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 (I suspect by approximately 30% for many genera).
Currently, a major focus of my research on this topic is centered on Colombia, which is the most fern-rich country in the Americas. Alejandra Vasco, Michael Sundue, and I 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
From 2020-2022, I was a postdoc in the Antonelli Lab at the University of Gothenburg, in Sweden. The principal project I worked on there integrates herbarium specimen data and modeling approaches to identify imperiled plant taxa and areas of conservation priority, focusing on the island of Hispaniola, which includes Haiti and the Dominican Republic. I was drawn to this island because it 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 combines several of my favorite research topics - natural history collections, biodiversity informatics, the Greater Antilles, and endemic species. In addition, this work is rewarding because it has the potential to aid conservation of this imperiled flora.
Land plant phylogenomics
From 2018-2020 I was a postdoc on the Genealogy of Flagellate Plants (GoFlag) project at the University of Florida, which is funded under the NSF's "Genealogy of Life" program. We have generated a comprehensive phylogeny of the flagellate plants: mosses, hornworts, liverworts, lycophytes, ferns and gymnosperms. To accomplish this, we are generating 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.
An important aspect of this project is the level of collaboration that it has promoted. The basic model of data acquisition for the GoFlag project is that collaborators from around the world send us plant material from their study groups, we generate sequence data from those samples, and the resulting data is shared with those collaborators (cost-free!), who get access to the data for a period of time before the data go public. This project has included more than 100 collaborators from institutions around the world.
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.