中国特有种贯顶大帽藓西藏新分布及分布预测

New distribution and distribution prediction of the endemic species Encalypta asiatica J.C.Zhao&L.Li in Tibet,China

贯顶大帽藓(Encalypta asiatica J.C.Zhao&L.Li)为中国特有种,于2006年首次在河北发现,其后未见相关报道。本研究对2012-2020年期间在西藏采集的大帽藓科植物标本进行了整理和鉴定。通过形态结构的详细观察,新增了对蒴帽横切和气孔器等结构的描述,显示蒴帽横切由1~2层厚壁细胞和1~2层透明薄壁细胞构成;孢蒴表面从上到下密被气孔器。利用最大熵(MaxEnt)模型预测了贯顶大帽藓在当前气候情景下在西藏的潜在分布区,研究结果表明其潜在分布区面积约为2.84×10^(5)km^(2),主要分布于高海拔的那曲地区和昌都地区,影响其分布的主要环境变量是年最大归一化植被指数(NDVI)和最干季降水量。

Encalypta asiatica J.C.Zhao&L.Li,an endemic species of China,was first discovered in Hebei Province in 2006 and has not been reported since then.From 2012 to 2020,the bryophytes in Tibet have been investigated and collected by our research group and several specimens of E.asiatica were identified.In this paper,the morphological characteristics of E.asiatica were observed in detail.Transverse section of calyptra and capsule stoma were described for the first time:transverse section of calyptra is composed of 1-2 layers of thick-walled cells and 1-2 layers of transparent parenchymal cells;capsule surface is densely covered by stoma from top to bottom.MaxEnt model was used for analyzing the potential distribution of E.asiatica in Tibet under the current climate scenario.Results show that E.asiatica has a potential distribution area of 2.84×10^(5)km^(2),is mainly distributed in the high-altitude Nagqu and Qamdo,and the annual maximum NDVI(Normalized difference vegetation index)and precipitation of the driest quarter are the most important environment factors to determine its distribution.