Long-Term Demography of Spotted Hyena () in a Lion-Depleted but Prey-Rich Ecosystem.

Interspecific competition has strongly shaped the evolution of large carnivore guilds. In Africa, the lion () and spotted hyena () exert direct and indirect competitive impacts on each other and on subordinate guild members. The impacts of competition on demography are complex and not well understood. With carnivore guilds now ubiquitously impacted by humans, disentangling the effects of interspecific competition and other drivers of hyena demography is important. Western Zambia's Greater Liuwa Ecosystem (GLE) provides a unique natural experiment where lions were functionally eliminated from the system. Hyenas are the apex predator, with an abundant prey base and low levels of human-hyena conflict. We measured GLE hyena survival and density using mark-recapture models fit to 10 years of data from 663 known individuals in 11 clans. GLE hyena densities were high, though slightly lower than other wildebeest-dominated systems, and stable over 10 years. Survival rates were high for all age-sex classes, and higher than those of other systems with high lion density, suggesting the possibility of competitive release from lion competition. These findings provide insights into long-term hyena demography in the absence of their top competitor but with an abundant prey base. As humans continue to alter ecosystems and fundamental ecological relationships such as interspecific competition, altered dynamics such as competitive release are likely to be widespread and should be a focus of future research.