Distribution of rainfall and Open Nahele plots (black dots) across three main islands of the Hawaiian archipelago studied here. The analysis including relatively uninvaded plots (i.e., < 40% individuals of alien species) is composed of 282 plots (Hawai‘i Island n = 190, Maui Nui n = 74 and O‘ahu Island n = 18). The analysis, including both uninvaded plots and highly invaded plots (> 40% individuals of alien species), is composed of 375 plots (Hawai‘i Island n = 254, Maui Nui n = 86 and O‘ahu Island n = 35). Rainfall units (mm) are based on mean annual precipitation i.e., mm/year. Island age approximation (Ma) corresponds to million years.