The southward advance of native African farmers with Central African crops halted in Natal, beyond which Central African crops couldn't grow - with enormous consequences for the recent history of South Africa.

F. 2005 Collapse: How Societies Choose to Fail or Succeed. PMID 3762700.

Originally trained in physiology Diamond's work is known for drawing from a variety of fields including anthropology ecology geography and evolutionary biology. He is currently Professor of Geography at the University of California Los Angeles.