Identification of Fern Gametophytes using DNA Barcodes
Fern gametophytes, as the sexual phase of the fern lifecycle, are critically important to fern biology. However, due to their small size and simple morphology, the field ecology of fern gametophytes has for the most part been literally overlooked. I am developing methods that use short diagnostic DNA sequences, or “barcodes” to identify fern gametophytes so that they can be more easily studied in the field.
One central question in biology is, “why do certain species tend to live together?” I am interested in how fern species interact to form communities. I investigate this using recently developed community phylogenetic methods, which take into account the evolutionary history of species when modeling community assembly processes. I am currently surveying the fern communities of two tropical sites, Moorea (French Polynesia) and Nectandra (Costa Rica).
One of my favorite fern families is Hymenophyllaceae, or “filmy ferns.” These ferns get their name from their extremely thin leaves, which are only a single cell layer thick between the veins. This thinness is actually an adaptation that allows filmy ferns to quickly absorb water across the entire leaf surface. They typically occur in moist areas in the tropics, and appear to the casual observer to be very fragile and sensitive to humidity. However, many species can actually tolerate periods of drought, and seemingly “come back to life” when it rains again! I study the evolution of different growth forms and adaptations to drought in both the gametophytes and sporophytes of filmy ferns.