The Impact of the Invasive American Bullfrog (Lithobates catesbeianus) on Woodhouse Toad (Anaxyrus woodhousii) Demographics in the Rio Mora Wildlife Refuge in Northeastern NM

Poster: The introduction of Bullfrogs (Lithobates catesbeianus) has a negative impact on native species by out competing them for food and habitat. Woodhouse toads (Anaxyrus woodhousii) are among the native species to the Rio Mora National Wildlife Refuge (RMNWR) that co-exists with Bullfrogs. Early on bullfrogs were eradicated from a 2,600 meter section of the Mora River to evaluate the impact of their eradication on the local fauna while a control site of the river was left untouched where bullfrog density did not change. A parallel study on the diet of the euthanized bullfrogs found the presence of Woodhouse toads in their diet. The goal of this project is to investigate the impact of bullfrogs on Woodhouse toads by using three methods to determine differences between the control and experimental sites: (1) Determine abundance via two methods: A) a mark-recapture study demographic parameters (rate of increase, survival, capture rate). Distance sampling using random or systematic transects in the study area; (2) comparison of demographic structure using the animals caught in both sites; and (3) radio telemetry to explore habitat use and mobility of the Woodhouse toad as well as how it is affected by the presence of Bullfrogs.