From Laboratories to Landscapes: Quantifying the Effects of Human Poaching on Predator-Prey Interactions

Empirical research on the community ecology of predators and prey has revealed that predators can impact prey populations directly and indirectly1,2. Direct effects, also known as consumptive effects, refer to the direct consumption of prey individuals, which may influence prey population dynamics and size. Indirect effects, also known as non-consumptive or risk effects, refer to the cost of antipredator behaviors in response to predation risk1,3. From a behavioral lens, anti-predator responses may include changes in habitat use, foraging rates, movement patterns, and/or temporal activity4,5. These risk-induced changes in prey behavior can have cascading impacts, resulting in indirect effects on lower trophic levels and competitive interactions with other species6,7. Studies measuring the impacts of risk effects have predominately been measured via study of small organisms in controlled experiments within laboratories or mesocosms8. These experimental designs afford the ability to replicate treatments, control environmental variables, and ultimately isolate the mechanisms driving species interactions. However, whether the insights gained from these studies may be generalizable to the landscape scale, containing large and highly mobile species, remains unresolved and requires further testing 8,9. Furthermore, it is unclear whether the effects of humans, as a "super predator" species, can alter community dynamics through top-down pressures10,11. This is in part because the mechanisms by which human induced risk effects shape spatial food web dynamics has not been widely studied. The nature and strength of human-wildlife interactions are often landscape contingent, requiring new theoretical and empirical approaches for establishing generalizable predictability8,12.
Via the process of scaling risk effects research from the laboratory to the landscape level, my doctoral research aims to experimentally quantify the indirect effects of human predation, via subsistence poaching, on multi-species interactions. This project will be carried out through the novel application of the habitat domain theory in Murchison Falls National Park, Uganda (MFNP). In collaboration with Dr. Robert Montgomery and the Ugandan Wildlife Authority, this research will investigate how human-predation risk alters spatiotemporal patterns in predator-prey interactions.