Impact of drought-induced herbivory by Cape porcupine on Aloe claviflora on the Wolwekraal Nature Reserve, Prince Albert

Abstract

Aloe claviflora, widely distributed across the arid regions of southern Africa, remains understudied. In 2016, a population on the Wolwekraal Nature Reserve (113 ha) in the Western Cape, Succulent Karoo Biome, was surveyed to examine size class distribution and floral visitors. The genet population (205) had an inverse-J shape distribution with most genets occurring in the small size class (<0.5–1 m) and fewer occurring in the large size classes. The ramet population (1354), exhibited a typical bell-shaped distribution, with 77% of ramets in 2016 occurring in the reproductive size class. In 2016 and 2021, 33% and 29% of the population produced flowers, respectively, which were visited by birds, reptiles, honeybees, solitary bees, and small mammals. Persistent drought (2015–2021) halted flowering in 2019 and 2020. Browsing by Cape Porcupine was first observed in 2018. Therefore, subsequent surveys conducted in 2019 and 2021 assessed the extent of damage. Since 2016, 62.9% of genets and 39.7% of ramets were destroyed. The data suggest that the animals frequently browsed on reproductive ramets. This study highlights the impact of drought-induced porcupine browsing on A. claviflora survival, underscoring significant changes in porcupine behavior and the resulting population decline of this long-lived, arid-adapted species.