Bush Encroachment and Large Carnivore Predation Success in African Landscapes: A Review

Abstract

Bush encroachment is a habitat change phenomenon that threatens savanna and grassland ecosystems worldwide. In Africa, large carnivores in bush encroached landscapes must adjust to increasing woody plant cover and biomass, which could affect predation success at multiple stages through complex and context-dependent pathways. We highlight, interpret, and compare studies that assessed how bush encroachment or related habitat parameters affect the predation stages of large African carnivores. Bush encroachment may directly or indirectly affect predation success in various ways, including by: (1) altering habitat structure, which may affect hunting efficiency and prey accessibility; (2) changing prey abundance/distribution, with smaller species and browsers being potentially favoured; (3) influencing interference competition within the carnivore guild. For habitat or dietary specialists, and subordinate predators that are vulnerable to both top-down and bottom-up ecosystem effects, these alterations may be detrimental and eventually incur population fitness costs. As the threat of bush encroachment continues, future studies are required to assess indirect effects on competitive interactions within the large African carnivore guild to ensure that conservation efforts are focused. Additionally, to better understand the effects of bush encroachment across Africa, further research is necessary in affected areas as overall little attention has been devoted to the topic.

Time to independence and predator–prey relationships of wild‐born, captive‐raised cheetahs released into private reserves in Namibia

“…Cheetahs appeared to use habitat for hunting in relatively equal proportions across vegetation classes. Although bush encroachment affects cheetah habitats in many regions (Atkinson et al., 2022a), cheetahs have been shown to hunt successfully in areas affected by woody cover up to a certain threshold (Atkinson et al., 2022b). While prey catchability for a specialised cursorial predator such as the cheetah might be most efficient in open areas, vegetation cover can provide safe refuge from scavengers especially in systems where dominant carnivores that represent a potential threat to cheetahs, such as lion and spotted hyaena are absent (Atkinson et al., 2022a).…”

“…Cheetahs appeared to use habitat for hunting in relatively equal proportions across vegetation classes. Although bush encroachment affects cheetah habitats in many regions (Atkinson et al, 2022a), cheetahs have been shown to hunt successfully in areas affected by woody cover up to a certain threshold (Atkinson et al, 2022b).…”

“…While prey catchability for a specialised cursorial predator such as the cheetah might be most efficient in open areas, vegetation cover can provide safe refuge from scavengers especially in systems where dominant carnivores that represent a potential threat to cheetahs, such as lion and spotted hyaena are absent (Atkinson et al, 2022a).…”

Rewilding landscapes with apex predators: cheetah (Acinonyx jubatus) movements reveal the importance of environmental and individual contexts

“…The movements of Rehabilitated Translocated cheetahs in relation to the hard edge between human-managed open savanna and bush encroached woodland savanna revealed a non-linear relationship. Habitat edges are often favoured by prey and also provide concealment, which can assist in hunting (Bissett and Bernard, 2007;Atkinson et al, 2022b).…”

“…The world's primary cheetah population stronghold is in southern Africa (Durant et al, 2017;Marker et al, 2018a), but cheetahs therein are subject to lethal persecution on livestock farms and in many areas must contend with bush encroachment, which can alter both predator and prey behaviours (Marker and Dickman, 2004;Nghikembua et al, 2021;Atkinson et al, 2022a;Nghikembua et al, 2023). Habitat change to woody vegetation potentially affects the cheetah's hunting strategies and energy acquisition, given their preference for open landscapes (Caro, 1994;Atkinson et al, 2022b). While both human-wildlife conflict and habitat change can be tackled with management and education, in some areas the cheetah populations are low or extinct, and restoration requires translocations for population recovery.…”