As Chief Conservation Officer for WCS, John is keenly interested in the sustainable use of natural resources and the relationship between conservation research and practice. After postdoctoral studies with the Smithsonian Institution, John was professor at the University of Florida, establishing a graduate program to train students from tropical countries.

John has over 180 publications including four books. Former president of the Society for Conservation Biology, board chair of the Christensen Fund and Foundations of Success, and on the executive committee of the Tropical Forest Foundation, he presently serves as IUCN councilor and vice president for North America and the Caribbean. King Bernhard of the Netherlands inducted John into the Royal Order of the Golden Ark, recognizing a lifetime of achievement and service to conservation.