Elephant Driven Changes in Riverine Tree Density Exacerbated by Biological Infestation in Samburu and Buffalo Springs...

African elephants (Loxodonta africana ) can profoundly impact the ecosystems in which they live and, therefore, are considered ecosystem engineers. Elephants break, push over, uproot, and de-bark woody plants, which can threaten the survival of some tree species. In this study, we investigated the changes in the composition, structure, and de-barking condition of riverine woodlands in the semi-arid Samburu and Buffalo Springs National Reserves of northern Kenya, over a 16-year period. Further, we assessed recruitment potential, the plant's response to debarking, and the subsequent disturbances by termites and woodborers. We conducted surveys of the woody plant community in nine 100 × 100 m riverine plots in 2007 and in 2023. All woody plants taller than 3 m with stem circumference over 6 cm were surveyed. Elephant debarking was assessed using a 0-5 scale: 0 (no debarking) to 5 (intensively debarked), based on the proportion of stem circumference debarked. We found that tree density declined between 2007 and 2023, with sapling density showing a marked reduction, indicating lower recruitment in 2023. Counts of trees across circumference classes differed between 2007 and 2023, with Vachellia elatior exhibiting a lower number of debarked individuals in 2023. Post-debarking tree recovery was significantly influenced by debarking severity, insect infestation, and stem decay. Termite presence on debarked trees reduced recovery likelihood, while woodborers had no measurable effect. Additionally, stem decay was associated with reduced tree recovery potential. These findings highlight the compounding impact of biological infestation with elephant debarking on tree survival. Understanding the interconnected effects of elephants and other organisms on plant communities is important to inform future habitat management and possible interventions for ecosystem restoration.