宁省、内蒙古自治区、山西省、陕西省、河南省、河北省、山东省、北京市、天津市、新疆维吾尔族自治区。世界范围内除南极洲外均存在假苍耳的适生区，高度适生区主要在北美洲的加拿大和美国，非洲的摩洛哥，欧洲的西班牙、克罗地亚、匈牙利、斯洛伐克、波黑、塞尔维亚、马其顿、保加利亚、格鲁吉亚、亚美尼亚和阿塞拜疆，亚洲的土耳其、伊朗、哈萨克斯坦、吉尔吉斯斯坦、塔吉克斯坦、中国、朝鲜、韩国和日本。上述适生区预测显示出假苍耳适宜生长在年均温度较高，最冷月份最低温和最冷季度平均温度较低的中纬度地区。

Eupatorium adenophorum is one of the most invasive alien species in China. It has a strong ecological adaptability,and it can seize the niche very quickly thus the native species would be posed a threat to biodiversity by being crowded out. In order to study the potential distribution of E. adenophorum and its response to climate change,also to find out the environmental factors which influence the distribution of E. adenophorum ,the ecological niche factor analysis (ENFA) and the maximum entropy model were combined in this study. Firstly the environmental factors dimension was reduced by ENFA; secondly together with current and future climate data the study use MaxEnt model to predict the distribution of E. adenophorum in the future. The results showed that in the A1b scenario,the main distribution areas were Yunnan,Guizhou,and Guangxi province. From now to 2080s,the area of L 45 grade (the invasion probability is 0.6-1.0) was increased from 12.82 km 2 of nowadays to 21.30 km 2 in 2080s,and the center moved 46.62 km northwest. While the area of L 5 grade (the invasion probability is 0.8-1.0) was increased from 0.42 km 2 of nowadays to 0.91 km 2 in 2080s,and the center moved 178.66 km northeast. According to the research of the potential distribution of E. adenophorum in the current and future,the area of different invasion grade could be controlled by appropriate measures,and it will provide an important guidance for the comprehensive management.

紫茎泽兰的生态适应性强,是我国外来入侵物种中危害最为严重的恶性杂草。研究紫茎泽兰的适生性特征及对全球气候变化的响应规律是制定防控策略的重要基础,为此,本研究采用了将生态位因子分析(ENFA)与最大熵模型(MaxEnt)嵌套的方法,首先通过ENFA对环境因子进行降维,利用降维后的环境因子以及当前及A1b情景的未来气候数据,根据最大熵模型(MaxEnt)预测紫茎泽兰的潜在分布,并使用ROC曲线分析对预测结果进行评价。结果显示,当前气候情景下,紫茎泽兰的分布区以云南、贵州、广西等省为主;未来A1b情景下,易入侵等级(入侵概率为0.6~1.0)的区域面积将会由当前的12.82 km 2 增加至2080s的21.30 km 2 ,中心点将由当前位置向西南方向移动61 km;而其中高入侵概率等级(入侵概率为0.8~1.0)的区域面积将由当前的0.42 km 2 增加至2080s的0.91 km 2 , 中心点将由当前位置向东南方向移动178.66 km。根据当前及未来A1b气候情景下紫茎泽兰潜在分布情况,并根据不同入侵等级区域采取相应的防除治理措施,将对紫茎泽兰的综合治理具有重要指导意义。

Aims Our objective was to simulate and predict the impact of climate change on potential distribution in the relic and endangered Amygdalus mongolica , hence providing scientific basis for understanding the evolution and protection of this species. Methods Maximum entropy (MAXENT) model was employed to simulate, forecast, compare, analyze, and reveal the changes in the distribution range and spatial pattern in the relic and endangered A. mongolica at the Last Glacial Maximum (based on Community Climate System Model and the Model for Interdisciplinary Research on Climate), and under the historical (1961–1990) and future climate conditions (2020, 2050 and 2080, all based on the Intergovernmental Panel on Climate Change (IPCC) and Special Report on Emissions Scenarios A2A). The accuracy evaluation of repeat models of A. mongolica , and the average probability of occurrence and standard deviation based on repeat models were analyzed with the spatial analysis methods in the ArcGIS10.0. Important findings The potential distribution of A. mongolica under the historical climate conditions centered in Ömnögovǐ and Dornogovǐ of Mongolia, Bayannur City, Alxa Zuoqi, Ordos City, and western Xilin Gol Meng of Nei Mongol, the central and eastern regions of Hexi Corridor, the northern Ningxia and Shaanxi, and part of the northern Heibei. Furthermore, the distribution of A. mongolica at the Last Glacial Maximum based on Community Climate System Model climate scenario experienced the widely southward shift and range retraction. Last but not the least, under the future A2A climate scenario of IPCC, the potential distribution of A. mongolica would be significantly increased by 2020, and then decreased by 2050, with a slightly increasing trend until 2080. The distribution patterns of A. mongolica showed a large spread and shift to eastern Hebei and the eastern Nei Mongol of China, and to the eastern, northern, and western Mongolia.

为模拟、预测气候变化对孑遗、濒危植物蒙古扁桃( Amygdalus mongolica )潜在分布的影响, 利用最大熵(MAXENT)模型模拟、预测、对比、分析、揭示蒙古扁桃在最大冰期(CCSM及MIROC模型)、历史气候(1961–1990年)及未来气候(2020年、2050年和2080年, 政府间气候变化专门委员会排放情景特别报告的A2A情景)条件下的适宜分布范围和空间格局的变化。结果表明: (1)蒙古扁桃在历史气候条件下的潜在分布区集中在蒙古的南戈壁省及东戈壁省, 我国内蒙古巴彦淖尔市、阿拉善左旗、鄂尔多斯市、锡林郭勒盟西部, 河西走廊中部及东部, 宁夏北部及陕西北部, 以及河北北部的部分地区; (2)与历史气候条件下的潜在分布相比, 蒙古扁桃在最大冰期CCSM气候情景下的分布经历了明显的、大范围的向南迁移和范围缩小; (3)未来A2A气候情景下, 其潜在分布范围表现出在2020年明显扩大, 在2050年减小, 到2080年又略有增大的趋势。分布格局表现出不断向我国河北及内蒙古东部, 蒙古东部、北部及西部大幅度扩散、迁移的趋势。

Fritillaria cirrhosa D.Don(Liliaceae, Fritillaria L.) is a perennial herb possessing important medicinal properties in its dried bulbs. However, exhaustion of the wild resources of this species was seriously occurred in recent years. In this study, potential distribution prediction and suitability evaluation of F.cirrhosa were conducted and the main influential environmental factors were determined using 108 geographic occurrence records and 16 environmental variables based on Maxent modeling and GIS (ArcGIS 9.3). Our results showed that the potential distribution area of F.cirrhosa was mainly located in the southwest of Sichuan province, the northwest of Yunnan province and the southeast of Tibet. F.cirrhosa was also fragmentally distributed in the northwest of Guizhou province and the southwest of Gansu province. Within these areas, Sichuan (Liangshan Yi Autonomous Prefecture and Aba Tibetan and Qiang Autonomous Prefecture), Yunnan (Chuxiong Yi Autonomous Prefecture, Dali Bai Autonomous Prefecture and Diqing Tibetan Autonomous Prefecture), Tibet (the districts of Nyingchi, Shannan and Xigaze) were determined as the largest highly potential distribution areas (suitability index>0.5). The Maxent modeling showed that isothermality (contribution percent, 20.2%), annual average precipitation(16.6%), altitude(14.3%), standard deviation of temperature seasonal change(14.2%), minimum temperature of January(10.9%) and soil pH(7.9%) were the main influential environmental factors that affecting the distribution of F.cirrhosa . Further analysis of niche parameters demonstrated that F.cirrhosa prefers to grow in plateau areas with low annual range of temperature and high daily range of temperature and its suitable habitat requirements were altitude around 2 500-3 500 m, annual average precipitation around 850-905 mm, minimum temperature of January around -3.5-4.7℃ and faintly acid soil (pH around 6.66). The above results will provide valuable references for the wildlife tending, the plantation regionalization, and the standard cultivation of F.cirrhosa .

川贝母（ Fritillaria cirrhosa D.Don）为百合科（Liliaceae）贝母属（ Fritillaria L.)多年生草本植物，其干燥鳞茎为名贵中药材，具有重要的药用价值，但目前野生资源几近枯竭。本文结合川贝母108个地理分布记录和16项环境因子，应用最大熵模型（Maxent）和地理信息系统（ArcGIS 9.3），预测了川贝母在我国的潜在适生区及其适生等级。结果显示，川贝母的潜在适生区主要分布在四川的西南、云南的西北和西藏的东南等地区，贵州的西北和甘肃的西南部分地区有零星分布。其中，川贝母最适宜分布区集中在四川（凉山和阿坝）、云南（楚雄、大理和迪庆）和西藏（林芝、山南和日喀则）等地区(适生指数>0.5)。等温性（模拟贡献率，20.2%）、年均降水量（16.6%）、海拔（14.3%）、温度季节性变化的标准差（14.2%）、1月最低气温（10.9%）和土壤pH值（7.9%）是影响川贝母分布最主要的6个环境因子。综合分析表明，川贝母最适宜生长在年温差小而日温差大的高原或山区，海拔2 500~3 500 m、年均降水量为850~950 mm、1月份最低温度在-3.5~4.7℃和土壤偏酸性（pH=6.66）是川贝母最适宜生长的生态位参数。上述研究结果对于适生区开展川贝母野生抚育和种植区划及标准化栽培具有重要的指导意义。

Aims Our major objectives were to 1) identify keystone species within the context of functional groups, 2) develop potential distributional predict ions for keystone species using ecological niche model, 3) confirm factors determining potential distributions of keystone species, and 4) test if the performances of ecological niche model are better than those of a random model and differ in predicting different keystone species. Methods Based on the investigation of 135 plots in a natural tropical forest landscape, we classified woody plant functional groups based on successional status and potential maximum height. Keystone species within each functional group we re identified using a dominance index (DI). We used the genetic algorithm for rule-set prediction (GARP) to estimate the keystone species’ potential distribution and then used the receiver operating characteristics to evaluate predictive performance. Applying multiple linear regression analysis, we identified major factors determining potential distributions of keystone species. Important findings Identification of keystone species within pioneer species, climax shrub and emergent tree functional groups was clearer than within climax subcanopy and climax canopy tree functional groups. Generally, among the eight keystone species, pioneer species Melastoma sanquiueum , Aporosa chinensis and Liquidambar formosana (but not Adinandra hainanensis ) have high probability of occurrence in the north, west and southwest regions of Bawangling. However, climax species Psychotria rubra , Ardisia quinquegona and Castanopsis hainanensis (but not Pinus merkusii ) have high probability of occurrence in the central, southeast and south regions. Minimum and maximum temperature, mean annual temperature and precipitation, aspect and altitude were the key factors determining potential distributions of keystone species. Evaluation of GARP model’s performance indicated excellent predictive ability of all eight keystone species’ distribution. This study suggests the DI method is more suitable to identify keystone species with in woody plant functional groups in which a single or a few species are dominant. Findings will assist decision makers in planning conservation and management policies in tropical rainforest areas.

在较大的空间尺度上生态位模型是预测物种潜在分布的有效途径之一。为了探讨在热带天然林景观中木本植物（限于乔木和灌木）主要关键种 的潜在分布，在对海南岛霸王岭的热带天然林进行按公里网格样方调查的基础上，采用演替地位和最大潜在高度两个功能性指标对物种进行了 功能群划分，并在功能群框架下运用优势度指数法进行了关键种的确定；采用基于地理信息系统(Geographic information system, GIS)的基 于规则集合预测的遗传算法(Algorithm for rule-set prediction, GARP)生态位模型对主要关键种的地理分布进行了预测，并应用受试者工作 特征分析进行了模型精度验证；应用多元线性回归分析对影响各关键种潜在分布的关键因子 进行了确定。结果表明：除了顶极次林层乔木功能 群和顶极主林层乔木功能群外，在先锋种功能群、顶极灌木种功能群和顶极超冠层乔木功能群中采用优势度指数法划分出的关键种较为理想； 一般来讲，在进行预测的8个关键种中，除了先锋主林层乔木种海南杨桐（ Adinandra hainanensis ），其它3个先锋种毛稔( Melastoma sanquiueum )、银柴（ Aporosa chinensis ）和枫香( Liquidambar formosana ) 在研究区北部、西部以及西南部均具有较高的发生概率，而顶极 种除了顶极超冠层乔木种南亚松（ Pinus merkusii ）外，九节( Psychotria rubra )、高脚罗伞( Ardisia quinquegona )和海南椎（ Castanopsis hainanensis ）具有相似的潜在分布格局，在研究区中部、东南部和南部地区具有较高的发生概率；相关分析表明极端最低温、年均温、极端最 高温、年均降水量、海拔和坡向6大因子是影响研究区关键种潜在分布的关键因子；精度检验表明，GARP模型对8个关键种的潜在分布预测效果 均较好， 而其中又以银柴和海南椎的预测精度最高。

Mire, known as the ecosystems would be the most vulnerable to climate change, is widely distributed in the Northeastern (NE) China, and the NE China is one of the regions that would be mostly affected by the changing climates since the climate changes would mostly affect the area in higher latitudes. Therefore, studies of the spatial distributions of suitable habitats for mire in this region under future climate is obviously more important to conservation, restoration and mitigation among ecosystems, species distributions and climate changes. Based on the mire distribution data from the 1:4000000 Mire Map and 26 environmental factors in the NE China, the potential distributions of mire were predicted under the projected climate scenarios of current (1961-1990) and three future time-slices (2011-2040, 2041-2070, 2071-2100) through Maximum Entropy (MaxEnt) model as well as ArcGIS spatial analysis modules. The accuracy of predictions were accessed by the area under the curve (AUC) values of receiver operating characteristic (ROC) curve, and validation results showed that the predictions with MaxEnt model had a higher precision (mean AUC=0.826±0.005), and were credible and acceptable. The results for mire distribution showed that mire had a wide potential distribution range in the NE China, especially it mainly distributed in Great and Small Khingan Mountains and Sanjiang Plain under the current climate (based on the climate data from 1961-1990 years). However, the potential distribution area of mire decreased rapidly in NE China with changing climates since the new climate pattern would create new suitable habitat and make the currently suitable habitats would turn into unsuitable habitat for mire distribution, furthermore, the losing habitat rate was most higher than creating new habitat rate in this region under the changing climate. By 2011-2040 years, the current potential distribution area of mire reduced by 90.70%, the new suitable potential distribution area increased by 12.48%, the total potential distribution area of mire decreased by 78.22%. By 2041-2070 years, the current potential distribution area of mire reduced by 99.21%, the new suitable potential distribution area increased by only 3.23%, the total potential distribution area of mire decreased by 95.98%. By 2071-2100 years, the current potential distribution area of mire reduced by 99.80%, the new suitable potential distribution area increased by only 2.48%, the total potential distribution area of mire decreased 97.32%. As for spatial distribution, main distribution area of mire would shift from east part to west part at the longitude direction and shrink from the south and north part to central part of the region at latitude direction. By 2011-2040 years, the main potential distribution area of mire would shift to the northern part of Great Khingan Mountains, Songnen Plain, and Sanjiang Plain. By 2041-2070 years, the main potential distribution area of mire shifted to Hulunbeir Plateau, Songnen Plain, and Sanjiang Plain. By 2071-2100 years, the main potential distribution area of mire shifted to Hulunbeir Plateau and Songnen Plain. These results would provide important basis for making scientific management of mire and developing the measure for restoration mire and mitigating future climatic change in NE China.

东北地区是我国沼泽湿地分布最广泛的地区。为研究沼泽湿地对气候变化的响应,选取了对沼泽湿地分布可能存在影响的26个环境因子,利用最大熵(Maximum Entropy, MaxEnt)模型模拟了沼泽湿地基准气候条件下的潜在分布,并预测了气候变化情景下2011-2040 年、2041-2070 年和2071-2100 年3个研究阶段东北沼泽湿地潜在分布。研究结果表明:最大熵模型预测精度较高(平均AUC(Aera Under Curve)为(0.826±0.005))。基准气候条件下东北沼泽潜在分布区主要为大小兴安岭和三江平原地区。随着时间的推进,东北地区沼泽湿地原有潜在分布面积明显减少,而新增潜在分布面积较少,总面积呈现急剧减少趋势。至2071-2100年,原有沼泽湿地潜在分布面积将减少99.80%,新增潜在分布面积仅2.48%,总潜在分布面积减少97.32%。空间分布上,东北沼泽湿地潜在分布呈现由东向西迁移,南北向中心收缩的趋势。研究结果可为东北地区沼泽湿地保护政策的制定提供参考。

在我国河西走廊中部沙漠区,选择20年生以上C4荒漠植物梭梭(Haloxylon ammodendron)和沙拐枣(Calligonum mongolicum)植株,分干旱环境、雨后近地层空气湿润和人工树下挖坑浇水补充土壤水等3种水分条件,比较研究它们的光合作用特征.结果表明,在干旱环境下,梭梭和沙拐枣均表现出不同程度的强光下光合速率(Pn)下降现象,光系统Ⅱ光化学效率(Fv/Fm)明显降低,表现为光抑制.但在雨后空气湿润和人工浇水,使空气湿度和土壤湿度提高的条件下,2种植物的Pn日变化呈单峰型,Fv/Fm日变化小,没有光抑制现象.2种植物的Pn日平均值在雨后空气湿润条件下小于浇水后,浇水后第1天的Pn值明显高于第2天.水分条件改善后,梭梭和沙拐枣光合作用的光补偿点降低,光饱和点升高,光合速率对时间的积分加大.研究得出,水分胁迫导致C4荒漠植物梭梭和沙拐枣出现光抑制,提高空气湿度或者土壤湿度,都能避免光抑制,提高光能利用率.

The important values and the ShannonWiener indexes were analyzed based on carrying out a field investigation on sample plots of planted   [WTBX]Haloxylon ammodendron[WTBZ] communities in different sandy habitats in Minqin Oasis.The planted [WTBX]H.ammodendron[WTBZ] communities were classified into three types,i.e.,the [WTBX]H.ammodendron[WTBZ] (annual herbage) community,[WTBX]H.ammodendron[WTBZ] (annual herbage with shrubs) community and [WTBX]H.ammodendron[WTBZ]shrub community,and these communities were distributed on mobile sand dune,semifixed sand dune and fixed sand dune respectively.With the increase of sandfixed degree,the community succession was ranked from [WTBX]H.ammodendron[WTBZ] community (annual herbage,pioneer community with a coverage of 23% and ShannonWiener index of 0.26) to [WTBX]H.ammodendron[WTBZ] (annual herbage with shrubs with a coverage of 30% and ShannonWiener index of 0.34),and then to [WTBX]H.ammodendron[WTBZ]shrub community (with a coverage of 40% and ShannonWiener index of 0.60).In the succession,the growth of planted [WTBX]H.ammodendron[WTBZ] populations in different habitats was different,a recession of planted [WTBX]H.ammodendron[WTBZ] populations occurred from mobile sand dune to semifixed sand dune and then to fixed sand dune,and such recession was related to soil moisture content.

采用野外样方调查方法，分别对生长于民勤绿洲盆地不同立地类型的人工梭梭群落内的物种重要值、多样性等生态特征进行分析，将其划分为3个类型：梭梭—一年生植物群聚、梭梭—一年生植物—灌木群聚和梭梭—灌木群落；分别分布于流动沙丘、半固定沙丘和固定沙地上，随着沙地固定程度的增加，人工梭梭群落由梭梭—一年生植物群聚（先锋群落，盖度23%、多样性指数0.26）演替到梭梭—一年生植物—灌木群聚（盖度30%、多样性指数0.34）再演替到梭梭—灌木群落（盖度40%，多样性指数0.60）；在人工梭梭群落演替过程中，人工梭梭种群在不同沙地类型上生长状况不同，沿着流动沙地→半固定沙地→固定沙地为衰退型，这种衰退与土壤水分的含量有关。

Soil water contents at different depths(20 cm, 30 cm, 50 cm, 100 cm, 150 cm and 200 cm) were examined in planted Haloxylon ammodendron shrubland of different stand age(2-year, 5-year, 10-year, 20-year and 30-year) outside Minqin oasis from June to September, 2009. The results showed that soil water contents in H. ammodendron of different stand age were related to precipitation and soil depth. Soil water content at surface layer was affected by natural rainfall. In September, soil water contents at 20 cm and 30 cm in H. ammodendron of different stand age were significantly higher than that in other three months because of 25.8 mm rainfall in late August. Soil water content was relatively stable in deeper depths(>50 cm) and it can be used by H. ammodendron when surface soil water was absent in period with lower rainfall. In July and August, soil water content in planted 5-year H. ammodendron shrubland was the lowest(

2009年6月到9月,每月中旬在民勤绿洲边缘不同林龄(2 a,5 a,10 a,20 a,30 a)的人工梭梭林内测试不同深度(20 cm,30 cm,50 cm,100 cm,150 cm和200 cm)的土壤含水量变化情况。分析结果表明,不同林龄的梭梭林内土壤含水量与时间和深度有关。土壤表层含水量主要受自然降雨控制,8月底发生比较大的自然降雨后,9月不同林龄梭梭林内20 cm和30 cm的含水量显著高于其他3个月。土壤50 cm以下的含水量比较稳定,当降雨少,土壤表层含水量低时,可以作为梭梭利用的水分来源。在7月和8月,5 a梭梭林内土壤含水量最低,表明梭梭对土壤水分的消耗最多,栽植密度过大,因此,需要间伐减少植株数量才能维持其稳定性。

Based on a new published Vegetation Atlas of China and digitizing function of ARC/INFO GIS package, we produced a digital map to describe the actual distribution of Haloxylon plants dominated desert vegetation. The climatic requirements of Haloxylon species were extracted from the map subsequently using GREEN, a climate matching and mapping program for their potential distribution prediction. Compared between actual and potential distribution maps, the major factors that determine the potential distribution...

以我国最新出版的《中国植被图集》为基础,应用地理信息系统GIS软件ARC/ INFO(NT版)和数字化仪,提取以梭梭属植物为优势的现存荒漠植被地理分布信息,制作地理分布专题图;在生态信息系统(GREEN)软件支持下,定义地理气候适应参数区间,生成以梭梭属植物为优势的潜在荒漠植被分布图;将现存和潜在的分布图叠加并对照比较,揭示以梭梭属植物为优势的潜在荒漠植被分布特征,预测适宜以梭梭属植物为优势的荒漠植被发展的地理空间。结果表明:以梭梭柴为优势的潜在荒漠植被分布的行政区域包括新疆维吾尔自治区、内蒙古自治区、甘肃省、青海省等省(区) ,以白梭梭为优势的潜在荒漠植被分布的行政区域仅限于新疆维吾尔自治区;以梭梭柴为优势和以白梭梭为优势的潜在荒漠植被分布与现存的以梭梭柴为优势和以白梭梭为优势的荒漠植被分布的行政区域一致,分布的地貌也基本相同,但两者之间在地理分布边界和面积上存在较大差异。以梭梭柴为优势的潜在荒漠植被分布的北界超出现存的以梭梭柴为优势的荒漠植被的分布北界约0 .9个纬度,南界超出约0 .4个纬度;东界超出约5 .9个经度,西界超出约3.5个经度;以白梭梭为优势的潜在荒漠植被分布的北界超出现存的以白梭梭为优势的荒漠植被分布的北界约1个纬度；南界超出约0.9个纬度；东界超出约2.1个经度，西界超出约3.3个经度；全国现存的以梭梭柴为优势的荒漠植被分布的面积约占以梭梭柴为优势的潜在荒漠植被分布面积的9.1%。其中甘肃省现存以梭梭柴为优势的荒漠植被分布的面积约占该省以梭梭柴为优势的荒漠植被分布分布面积的5.6%，青海省约占该省的16.1%，内蒙古自治区约占该省的6.4%，新疆维吾尔自治区约占该省的10.5%。全国现存的以白梭梭为优势的荒漠植被分布面积约占以白梭梭为优势的潜在荒漠植被分布面积的34.1%。以梭梭植物为优势的潜在荒漠植被的预测结果可为梭梭荒漠植被的恢复和重建以及引种区划提供科学依据。

Specific information on geographic distribution of a species is important for its conservation. This study was conducted to determine the potential geographic distribution of , which is an endangered plant used in traditional Tibetan medicine, and to predict how climate change would affect its geographic range.The potential geographic distribution of under the current conditions in western China was simulated with MaxEnt software based on species presence data at 136 locations and 21 climatic variables. The future distributions of were also projected for the periods 2020s, 2050s and 2080s under the climate change scenarios of A1B, A2 and B1 described in the Special Report on Emissions Scenarios (SRES) of IPCC (Intergovernmental Panel on Climate Change).Results showed that mean temperature of the warmest quarter, annual precipitation, temperature seasonality, and isothermally were the four dominant climatic factors influencing the geographic distribution of . For the entire region of the seven provinces in western China, 11.71% of the areas were identified as suitable habitats, 15.86% as marginally suitable habitats, and 72.43% as, unsuitable habitats. The suitable habitats are mainly located in Sichuan, Gansu, Qinghai in the eastern edge of Qinghai-Xizang Plateau, and in areas with rich secondary vegetation and complex terrain in high altitudes. The model simulations indicated that the marginally suitable habitats would have a relatively small change under the climate change scenarios of SRES-A1B, SRES-A2 and SRES-B; whereas the suitable habitats would initially decrease by 2020s, followed by a trend of moderate increased thereafter. The average elevation of suitable habitats would be increased, and both the distributional range and the center of distribution would shift northward first, and then move west to the higher altitudes in mountainous areas of Qinghai-Xizang Plateau.

Ecological niche models (ENMs), which are widely employed to predict the potential geographic distribution of species, provide an important tool to quantify the risks imposed by invasive alien species. The problem of how to evaluate the performance of different models has attracted more and more attention. In the present paper, we introduced the principle of the method of Receiver Operating Characteristic (ROC) curve analysis in assessing the accuracy of different ENMs. We predicted the suitable distribution area of Radopholus similis , an important banana toppling disease nematode, with five widely used ENMs and evaluated the performance of different models by ROC curve analysis. The area under ROC curve (AUC) for BIOCLIM, CLIMEX, DOMAIN, GARP, and MAXENT models was 0.810, 0.758, 0.921, 0.903, and 0.950, respectively. Among these, the biggest value of AUC was assigned to MAXENT, indicating that the result gained by MAXENT should be better than the other four models. According to the results of analysis of variance (ANOVA), there was a remarkable difference in AUC between each model except for DOMAIN and GARP.

生态位模型(ecological niche models, ENMs)已广泛应用于物种潜在分布区预测, ENMs的应用也为外来入侵物种的风险分析提供了重要的定量化分析工具, 但如何评价不同模型之间的预测效果成了当今研究的热点问题。本文介绍了受试者工作特征(ROC)曲线分析在评价不同生态位模型预测效果中的应用原理和分析方法, 并以一种植物病原线虫—相似穿孔线虫( Radopholus similis )为例, 应用ROC曲线分析法对其5种模型(BIOCLIM, CLIMEX, DOMAIN, GARP, MAXENT)的预测结果进行了比较分析。5种模型的ROC曲线下面积AUC(Area Under Curve)值分别为0.810, 0.758, 0.921, 0.903和0.950, 以MAXENT模型的AUC值最大, 表明其预测效果最好; 方差分析结果表明, 除GARP与DOMAIN模型之间AUC值差异不显著外, 其余各模型之间差异显著。

通过对石羊河下游沙井子地区不同立地类型、不同林龄人工梭梭林的 大范围调查和定位观测研究,分析了主要生态因子降水、土壤水分和结皮对人工梭梭种群及其群落的影响.结果表明,梭梭对降水下限要求不严,但对降水上限有较 为严格的要求,180mm降水量是建立人工梭梭林的上限;石羊河流域现存人工梭梭林基本依靠降水生存,但非连续同向的年际降水波动变化,对人工梭梭种群无 明显影响,却显著影响梭梭林中草本植物物种组成、种群数量和生物产量.土壤水分是影响人工梭梭林最关键、最直接的生态因子,风沙土土壤含水率低于 0.824%,梭梭死亡,介于0.824%～1.30%之间,处于退化状态,高于1.30%,生长正常;土壤水分限制梭梭生长,而梭梭生长又会进一步加剧 土壤水分下降,梭梭造林8a后土壤含水率降低到1.30%,14a后降至土壤调萎系数之下,30a后又恢复到1.30%并保持稳定,残存梭梭种群生长趋于 正常.结皮在起到固沙和保护梭梭免遭风蚀的同时,明显限制水分下渗并引起土壤干旱,加速了人工梭梭林的退化,破坏结皮后土壤含水率逐渐增加;同时,结皮还 改变了1年生植物的种类组成及其数量.

Due to the current background of global climate change and heavy human activities, the precipitation and groundwater table on the southern edge of the Gurbantunggut desert have significantly changed, which could lead to variations in water use strategies of local plants. In our study, growth of the seedlings of Haloxylon ammodendron was investigated to reveal its growth traits and adaptability in the southern edge of Gurbantunggut desert. The results showed that the seedlings grew well from April to June when the soil water content was high, with the consumption of soil moisture, the above-and below-ground part of plant began to fall off, and then recovered growing in August. Mortality of seedlings showed a downward trend in the whole growth period. It suggested H. ammodendron seedlings could occupy more resource through rapid growth before the drought period, and falling of the assimilating branches in the drought period could maintain balance between water supply deficit and water consume of the assimilating organs. This morphological adjustment reduced seedlings mortality effectively. Also, more photosynthate was assigned toward root could ensure seedlings survival and recovered growth quickly at proper water conditions.

近几十年来，全球气候变化以及人类活动的加剧，导致古尔班通古特南缘荒漠地区的降水与地下水位发生显著的改变，这些改变必然导致荒漠植物用水策略的适应性变化。以古尔班通古特沙漠南缘原始沙漠中建群种梭梭的1年生幼苗为研究对象，对气象因子、土壤含水率、梭梭幼苗死亡率、地上地下高度（深度）、面积、生物量状况进行了全生长期的连续监测，以期探明1年生梭梭的生长、生存规律。结果表明：梭梭幼苗在土壤水分较为充沛的4-6月生长迅速，但随着土壤水分的消耗，7月地上地下部分都出现了不同程度的萎缩，在8月又恢复生长。在全年生长期中，幼苗死亡率基本呈现逐月下降的趋势。这说明在干旱来临前，梭梭幼苗快速生长以抢占更多资源；当遭遇干旱时，幼苗通过同化枝凋落有效的维持了根系供水与地上部分需水之间的平衡，保证了存活同化器官的光合能力，从而降低了死亡率。同时，幼苗以牺牲地上部分生长为代价将更多的光合产物转向根系，使得幼苗能够获得更多的水分保证其生长、生存。

Haloxylon ammodendron community in different natural stands conditions along southern edge of Zhunger Basin were studied on its structural characteristics, seedling supplies and age structures for investigating their own population patterns. The results showed that climate change led to, temperature varied sharply and the rainfall reduced in the early spring in arid area. As a result, a large number of H.ammodendron seedling dead. The age structure of H.ammodendron was commonly decreasing in different natural stand conditions along southern edge of Zhunger Basin for the lack of seedling-supply from climate change over the past decade. Microhabitats,the cover of soil or thin sand stratum could protect the seedling, and more H. ammodendron seedling survived. As a matter of fact, H. ammodendron age structures in these microhabitats were increase.

以新疆准噶尔盆地南缘的天然梭梭群落为研究对象，从群落组成、梭梭幼苗天然更新状况及梭梭种群年龄结构等方面，分析不同立地条件下梭梭群落的特征．结果显示：由于气候变化，3月下旬到4月初、春雨普遍偏少且雨日间隔较长，气温随之急速上升且呈强烈波动，导致浅土层迅速变干，引起初萌的植物幼苗大量夭亡，梭梭幼苗的正常补充机制因而受到严重威胁，导致准噶尔盆地南缘梭梭种群的年龄结构普遍呈现衰退，群落显现逆行演替特征。 观察表明，当地表存在稀疏的灌草和枯落层、或有适度沙层覆盖的龟裂土等类生境，仍较常见梭梭实生苗的存在，使此类局地梭梭幼苗补充机制得以维持，种群结构仍呈增长趋势。