AMRE-1361_Supplementary material.pdf (250.8 kB)
Download fileSurvival estimates for the invasive American bullfrog
journal contribution
posted on 2020-06-02, 08:14 authored by Paige E. Howell, Erin Muths, Brent H. Sigafus, Blake R. HossackAmerican bullfrogs (Lithobates catesbeianus) are significant invaders in many places
and can negatively impact native species. Despite their impact and wide
distribution, little is known about their demography. We used five years of capture
mark-recapture data to estimate annual apparent survival of post-metamorphic
bullfrogs in a population on the Buenos Aires National Wildlife Refuge in their
invaded range in Arizona, U.S.A. This population is a potential source of colonists
into breeding ponds used by the federally threatened Chiricahua leopard frog (L. chiricahuensis).
Results from robust-design Cormack-Jolly-Seber models suggested that survival of
bullfrogs was influenced by sex and precipitation but not body condition. Survival
was higher for females (mean = 0.37; 95% CI
= 0.15, 0.72) than males (mean = 0.17; 95% CI
= 0.02, 0.49), and declined with reduced annual precipitation (mean = ‒0.36,
95% CI = ‒2.09, 0.84). These survival
estimates can be incorporated into models of population dynamics and to help predict
spread of bullfrogs.