Location of the study area and the 200 1-ha plots in the Chemehuevi Valley, Sonoran Desert, California, USA. To avoid illegal take of desert tortoises, we did not provide detailed locations (latitude, longitude) in figures. Havasu Lake is part of the Colorado River. Chemehuevi Wash, a major axial valley, ephemeral stream channel, drained into the Colorado River. A power-line corridor, two wells, a mine, and multiple four-wheel vehicle routes were present. The northeast corner of the study area was ∼1.6 km from the community of Havasu Lake and is on the Chemehuevi Reservation.