The Chinese water pine Glyptostrobus pensilis is the sole surviving species of the genus Glyptostrobus. It is endemic to southern China, central Vietnam, and eastern Laos, and today it is nearly extinct in the wild. F...The Chinese water pine Glyptostrobus pensilis is the sole surviving species of the genus Glyptostrobus. It is endemic to southern China, central Vietnam, and eastern Laos, and today it is nearly extinct in the wild. Forest community characteristics and population structure of G. pensilis in China have remained un-known up to now. We investigated six swamp forest stands and analyzed their forest community characteristics (i.e. vertical stratification, species composition, and diversity) and population structure, including the frequency distribution of DBH (diameter at breast height) and age-classes as found in Fujian Province, southeastern China. The vertical stratifications of all the forest stands were rather simple. The remaining wild specimens ranged from roughly 15 to some 357 years for an average of ca. 85 years, with only a few individuals less than 20 years old. Compared with the stands and populations of G. pensilis in Vietnam, the taxonomic compositions of the stands in the two regions were different, except for the dominant species-G. pensilis. The Shannon-Wiener index showed the overstory of each stand had much lower diversity (0.26 on average) in Fujian Province than that (1.97 on average) in Vietnam, whereas the diversity indices were about the same (around 2.41) for the understories in the two regions. Furthermore, we discovered 18 G. pensilis seedlings at the study sites in Fujian Province. This discovery demonstrates that G. pensilis regeneration is extremely poor and its populations are declining, although these populations are rela-tively healthier than those in Vietnam.展开更多
以孑遗植物银杉(Cathaya argyrophylla Chun et Kuang)为研究对象,选取65个地理分布记录和19个生物气候因子(bio1—bio19),利用MaxEnt模型预测四种不同浓度路径下(RCP 2.6、RCP 4.5、RCP 6.0和RCP 8.5),银杉在2050s和2070s两个年代的潜...以孑遗植物银杉(Cathaya argyrophylla Chun et Kuang)为研究对象,选取65个地理分布记录和19个生物气候因子(bio1—bio19),利用MaxEnt模型预测四种不同浓度路径下(RCP 2.6、RCP 4.5、RCP 6.0和RCP 8.5),银杉在2050s和2070s两个年代的潜在分布变化,并利用景观指数对气候变化情景下银杉适宜生境空间格局特征转变及生境破碎度变化进行分析。结果表明:在当前气候情景下,银杉适宜生境面积约占研究区面积的14.32%,主要分布于北纬24°—32°、东经105°—114°之间,位于四川盆地东南地区、云贵高原东北地区、南岭西段地区以及浙闽丘陵的北部地区。在未来不同气候情景下,银杉适宜生境变化特征显著,面积呈增加趋势,形状上整体呈四周向中间聚集。气候变化对银杉适宜生境的景观指数影响主要表现在斑块数量增多、斑块密度增加、面积加权平均形状指数变大,对分离度与聚散性影响较小;气候变化对银杉生境破碎化程度的影响表现在破碎化两极现象减弱,总体破碎化程度加剧。研究选取7个景观指数并结合PCA法得到综合的破碎度指数来定量分析银杉适宜生境破碎化程度变化,相比单一指标的定量评价和多个指标的定性分析,更能代表银杉生境的实际破碎化程度。展开更多
基金funding by the National Natural Science Foundation of China (31760152 and 31500355)the Key National Research and Development Plan Program of China (2016YFC050310203)+1 种基金the Natural Science Foundation Project of CQ CSTC, China (cstc2016jcyj A0379)the National Program on Space Science and Technology, Vietnam Academy of Science and Technology, Vietnam (project VT-UD.09/18-20)
文摘The Chinese water pine Glyptostrobus pensilis is the sole surviving species of the genus Glyptostrobus. It is endemic to southern China, central Vietnam, and eastern Laos, and today it is nearly extinct in the wild. Forest community characteristics and population structure of G. pensilis in China have remained un-known up to now. We investigated six swamp forest stands and analyzed their forest community characteristics (i.e. vertical stratification, species composition, and diversity) and population structure, including the frequency distribution of DBH (diameter at breast height) and age-classes as found in Fujian Province, southeastern China. The vertical stratifications of all the forest stands were rather simple. The remaining wild specimens ranged from roughly 15 to some 357 years for an average of ca. 85 years, with only a few individuals less than 20 years old. Compared with the stands and populations of G. pensilis in Vietnam, the taxonomic compositions of the stands in the two regions were different, except for the dominant species-G. pensilis. The Shannon-Wiener index showed the overstory of each stand had much lower diversity (0.26 on average) in Fujian Province than that (1.97 on average) in Vietnam, whereas the diversity indices were about the same (around 2.41) for the understories in the two regions. Furthermore, we discovered 18 G. pensilis seedlings at the study sites in Fujian Province. This discovery demonstrates that G. pensilis regeneration is extremely poor and its populations are declining, although these populations are rela-tively healthier than those in Vietnam.
文摘以孑遗植物银杉(Cathaya argyrophylla Chun et Kuang)为研究对象,选取65个地理分布记录和19个生物气候因子(bio1—bio19),利用MaxEnt模型预测四种不同浓度路径下(RCP 2.6、RCP 4.5、RCP 6.0和RCP 8.5),银杉在2050s和2070s两个年代的潜在分布变化,并利用景观指数对气候变化情景下银杉适宜生境空间格局特征转变及生境破碎度变化进行分析。结果表明:在当前气候情景下,银杉适宜生境面积约占研究区面积的14.32%,主要分布于北纬24°—32°、东经105°—114°之间,位于四川盆地东南地区、云贵高原东北地区、南岭西段地区以及浙闽丘陵的北部地区。在未来不同气候情景下,银杉适宜生境变化特征显著,面积呈增加趋势,形状上整体呈四周向中间聚集。气候变化对银杉适宜生境的景观指数影响主要表现在斑块数量增多、斑块密度增加、面积加权平均形状指数变大,对分离度与聚散性影响较小;气候变化对银杉生境破碎化程度的影响表现在破碎化两极现象减弱,总体破碎化程度加剧。研究选取7个景观指数并结合PCA法得到综合的破碎度指数来定量分析银杉适宜生境破碎化程度变化,相比单一指标的定量评价和多个指标的定性分析,更能代表银杉生境的实际破碎化程度。
