Biogeographical parallels between plants and ants in North American deserts (Hymenoptera: Formicidae; Spermatophyta)

Water is the most limiting factor in deserts, yet researchers have very different emphases on the relative importance of water, depending on the organisms that they study. For example, soil moisture is considered the most critical factor for recruitment of desert succulent plants, and numerous studies have linked plant distribution patterns with soil texture, rainfall, and soil moisture. By comparison, ant biologists have neglected the importance of water and its affect on recruitment, population dynamics, and biogeography, probably because ant communities have been viewed as stable systems that are regulated by interactions among adult colonies. This paper argues that there are several similarities between desert plants and desert ants in regard to patterns of germination and recruitment, and that investigating and integrating these similarities will lead to better understanding population dynamics and biogeographic patterns of desert ants. Four similarities shared by these two groups of taxa include: (1) the trigger and timing of germination events, (2) early survival and establishment result from physiological tolerance, (3) propagule production and recruitment success vary across years, and (4) geographic variation in recruitment results from local and regional variation in soil moisture. Moreover, ant biologists would benefit from integrating the experiments, hypotheses, and approaches that plant biologists have used to understand population dynamics and geographic distribution patterns of desert succulent plants.