Taiwan Pteridophyte group

Diversity of Taiwanese Pteridophytes

Islands are hotspots for pteridophyte (ferns and lycophytes) biodiversity, harboring over 76% of the species in less than 5% land mass in the world. Pteridophytes of Taiwan display an extraordinarily high diversity that, in terms of species number, represents one of the top five most species-rich insular floras in the world, and also the highest one among East Asian archipelagos. To better understand biodiversity of these plants, we (leading by L.-Y. Kuo and other TPG members here) are incorporating their biological information from various aspects. In the first step, an updated checklist has been generated which aims to clarify phylogenetic and “nomenclatural” diversity (see more details in the TPG list here and TPG google discussion group). The next steps are going to cover more additional information, particularly about their current distribution, genetic diversity (e.g. DNA barcodes), ploid level, and reproductive mode. Basic understanding of the endemic or rare pteridophytes will also inform future conservation policies and actions.

On the another side of studying origin of insular biodiversity, understanding extinction risks for island species is equally important. Disappearance of an endemic species on island means its global extinction. In particular, under the trends of climate change, neo-endemic species on geographically young islands are facing extremely high risk of extinction due to their young evolutionary ages with narrowly adopted habitats. The Taiwan endemic pteridophytes hence become our prior foci to study their diversity in many aspects. Based on our recent survey, one third of the 88 Taiwan endemic pteridophyte species is currently risked, and five of them are threatened. Critically, near a quarter of these pteridophytes still exposes to an unevaluated degree of extinction because of poor biological understanding. Our primary mission is to study the biology of Taiwan endemic pteridophytes much deeply, first, the reconfirmation of their taxonomic and current population statuses. In the followings, surveys of ecological niche, investigations of the genetic diversity, and studies of other biological aspects (e.g. reproduction) will be made. Importantly, using niche modeling approach to project future population range and gathering other data from studies of basic biology, we are going to assess impacts of climate changes on the sustention of field populations of Taiwan endemic pteridophytes.

 

臺灣蕨類植物多樣性

全世界島嶼佔了總陸地面積不到5%，但卻擁有76%的蕨類植物(含蕨類與石松類)種類，可說是蕨類植物多樣性的熱點。就種數而言，臺灣的蕨類植物具有極高度的多樣性：在全世界島嶼蕨類豐富度中排名第五，也是東亞諸島蕨類豐富度最高的地方。為更深入瞭解這群植物的多樣性，我們(郭立園博士及其他TPG成員主持)整合了各方面的生物資訊：首先我們更新了臺灣的蕨類植物名錄，以釐清其演化系統及分歧的使用名稱(詳TPG名錄及TPG論壇)；接著我們將進行更多面向的探討，包括現生族群分布、遺傳多樣性(例如生命條碼)、倍體性、及生殖模式等。此外，特有性與稀有種的探究瞭解，也將進一步提供未來保育策略與行動的重要參考依據。

關注島嶼的生物多樣性起源的另一面－島嶼物種的滅絕風險是生物學家同樣重視的議題，一個島嶼上特有種的消失，就等同於這個物種的滅絕。尤其是地質年輕島嶼上的新特有物種，因為演化歷史較短、分布局限，只具狹隘的環境適應能力，成為氣候變遷下的高滅絕風險類群。因此臺灣特有種成為計劃中的首要研究的蕨類植物。根據我們最新的調查，在已知臺灣特有的蕨類植物88種當中就有超過三分之一有滅絕風險、五種受到威脅，但還有近四分之一的物種因基礎資料不足尚無法評估、暴露在未知程度的風險中。更深入蒐集這些物種的基礎生物學資料，特別是分類地位的再確認和現今族群分布，是我們當前的研究任務。接續的研究工作還包含這些臺灣特有的蕨類植物生態棲位調查、基因多樣性的初探以及其他基礎生物資料的收集(如生殖生物學)。更重要的是，能透過生態棲位的研究來提供這些特有物種的未來分布預測模型，同時考慮他們基礎生物資料來評估氣候變遷對這些特有物種野外存續之影響。

 

Systematics and Reticulate Evolution of Asian ferns

Asia is one of most fern rich georegion in the world, and harbors several important hotspots. We have studied fern genera highly diversified in Asia with particular foci on vittarioids (leading by C.-W. Chen), Deparia, Dryopteris subg. Nothoparanema, Stegnogramma s.l., Lomariopsidaceae (leading by L.-Y. Kuo), Pteris, and Bolbitis (leading by Y.-S. Chao). By revealing their phylogenies and morphological characterization, we aim to provide systematic insights and taxonomic revisions for these ferns, including description of novel taxa. On these bases, we are trying to better inform diversification and local speciation processes of these Asian ferns.

In many fern species complexes, like Pteris fauriei (leading by Y.-S. Chao), Deparia tomitaroana, Adiantum philippense (leading by L.-Y. Kuo), reticulate evolution has occurred usually, including polyploidization and hybridization, and given rise to taxa with similar or continuously varied morphology. Such confusions from appearance are primary causes of their problematic taxonomy. Multidisciplinary approaches are used to tackle such problems, and cover methodologies in order to study phylogeny, cytology, and reproductive mode of these ferns. In the case of P. fauriei complex, climatic niche modeling is also conducted to infer ecological niche preference of different cytotaxa.

亞洲蕨類植物的系統分類與網狀演化

亞洲具有許多重要的生物熱點，也是世界蕨類高豐富度的地理區之一。我們已經進行亞洲許多蕨類科屬的研究，特別是書帶蕨類群(陳正為主持)、對囊蕨屬、鱗毛蕨屬-肉刺蕨亞屬、溪邊蕨屬、蘿蔓藤蕨科(郭立園主持)、鳳尾蕨屬、實蕨屬(趙怡姍主持)；藉著親緣關係的分析與形態觀察比較，提供演化系統與分類訂正的依據，同時也進行新種的發表與描述。以此為基礎，以瞭解亞洲蕨類植物在各地的歧異度與種化過程。

許多蕨類植物的複合種群，例如傅氏鳳尾蕨(趙怡姍主持)、羽葉對囊蕨、菲律賓鐵線蕨(郭立園主持)等，經常發生多倍體化及雜交，而形成網狀演化，也使得各分類群具有高度相似性及連續性變異的形態。這些外觀也造成了分類問題的困擾。我們使用多種研究方法，包括親緣關係、細胞學、生殖模式等以釐清這些問題。以傅氏鳳尾蕨為例，氣候區位模式也同時用來推測各倍體群對不同生態區位的喜好性。

Fern phenology

Ferns belong to the largest lineage among vascular non-flowering plants. Because of lacking flower, “crypto” phenology of ferns has been long neglected. Poor knowledge about fern phenology makes natural life history of these plant still mysterious, and has impeded a deep understanding of their ecology and life history evolution. It has not been fully studied how ferns survive, reproduce, regenerate, and complete a life cycle in their nature habitats. Particularly, when these plants allocate their energy starting to produce reproductive organs including their fertile leaves and spores? More importantly, what kind of environmental factors initiate this developmental process? Fern phenology havs been surveyed in around 225 species previously, but this number presents about only 2% of the total species in the world. To acuminate our understanding in this field, we (leading by Y.-M. Huang) are continuously investigating phenology of fern species in Taiwan, and have long-term observation for more than 40 species. Broad-scale research, multi-disciplinary approach, and quantitative methods have been applied, and provide promising directions to shed light on fern phenology.

 

蕨類植物物候學

蕨類植物是不開花維管束植物中最大的一個系群。由於沒有花，其物候現象也不易察覺而長期被忽略。這種蕨類物候知識的匱乏，使得我們對其生態與演化難以深入了解，也增添了本群植物自然生活史的神秘感。這些有關蕨類植物的生存、生殖、繁殖及其在自然界的生活史一直都沒受到詳細的調查與研究；特別是這些植物如何分配其能量以啟動像生殖葉與孢子等生殖器官的發生，以及環境因子如何影響這些發育的進行。全世界對於蕨類物候學的研究約進行了225種植物的調查，而這只佔了全球蕨類植物總數的2%。為增加對蕨類物候方面的了解，本團隊(黃曜謀博士主持)以長期、跨區域及量化數據的方法，持續進行40餘種臺灣蕨類植物的物候現象研究，結果也提供了我們對蕨類物候學瞭解的新視野。

 

 

ONGOING PROJECTS

Phylogenomics, Systematics, and epiphytism evolution of Lomariopsidaceae (MOST Grant Number 109-2621-B-007-001-MY3; 2020.1-2022.7 hosted by L.-Y. Kuo)

ABSTRACT Lomariopsidaceae is one of the few fern families that has experienced drastic changes in their generic composition, which still remains unsettled. In addition to Lomariopsis, the most diversified (~60 spp.) and hemiepiphytic genus in this family, the currently recognized Lomariopsidaceae includes four other smaller genera (1-7 spp.), Cyclopeltis, Dracoglossum, Dryopolystichum, and Thysanosoria, which are mostly terrestrial. However, the phylogenetic relationships among these genera and also that between sister Polypodiineae families are unresolved. It is still a debate whether or not Nephrolepidaceae needs to be placed within Lomariopsidaceae. To resolve relationships among these genera and families and ascertain their systematic positions, this projectaims to conduct a sampling covering >95% species diversity of Lomariopsidaceae and generate a phylogenomic dataset. Based on a well resolved backbone, I will infer the evolution of several epiphyte-associated traits, particularly the long-lived gametophytes and (cryto)chlorophyllous spores. These results will provide another important case to study the evolution of epiphytism in ferns. In addition, my preliminary data already reveal several cryptic species within Lomariopsis. Together the Lomariopsis independent gametophytes that still with a mysterious identity, these phylogenomic results will provide new insights into systematics within this genus, and, combining with morphological characters, aim to finally propose a new infra-generic frame for Lomariopsis.

摘要 蘿蔓藤蕨科是蕨類植物系統分類變動大的科之一，至今尚未完全確定其科之分類範圍。蘿蔓藤蕨科中除了近60種且半附生的蘿蔓藤蕨屬，其他屬類群僅有1-7個物種且絕多數為地生，包括擬貫眾蕨屬、Dracoglossum、Dryopolystichum與Thysanosoria。然而這些類群的屬間親緣關係還有蘿蔓藤蕨科在水龍骨目中的系統分類位置仍尚未釐清，水龍骨目中之腎蕨科是否要合併至蘿蔓藤蕨科還具備爭議。為了解決這些科間與屬間的親緣關係，本研究計畫將針對蘿蔓藤蕨科進行更完整的取樣將涵蓋>95%物種，由此取樣得到一個高解析度的親緣基因體序列矩陣。基於高支持度的演化關係骨架，將更進一步探討與附生有關的配子體世代性狀，包括(隱蔽性)綠色孢子與長命配子體，其演化歷史是否與蘿蔓藤蕨科中半附生演化有關。除此之外，初步的研究資料已指出許多隱蔽物種存在於蘿蔓藤蕨屬之下，所以本研究計畫將一併探討這些隱蔽物種與獨立配子體物種他們的分類地位，並配合形態資料最後提出一個新的蘿蔓藤蕨屬的屬下分類架構。