Most ferns in the world require abundant water to survive. However, ferns growing in southern California’s chaparral ecosystem experience a six-month summer drought every year. How have California ferns adapted to thrive despite limited water availability? My colleagues and I have assessed fern water use over the last decade and learned that these ferns have adapted a variety of strategies to survive the summer drought. Some ferns are evergreen, surviving the summer drought either by habitat selection (e.g., a perennial stream) or by extreme leaf dehydration tolerance. Other ferns experience summer dormancy, dropping dead leaves in the summer and growing new leaves after the first rain event. Perhaps most remarkable are the resurrection ferns, which can rehydrate (“resurrect”) apparently dead leaves when wetted. These different strategies likely reduce competition for water among fern species. Many questions remain about which ferns will best survive the challenges presented by climate change.

Dr. Helen Holmlund is an Assistant Professor of Biology at Pepperdine University. She earned her B.S. in Biology at Oklahoma Christian University and her Ph.D. in Ecology and Evolutionary Biology at the University of California, Santa Cruz. During her graduate work, she also spent a year training at the Australian National University. Her research in the field of plant physiological ecology explores how plants can survive drought, fire, and salinity. In particular, Dr. Holmlund is fascinated with ferns (which typically require abundant water) and how some ferns have adapted to thrive in dry ecosystems, such as the Santa Monica Mountains in southern California. Her research on these “extreme” ferns has also taken her to the Channel Islands, the mangrove swamps of Australia, and the tropical rainforests in Costa Rica.