[2][3] Harrison switched to ecology for her graduate studies, and earned a master's degree in 1986.
[2] Harrison joined Stanford University for her doctoral studies, completing her PhD in biology in 1989.
[4] Her doctoral work considered the Edith's checkerspot butterfly and was supervised by Paul R. Ehrlich and Richard Karban.
[5][6][7][8] After her PhD, Harrison was a postdoctoral fellow at Imperial College London, where she worked at Silwood Park.
Harrison demonstrated that the formation of metapopulations is more complicated; and can be patchy, non-equilibrium and geographical.
[15] She has studied the native plant species in the serpentine soils of California with Brian Anacker.