Correlates of mid-winter pregnancy and early reproductive outcomes in a reintroduced elk (Cervus canadensis) population

Abstract

Determining the factors influencing reproductive rates is important for modeling and managing wildlife populations. In ungulates, these vital rates are often related to intrinsic characteristics such as age and body condition. We studied mid-winter pregnancy and early reproductive outcomes (offspring viability) in a reintroduced elk (Cervus canadensis) population in southeastern Kentucky, USA, modeling these rates as a function of age, body condition score, and body mass with generalized linear mixed-effects models (GLMMs) fit within an information-theoretic framework to determine which factors best predicted reproductive potential. Our models for pregnancy status suggested that pregnancy was strongly correlated with body mass and weakly with age and body condition, while models for offspring viability suggested that none of the covariates measured were predictive of parturition and offspring viability. While body mass appeared to be the strongest correlate of reproductive potential in this population, other physiological and nutritional variables likely play a role in pregnancy or fetal survival, and future work should aim to understand how these parameters both influence reproduction and are influenced by habitat management.