Lichen Walk

Focusing Attention on Microscopic Ecologies Amidst Environmental Change Comprised of algae, fungi, and other organisms, lichen are place-rooted symbiotic communities that can emerge in the crevices of tree bark, along the surfaces of rocks, on trash can lids in parking lots, and in other unexpected places. Lichen complicate boundaries between species, modes of reproduction, and life and mortality. These complex communities are highly sensitive to air pollution, and for many years, their abundance declined across New York City. Activism against urban air pollution has helped protect public health by mitigating air emissions from transportation and other activities relative to levels prior to the 1970s. Along with these human health benefits, over the past 50 years, lichen have made their way back to New York City, flourishing with improved conditions. In this parking lot walk, we will use magnifying lenses, microscopes, and other tools to draw our attention to lichen in our surroundings. Following a brief introduction to lichen ecology, we’ll discuss their role as an indicator species of air quality change in our own city. Together we’ll consider lichen as complex microbial communities that inhabit surprising urban spaces and record collective environmental memories.