Lawrence R. Walker is a Professor of Plant Ecology at the University of Nevada, Las Vegas. He received his Ph.D. in 1985 from the University of Alaska, Fairbanks. His research focuses on the mechanisms that drive plant succession, particularly primary succession on volcanoes, landslides, glacial moraines, floodplains, dunes, mine tailings and abandoned roads. He has co-written or co-edited four books on disturbance ecology, succession and restoration, published over 100 peer-reviewed papers, and is an ISI Highly Cited Researcher with over 2500 peer citations of his work. Walker received a Fulbright Award in 2004 for work in Iceland and has received three Distinguished Researcher awards from the University of Nevada. In 2009-10 he was the Wilder Chair in Botany at the University of Hawaii at Manoa.

Joanne M. Sharpe is an independent consultant specializing in fern ecology, long-term studies, the role of amateurs in ecological research, and education. She received her Ph.D. in Botany at the University of Georgia in 1988. She is currently a Research Associate with the NSF-funded Luquillo Long Term Ecological Research (LTER) program in Puerto Rico where for the past 18 years she has monitored fern growth and spore production as part of rainforest productivity, hurricane impact and demographic research projects. She has published 10 articles and presented interim results at numerous professional meetings. She compiles the Annual Review of Pteridological Research for the International Association of Pteridologists and manages their membership database thus maintaining contact with pteridologists throughout the world.