Neotropical fern & lycophyte diversity
The American tropics are one of the most biologically diverse places on earth, and this holds true for pteridophytes as well: more than 1/3 of the world's fern and lycophyte species are found in the Neotropics. A large and growing number of studies have examined why this region harbors so many species of organisms (and ferns, in particular); however, that species diversity itself remains understudied. This is evident when working in herbaria with large collections of Neotropical ferns and lycophytes - more often than not, species folders are filled with specimens that can be sorted out into 2, 3, or more groups. The reality is that taxonomists have not captured the diversity in these groups - there simply are too many taxa waiting to be described and not enough data to confidently separate them.
Unlike the situation in temperate regions, where ploidy levels, reproductive mode, and often DNA sequences of most fern and lycophyte species have been systematically evaluated by botanists over the past century, little to nothing is known about most of their Neotropical counterparts beyond their morphology. Given the prevalence of reticulate evolution in ferns -resolving hybrid complexes nearly doubled the number of fern taxa recognized in the Flora of North America- filling in these gaps for the ferns of tropical America should go a long way toward improving species circumscriptions and will push the number of species recognized in the region even higher in the years to come!
Currently, a major focus of research on this topic is centered on Colombia, which is the most fern-rich country in the Americas. Alejandra Vasco, Michael Sundue, and Wes received a $1.1 million grant from the National Science Foundation to support our study of fern diversity in Colombia. This project, which is titled "PurSUiT: Collaborative Research: Accelerating Lineage Discovery to Document Neotropical Fern Diversity" will run from 2021-2025 and includes extensive field work, development of genomic resources, collections-based research, and student training. As always, close collaboration with local colleagues is a central part of this project, and we are excited to be back in Colombia!
Predicting extinction risks of an imperiled island flora
Hispaniola is the second largest island in the Caribbean and harbors a rich flora with a large number of rare and endemic species that are acutely threatened by habitat loss and other factors. Recent studies have shown that the Haitian side of the island is nearly completely deforested, and the habitat loss on the Dominican side is accelerating - simply put, the island is in the midst of a mass extinction event that could result in the loss of hundreds or even thousands of plant species. This project, which we are carrying out in collaboration with partners at the Jardín Botánico de Santo Domingo, University of Florida, and Haiti National Trust, combines natural history collections, biodiversity informatics, the Greater Antilles, and endemic species. is rewarding because it has the potential to aid conservation of this imperiled flora.
Land plant phylogenomics
The Genealogy of Flagellate Plants (GoFlag) project has generated a comprehensive phylogeny of the flagellate plants: mosses, hornworts, liverworts, lycophytes, ferns and gymnosperms. To date, we have generated sequence data from about 450 nuclear loci for ~8000 of the ~30,000 taxa in these clades using a targeted sequencing approach. Beyond resolving relationships among major land plant lineages, we are very interested in understanding the evolution of key innovations in the land plant Tree of Life and are linking our phylogenomic dataset with data on functional traits, species distributions, and the fossil record.
This project also has a significant educational component, and we are collaborating with pedagogy experts to develop online educational tools to promote learning about flagellate plants, from elementary school to universities. Some of these modules are already in use, and others are currently in development!
You can access our pilot paper here.