Hierarchical Bayesian Integrated Modeling of Age- and Sex-Structured Wildlife Population Dynamics

Area of Science:

• Wildlife ecology
• Conservation biology
• Population dynamics

Background:

• Global decline of large wild mammal biodiversity necessitates effective conservation strategies.
• Existing population dynamics models are insufficient for wild herbivores, hindering conservation efforts.
• A novel modeling approach is required to characterize herbivore population declines and inform management.

Purpose of the Study:

• To develop an integrated Bayesian state-space population dynamics model for wildlife populations.
• To apply the model to the topi population in the Greater Mara-Serengeti Ecosystem.
• To provide a tool for characterizing declines and guiding conservation actions for wild herbivores.

Main Methods:

• Developed an integrated Bayesian state-space population dynamics model.
• Integrated ground demographic and aerial survey data.
• Incorporated age/sex structure, life history traits, and environmental covariates (meteorology, density, seasonality, predation).
• Utilized monthly time steps for detailed reproductive and recruitment analysis.
• Employed Markov Chain Monte Carlo (MCMC) methods for parameter estimation and inference.

Main Results:

• The model accurately characterized the Mara topi population's decline and seasonality of births and recruitment.
• Model performance was validated using bootstrap sampling and comparison with empirical data.
• The model successfully reproduced known features of the Mara topi population dynamics.
• Identified key factors influencing birth rates, survival rates, and sex ratios.

Conclusions:

• The developed Bayesian model is a valuable tool for understanding and managing wild herbivore populations.
• The model's generality allows adaptation for other wildlife species and future extensions.
• This approach can significantly enhance population conservation and recovery strategies for declining species.
• Provides crucial insights into the drivers of population dynamics in ecologically important herbivores.