Twice a year for the last 29 years, scientists have waded through the same sections of tallgrass prairie in eastern Kansas and tallied up as many plant species as they could find. The goal was to determine the impact of American bison and cattle on the ecosystem, compared with plots of similar prairie protected from these grazers. 

It’s hot, tedious, and tick-infested work, but it is incredibly important: Tallgrass prairies used to cover a huge portion of Texas and stretch all the way up to southern Canada. Today this habitat, dominated by head- and waist-high grasses and forbs, herbaceous flowering plants, is imperiled. Tallgrass prairie is now present in just four