2016/11/01 by Harald Schneider, Eric Schuettpelz · 1 citation
Agricultural and Biological Sciences · #Fern and Epiphyte Biology #Plant Diversity and Evolution #Plant Parasitism and Resistance #Fern #Context (archaeology) #Systematics #Biology #Evolutionary biology #Sister #Ecology #Paleontology #Sociology #Taxonomy (biology) #Anthropology
paper · pdf · doi:10.1111/jse.12231
openalex publication_date 2016/11/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Welcome to this special issue of the Journal of Systematics and Evolution focused on the systematics and evolution of lycophytes and ferns. It is our hope that it will inspire innovative research on these plants at this critical time where human activities are transforming biodiversity as we know it. Lycophytes and ferns are distinct evolutionary lineages, with ferns strongly supported as sister to seed plants and lycophytes, in turn, sister to this large (euphyllophyte) clade. Notably, however, lycophytes and ferns do share many features, including vascular plant apomorphies (e.g., vascular tissue) and land plant plesiomorphies (e.g., spore dispersal and the absence of seeds). For these reasons, they have long been collectively treated as “pteridophytes” and it still seems appropriate to address the biology of both lineages together. This special issue was initiated in the context of the most recent international scientific meeting dedicated to ferns and lycophytes, Next Generation Pteridology, which was organized by Eric Schuettpelz and colleagues in 2015. Although it is not designed as the proceedings of that meeting, the theme of “next generation” is maintained by including a diverse array of early-career contributors (along with those who are well-established) and by focusing on a selection of topics for which data are coming from novel sources enabling innovative research. These topics may challenge long held hypotheses or support emerging new hypotheses. Of course, this special issue cannot cover all aspects of lycophyte and fern biology, and recent more-comprehensive compilations already exist (e.g., Ranker & Haufler, 2008; Mehltreter et al., 2010). Here, we aim to give attention to contributions that will hopefully be relevant to the research of the future generations of pteridologists. Topics were selected to cover a wide range of issues, including some that may, at first blush, appear a bit old fashioned. At the same time, some readers may be surprised by the absence of contributions in some frequently highlighted fields, but some outstanding reviews have already been published in areas such lycophyte and fern genomics (e.g., Sessa & Der, 2016). All contributions to this special issue share a common theme of aiming to document and understand lycophyte and fern diversity. Such documentation arguably requires the ability to classify these plants and we are pleased to publish here the first installation of a new approach to the classification of lycophytes and ferns from the Pteridophyte Phylogeny Group (PPG I, 2016). The initiative towards the establishment of the Pteridophyte Phylogeny Group was inspired, but not constrained, by the successes of the Angiosperm Phylogeny Group. It involved an open call to anyone working on the systematics of lycophytes and ferns, with the aim to establish a community-based classification. The result required considerable compromise and is quite distinct from existing classifications. Diversity is also the focus of a critical review of our current understanding of fern and lycophyte systematics in the Neotropics (Almeida & Salino, 2016). Although this region has been intensively studied by many prominent pteridologists, including John Mickel, Robbin Moran, Alan Smith, and Rolla Tryon, major gaps in our knowledge remain (e.g., under-sampled regions and lineages requiring taxonomic revisions). This review also highlights the need to study these ferns within a broader framework (i.e., beyond national floras). A similar message is given in another contribution, which explores the distinct pteridophyte flora of the East African Biodiversity Hotspot (Liu et al., 2016). This latter study was enabled by the outstanding contributions of many pteridologists who explored Africa, culminating in the work by Jacobous “Koos” Roux (2009), and further emphasizes the need to identify and address gaps in our knowledge concerning the distribution and taxonomy of pteridophytes, in both species-rich and species-poor regions. Interestingly, these two contributions to this special issue also serve to collectively highlight an interesting shift in the study of tropical floras away from the historical powerhouses of botany based in North America and Europe. Links between evolutionary and ecological processes are at the core of the research on elevational diversity patterns summarized by Kessler et al. (2016). This study provides an outstanding example of the power that can be achieved by integrating observations of local diversity gradients into a global hypothesis. A somewhat more local perspective is provided by focusing on the pteridophyte diversity of Hawai'i (Ranker, 2016). Oceanic islands are known to have exceptionally high proportions of pteridophyte diversity (Kreft et al., 2010), but are also widely recognized as “evolutionary laboratories” in which to explore the accumulation of biodiversity. The Hawai'ian islands are unique in combining geographic isolation with extensive habitats that are suitable for ferns and lycophytes. Future studies may attempt to compare this oceanic archipelago with other islands that are rich in pteridophyte diversity, such as the Mascarene Islands (Hennequin et al., 2014) and to employ pteridophyte diversity as an indicator for the impact of climate change on the biodiversity on oceanic islands with high-elevations (Pouteau et al., 2016). Two contributors to this special issue were willing to assemble perspectives on topics closely associated with a pair of the most influential pteridologists of the mid-20th-century: Irene Manton and Edward Klekowski. The two reviews explore state-of-the-art of research on hybridization (Sigel, 2016) and apomictic reproduction (Grusz, 2016). Both reviews comprehensively summarize our current understanding and point out promising research directions that take advantage of new genomic tools (the access to genomic data has historically been one of the main limitations of research on these topics). Progress in our understanding of these aspects of pteridophyte biology has always been closely linked to the establishment of new methods, as well as the careful application of groundbreaking concepts (Haufler, 2014). The combination of old and new approaches will likely also lead to a renaissance in our understanding of the interactions of lycophytes and ferns with other organisms. Pressel et al. (2016) provide a critical look at pteridophyte-fungal associations that is inspired by the authors' research on these associations across all seed-free land plants. Fungal associations, including mycorrhizal associations, have been studied for a long time, but, as the authors carefully document, many key aspects are still in need of clarification. This contribution will hopefully inspire similar critical investigations into other associations with pteridophytes, such as that of phytophagous insects utilizing ferns as their core food supply (Schneider, 2016). Much like fern-fungus associations, fern-insect associations have been long-studied but careful exploration of existing evidence, combined with new evidence, will certainly lead to additional insights (Schneider, 2016). A final contribution to this issue is provided by Brummitt et al. (2016), who provide an important look to the current threats to pteridophyte diversity, as assessed using IUCN Red List criteria. This is the first comprehensive analysis of available data for these plants, and covers about 8% of extant pteridophyte diversity. The results of this study may be interpreted as evidence supporting the hypothesis that pteridophyte diversity will experience a major decline in coming decades. In this context, the subsequent analyses defining spatial aspects of the threats to pteridophyte diversity will hopefully encourage pteridologists to examine changes in diversity focusing on both global threats (as in Brummitt et al., 2016) and local changes (Pouteau et al., 2016). Progress may not only require further inventories of fern and lycophyte diversity (see Almeida & Salino, 2016; Liu et al., 2016) but also the integration of different types of evidence to obtain reliable predictions based on understanding ecological-evolutionary processes (Kessler et al. 2016), the impact of interactions (Pressel et al., 2016), and the role of reproductive biology (Bystriakova et al., 2014). We hope that this special issue will inspire pteridologists to consider their contributions to ongoing efforts to protect the diversity of these plants within established frameworks to conserve plant diversity (Corlett, 2016). In closing, we would like to express our gratitude to the Editors-in-Chief, Song Ge and Jun Wen, of the Journal of Systematics and Evolution for providing us with the opportunity to compile this special issue and we also want to express our thanks for all the patience and support provided by the editorial team, especially by Yan Liang. And, of course, we want to thank all of the contributing authors, whose inspiring efforts enabled us to assemble this special issue that demonstrates the diversity of expertise in a truly global community carrying out research on ferns and lycophytes. Harald Schneider Institute of Ecology and Evolution, School of Life Sciences, Sun Yat-Sen University & Department of Life Sciences, Natural History Museum, London Eric Schuettpelz Department of Botany, National Museum of Natural History, Smithsonian Institution