He studies ecological community assembly, with a focus on historical contingency, or when and why the structure and function of ecological communities are contingent on the past history of species immigration. This work involves various organisms, including the nectar-inhabiting microbes described here. He received a bachelor's degree from Waseda University, a master's degree from the University of Tokyo, and, in 2003, a Ph.D. from the University of Tennessee, Knoxville. After postdoctoral work at Landcare Research, New Zealand, he was an Assistant Professor at the University of Hawaii at Manoa before moving to Stanford in 2008.