The long-term decline of a succulent tree, Aloidendron pillansii, in the hyper-arid Richtersveld region of southern Africa

Aloidendron pillansii, a Critically Endangered succulent tree in the Richtersveld Cultural and Botanical Landscape, faces severe population decline due to dual pressures: recent droughts disproportionately kill juveniles, while aging adult cohorts contribute to long-term losses. Between 2012 and 2024, juvenile numbers plummeted by 51%, largely driven by extreme drought (2017–2019) and human disturbance, whereas adult declines accelerated after 1937, reflecting senescence. Range-wide analysis reveals older populations in the north and younger ones in the south, with Cornell's Kop showing intermediate aging. Climate trends since 1979—declining rainfall, longer dry seasons, rising temperatures, and reduced vegetation productivity—threaten recovery. The study combines repeat photography, ecological monitoring, simulation modeling, and climate analysis to demonstrate how climate change and human activity are exacerbating the species' decline.

Hoffman, M. T., Carrick, P. J., Cramer, M. D., Swart, E., van Blerk, J. J., & van der Merwe, H. (2026). The long-term decline of a succulent tree, Aloidendron pillansii, in the hyper-arid Richtersveld region of southern Africa. Journal of Arid Environments, 234, 105571. https://doi.org/10.1016/j.jaridenv.2026.105571