His career as a plant ecologist has covered a wide range of interests: nature conservation, land-ocean interactions, application of mathematical models in ecology and conservation, and natural resource management in areas of traditional use. He is recognized for his studies on the interaction between climate variation and ecological dynamics, both in desert environments and in the context of land-sea interactions. He stands out for his important contributions to the political implications of the interconnections between the environment, ecology and people.
He was president of the National Institute of Ecology from 2001 to 2005, and has received accolades for his contributions to the field of ecology, including the Society for Conservation Biology's Conservation Biology Award in 1994, and the Pew Fellowship in Marine Conservation in 2006. He has published more than 170 research articles, books and book chapters, including three books on the Gulf of California and its islands, as well as numerous essays and articles for newspapers and popular magazines. As director of research at the San Diego Museum of Natural History, he developed the science script for the large format film Ocean Oasis, which won the Jackson Hole Nature Film Award in 2001, and the BBC Wildscreen Award in 2002, in addition to creating three successful museum exhibitions on the natural history of Baja California, Southern California and the Gulf of California.