Joshua Tewksbury is the director of the Smithsonian Tropical Research Institute (STRI), a unit of the Smithsonian Institution headquartered in Panama City, Panama.

Tewksbury was born in California, and he grew up living on US farms. He received a bachelor’s degree from Prescott College (US) in 1992 and a PhD from the University of Montana (US) in 2000. He did postdoctoral work at the University of Florida.

As an ecologist, evolutionary biologist and conservation biologist, Tewksbury addressed fundamental questions during over 20 years of active field research in the US and Latin America: How does climate impact plants and animals? How do fragmentation, connectivity, invasive species and mutualism loss affect populations and communities? How did plant chemical defenses evolve?

Tewksbury was the Maggie and Doug Walker Endowed Professor of Natural History at the University of Washington (US), with appointments both in the Department of Biology and the College of the Environment, which he helped to create. He has held faculty positions at the University of Colorado Boulder, Colorado State University, and George Mason University. Tewksbury launched and directed the Luc Hoffmann Institute, a global research center in Geneva, Switzerland, and directed the Colorado global hub of Future Earth. He is the founder of Anthropocene magazine. He led two NOMIS research projects: the Future Earth Program for Early-Phase Grants Advancing Sustainability Science and Future Earth PEGASuS 2—Ocean Sustainability. In 2021, Tewksbury was named director of the Smithsonian Tropical Research Institute, which has been a NOMIS partner since 2024.