中国喀斯特洞穴维管植物多样性

Cataloguing vascular plant diversity of karst caves in China

洞穴是喀斯特景观中普遍存在的地质地貌结构,拥有丰富的植物资源。仅2001–2020年间,就发表了中国喀斯特洞穴维管植物新属1个;新种(含种下等级)170个,隶属于16科31属,占近20年发表的中国维管植物新种的3.9%,说明洞穴植物具有较高的物种多样性潜力。据统计,中国喀斯特洞穴维管植物有110科339属871种,主要分布于广西、广东、贵州、云南、重庆等地。物种数排名前5的科包括苦苣苔科、荨麻科、鳞毛蕨科、秋海棠科和茜草科,其所含物种数共占整个洞穴植物种类的39.4%;排名前5的属包括报春苣苔属(Primulina)、楼梯草属(Elatostema)、耳蕨属(Polystichum)、秋海棠属(Begonia)和凤尾蕨属(Pteris),其所含物种数共占整个洞穴植物种类的25.1%。本名录的所有洞穴植物中,草本习性的种类占一半以上。从洞内分布来看,仅有10.7%的种类分布于弱光带,其中石松类和蕨类植物占比远高于被子植物,说明前者更能适应弱光带的极端环境。不仅如此,洞穴维管植物也具有较高的特有性成分,其中省级特有种占比25.8%,分别包括非洞穴特有种(11.0%)、多洞穴特有种(3.3%)和单洞穴特有种(11.5%)。依据文献显示受威胁种类有115种(占13.0%)。受威胁种类占比较高的类群均是近年来发表新种较多的科,包括鳞毛蕨科、苦苣苔科、荨麻科、秋海棠科、茜草科等。针对这些类群,有待更详细地调查来完善对它们的评估。此外,本名录中至少有36%的种类没有任何分子数据,亟待补充。

Aim:Caves are widespread geological structures within karst landscapes which is associated with diverse flora.In the last 20 years,dozens of new species from Chinese caves have been described,many of which are not in the current list of the Chinese cave flora.In this study,we aimed to generate an updated list of China’s cave flora to better reflect the species diversity and endemism of the ecosystem and raise attention to its importance for the conservation and sustainable use of biological diversity.Methods:We created a catalogue of all the Chinese cave plants by integrating the published regional lists of cave plants and reviewing the publications describing newly discovered species from Chinese caves.We utilized this information to generate an updated list of China’s cave flora of vascular plants.All accepted names were retained while the repetitive and unidentified names were eliminated based on the database of Plants of the World Online(POWO).The characteristics of the cave flora,the species distribution within caves,and the IUCN status of each species’were analyzed.Results:From 2001 to 2020,one new genus and 170 new species(including infraspecific taxa)belonging to 31 genera and 16 families(APG IV and PPG I classifications)of vascular plants were described from karst caves in China.We documented 871 species belonging to 339 genera and 110 families of vascular plants from the karst caves mainly in the provinces of Chongqing,Guangdong,Guangxi,Guizhou,and Yunnan.The five most common families identified in caves were Gesneriaceae,Urticaceae,Dryopteridaceae,Begoniaceae,and Rubiaceae,accounting for 39.4%of the total cave plant species.The five most commonly identified genera were Primulina,Elatostema,Polystichum,Begonia,and Pteris,accounting for 25.1%of species diversity.Herbaceous species constitute over half of the cave flora,and 10.7%of species occupy the twilight zone.In comparison with angiosperms,the proportion of lycophytes and ferns in the twilight zone was higher,suggesting that they adapt easier to the extreme habitats of twilight zones.Furthermore,there were high levels of endemism of vascular plants in caves.There were 225 provincial endemic species,accounting for 25.8%of the total cave plant species.Among these,the proportions of non-cave endemism,multiple cave endemism,and single cave endemism were 11.0%,3.3%and 11.5%,respectively.A total of 115 species(13.0%)were under threat of extinction according to the literature review.The most threatened families were those with newer species published in recent years,including Dryopteridaceae,Gesneriaceae,Urticaceae,Begoniaceae,and Rubiaceae.More detailed investigations should be conducted to refine the IUCN assessments of these taxa.In addition,molecular data are lacking for at least 36%of the species in our list.Conclusions:Our updated list suggests that caves are important for species discovery in China.Further investigations in caves are needed,particularly in Yunnan,Chongqing,and Hunan.We propose that most cave plant species probably originated from the karst forest understory and are therefore of great significance for the restoration of native karst vegetation and the combatting of desertification.For this reason,China’s cave flora should be further documented and protected.