A Comparison of Lichen Biodiversity of Teatown Lake Reservation and Bronx River Parkway By: Madeline Bohan, Nora Fodero, Sophiana Simone Juliette Thomas Lichen is a composite organism, made up of a fungus partner and an alga or cyanobacterium. Both parts of the composite organism receive water and mineral nutrients mainly from the atmosphere. Lichens play a crucial role in the ecosystems that they grow in. Lichens are sensitive to air pollutants, in particular, to sulfur dioxide (SO2) and nitrogen dioxide (NO2). Sensitivity of lichens to pollution even led to an idea that lichens can serve as an indicator of air quality. Our goal is to compare the biodiversity of lichen species from Teatown Lake Reservation (TLR) and from Bronx River Parkway (BRP). We predict that lichen biodiversity will be greater in TLR as compared to BRP.