蓑藓属( Macromitrium)和木灵藓属( Orthotrichum)是木灵藓科( Orthotrichaceae)的两个最大的属,前者呈现泛热带分布式样,后者呈偏温带性分布式样。应用当前和基于RCP4.5( Medium-Low Representative Concentration Pathways)二氧化碳排放情景下2050和2070的11个生物气候变量,以及木灵藓属( Orthotrichum)66个、蓑藓属( Macromitrium)131个国内分布记录,应用最大熵模型( MaxEnt),预测了气候变暖背景下这两属植物在我国38个自然保护区潜在分布范围的变化。11个生物气候变量包括昼夜温差月均值、年温度变化范围、温度季节变化、最热月份最高温、最干季度平均温度和最冷季度平均温度、最湿月份雨量、最干月份雨量、雨量变化方差和最暖季度平均雨量。选择了10%的遗漏错误对应的累积值作为分布预测阈值,为了更好地展示气候变化下这两个属的潜在分布区变化,选择了我国境内的38个自然保护区并计算了不同气候条件下两种藓类植物属在这些自然保护区的综合气候适应指数。38个自然保护区包括福建武夷山、甘肃祁连山、广东南岭、广西花坪、广西十万大山、贵州梵净山、贵州雷公山、海南尖峰岭、河北五台山、河南鸡公山、河南小秦岭、湖北神农架、湖北星斗山、吉林长白山、江西庐山、辽宁白石砬子、辽宁医巫闾山、内蒙古大黑山、宁夏贺兰山、青海三江源、山东云台山、山西历山、山西芦芽山、陕西佛坪、陕西太白山、四川贡嘎山、四川卧龙、云南哀牢山、云南大围山、云南纳板河、浙江凤阳山、浙江古田山、浙江九龙山、浙江普陀山、浙江清凉峰、浙江天目山、浙江乌岩岭和重庆大巴山。结果表明,随着气候变暖,蓑藓属和木灵藓属在我国的适生面积都将减少,蓑藓属植物在我国的潜在分布区面积从当前的31.5%下降到12.23%,木灵藓属的从当前的65.81%下降到44.94%,气候变化对蓑藓属植物分布的影响要大于木灵藓属。对于蓑藓属植物,当前气候条件下的38个自然保护区中,除了宁夏贺兰山和甘肃祁连山外,其他的36个保护区都有适合于蓑藓属植物分布的气候条件。到了2070,河南鸡公山、山东云台山、浙江普陀山、浙江九龙山、浙江古田山、内蒙古大黑山、山西芦芽山、江西庐山、辽宁医巫闾山、广西花坪、辽宁白石砬子、河北五台山、山西历山、河南小秦岭、陕西佛坪、吉林长白山、贵州梵净山、贵州雷公山和福建武夷山这19个自然保护区不再或几乎不再适合于蓑藓属的分布。对于木灵藓属植物,在当前的气候条件下,38个自然保护区中,除了海南尖峰岭保护区,其余的37个保护区均处于木灵藓属植物潜在分布范围之内。与当前气候条件相比,2070年38个保护区的气候条件均变得不利于木灵藓属分布,其中广西花坪、江西庐山、云南纳板河、广西十万大山、河南鸡公山、山东云台山、浙江普陀山、浙江天目山、浙江古田山、浙江九龙山、福建武夷山、贵州梵净山、辽宁医巫闾山、河南小秦岭和陕西佛坪等15个保护区已不在木灵藓属的潜在分布范围。%Macromitrium and Orthotrichum are two largest genera in the Orthotrichaceae ( Bryopsida) family. Macromitrium are distributed across tropical zones, while Orthotrichum are distributed throughout temperate zones. Based on eleven bioclimatic variables modeled under recent ( 1950—2000 ) , 2050, and 2070 RCP45CO2 emission scenarios, 66 geographical records of Orthotrichum, and 131 records of Macromitrium in China, this paper used the algorithm of maximum entropy ( Maxent ) to predict the potential Chinese distributions of these two genera in 2050 and 2070. The eleven bioclimatic variables are:mean diurnal temperature range;temperature seasonality;annual temperature range;the highest temperature of the warmest month;mean temperatures of the driest quarter and coldest quarter;precipitations of the wettest month, driest month, warmest quarter, and coldest quarter;and precipitation seasonality. Thirty-eight nature reserves were selected and an integrated climate suitability index was calculated for each of them under different climate conditions. These 38 reserves are: Wuyishan ( Fujian ); Qilianshan ( Gansu ); Nanling ( Guangdong ); Huaping and Shiwandashan ( Guangxi);Fanjingshan and Leigongshan ( Guizhou ); Jianfengling ( Hainan ); Wutaishan ( Hebei ); Jigongshan and Xiaoqinling ( Henan);Shennongjia and Xingdoushan ( Hubei);Changbaishan ( Jilin); Lushan ( Jiangxi); Baishilizi and Yiwulvshan ( Liaoning ); Daheishan ( Inner Mongolia ); Helanshan ( Ningxia ); Sanjiangyuan ( Qinghai ); Yuntaishan (Shandong);Lishan, Luyashan, Foping, and Taibaishan (Shaanxi); Gonggashan and Wolong (Sichuan); Ailaoshan, Daweishan, and Nabanhe ( Yunnan);Fengyangshan, Gutianshan, Jiulongshan, Putuoshan, Qingliangfeng, Xitianmushan, and Wuyanling ( Zhejiang);and Dabashan ( Chongqing) . The corresponding cumulative value for an omission error of 10%was selected as a distribution threshold. The primary results were:(1) The suitable bioclimatic habitats for Macromitrium and Orthotrichum would shrink considerably with predicted climate warming. The potential distribution range of Macromitrium in China would declime from 31.5% under recent climate condition to 12.23% under 2070 climate condition, while that of Orthotrichum would declime from 65.81% to 44.94%. The negative effects of climatic warming on the potential distribution would be greater for Macromitrium than for Orthotrichum;(2) All of the nature reserves, except for Helanshan and Qilianshan, had suitable niches for Macromitrium under the recent climatic scenario. Under the 2070 predicted climate scenario, the potential distribution of Macromitrium would not include Jigongshan, Yuntaishan, Putuoshan, Jiulongshan, Gutianshan, Daheishan, Luyashan, Lushan, Yiwulvshan, Huaping, Baishilazi, Wutai, Lishan, Xiaoqinling, Foping, Changbaishan, Fanjingshan, Leigongshan, and Wuyishan (half of the 38 nature reserves in this study);and (3) All of the nature Reserves, except Jianfengling, had suitable niches for Orthotrichum under the recent climate scenario. By 2070, the weather adaptation indices for Orthotrichum in all of the 38 reserves would be lower than those under the current conditions. According to our predictions for 2070, Orthotrichum would be excluded from the reserves in Huaping, Lushan, Shiwandashan, Jigongshan, Taishan, Putuoshan, Xitianmushan, Gutianshan, Jiulongshan, Wuyishan, Fanjingshan, Yiwulvshan, Xiaoqinlingshan, and Foping.
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