African aloe ecology: A review

Aloe L., is the largest genus in the Asphodelaceae, a family of succulent-leaved, petaloid monocots, geographically restricted to the Old World. Aloes exhibit remarkable morphological variability and range in size from dwarf species only a few centimetres tall, to tree aloes reaching heights of up to 20 m. Aloes form a striking and important component of many arid and semi-arid African landscapes. Most Aloe species occur in arid savanna, which is widespread over subtropical southern and eastern Africa. In southern Africa, aloes receive considerable interest from both scientists and succulent plant enthusiasts. World-renowned for their medicinal properties, aloes are used in numerous natural products traded in the health and cosmetic industries. There is a wealth of popular literature on the genus, as well as various scientific publications, although these have tended to focus on aloe pollination biology and medicinal use. Knowledge on aloe ecology is vital for the management and conservation of wild populations as well as the arid and semi-arid lands in which they occur. Sound ecological understanding of the genus is also important for making decisions regarding sustainable utilization, as well as predictions relating to possible threats posed by climate change. Furthermore, by better understanding the genus, its utility in practical applications such as ecosystem restoration can be explored further. Hence, this review provides a synthesis of a wide range of available information on several aspects of aloe ecology, and highlights important opportunities for future research. The key aspects covered include aloe distribution, ecophysiology, functional role in the ecosystem, population dynamics, fire tolerance, resprouting, pollination ecology, seed biology, economic botany and conservation.