Peter Kareiva is chief scientist at the Nature Conservancy. Previously, he spent 20 years as a university professor and three years working on salmon conservation for the National Oceanic and Atmospheric Administration Fisheries. His past research has concerned mathematical biology, fisheries science, insect ecology, genetically engineered organisms, population viability analysis, agricultural and landscape ecology, and global climate change. His current scientific research focuses on evaluating conservation strategies and studying the everyday choices we make about nature’s assets and ecosystem services.