Review of range-wide vital rates quantifies Eastern Wild Turkey
population trajectory
Abstract
Recent declines in eastern wild turkeys (Meleagris gallopavo silvestris)
has prompted increased interest in management and research of this
important game species. However, the mechanisms underlying these
declines are unclear, leaving uncertainty in how best to manage this
species. Foundational to effective management of wildlife species is
understanding the biotic and abiotic factors that influence demographic
parameters and the contribution of vital rates to population growth. Our
objectives for this study were to: 1) conduct a literature review to
collect all published vital rates for eastern wild turkey over the last
50 years, 2) perform a scoping review of the biotic and abiotic factors
that have been studied relative to wild turkey vital rates and highlight
areas that require additional research, and 3) use the published vital
rates to populate a life-stage simulation analysis (LSA) and identify
the vital rates that make the greatest contribution to population
growth. Based on published vital rates for eastern wild turkey, we
estimated a mean asymptotic population growth rate (λ) of 0.91 (95% CI
= 0.71, 1.12). Vital rates associated with after second year (ASY)
females were most influential in determining population growth. Survival
of ASY females had the greatest elasticity (0.53), while reproduction of
ASY females had lower elasticity (0.21), but high process variance,
causing it to explain a greater proportion of variance in λ. Our scoping
review found that most research has focused on the effects of habitat
characteristics at nest sites and the direct effects of harvest on adult
survival, while research on topics such as disease, weather, predators,
or anthropogenic activity on vital rates have received less attention.
We recommend that future research take a more mechanistic approach to
understanding variation in wild turkey vital rates as this will assist
managers in determining the most appropriate management approach.