Profile of Daniel H. Janzen.

When Daniel Janzen gave his acceptance speech for the 1997 Kyoto Prize, he disappointed many people who had come to hear a preeminent biologist discuss iconic studies, from ant–acacia mutualism to seed predation (1, 2). “They expected a talk about science, but I’d switched to conservation,” explains Janzen, DiMaura Professor of Conservation Biology at the University of Pennsylvania. Janzen, who was elected to the National Academy of Sciences in 1992, and his wife, tropical ecologist Winnie Hallwachs, have spent 35 years reframing the idea of national parks into that of collaboration between forests and societies. “The biology is easy, but we have to study society,” explains Janzen. “Forme, it’s all human ecology.” Together with thousands of partners, they have developed and expanded Area de Conservación Guanacaste (ACG) in Costa Rica into 168,000 ha of land and sea that, Janzen notes, protect 2.6% of the world’s biodiversity, and are now using DNA barcoding technology to create a library of species (3).