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.






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.




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.







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、DracoglossumDryopolystichumThysanosoria。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。