Relationship between site characteristics and relative richness change: (A) the absence/presence of surface water; (B) management unit [Death Valley National Park (DEVA), Joshua Tree National Park (JOTR), and Mojave National Preserve (MOJA)]; (C) ... Relationship between site characteristics and relative richness change: (A) the absence/presence of surface water; (B) management unit [Death Valley National Park (DEVA), Joshua Tree National Park (JOTR), and Mojave National Preserve (MOJA)]; (C) elevation (m); and (D) latitude. Error bars and shading represent 95% confidence intervals. Kelly J. Iknayan, and Steven R. Beissinger PNAS 2018;115:34:8597-8602 ©2018 by National Academy of Sciences