Exotic Hobos: Release, escape, and potential secondary dispersal of African red-headed agamas (Agama picticauda PETERS, 1877) through the Florida railway systems

Abstract

ABSTRACTContextInvasive reptile species are introduced and established through a variety of distribution channels (e.g. accidental/intentional release by pet owners, hitchhiking on imported goods), and can be detrimental to native ecosystems. Understanding the origins and spread of non-native species can help land managers to make informed decisions when attempting to prevent future introductions and remove established populations.AimsThe objectives of this study were to employ modelling techniques with open-source observational data to confirm putative local origins of African red-headed agamas in Florida and to locate potential distribution channels in which they are spreading throughout the state.MethodsGeographic profiling, a technique commonly used for criminal investigations, was used along with suspected origin locations of introduced African red-headed agamas (Agama picticauda) from the literature and observations from the Early Detection and Distribution Mapping System (EDDMapS). Anchor points and their immediate surroundings were investigated for potential patterns of origination and dispersal.Key resultsThe results of this study provide evidence that African red-headed agamas likely established themselves through both intentional releases and unintentional escapes from the pet owners and breeders, while also potentially hitchhiking on plant exports, and dispersing throughout Florida via the railway systems.ConclusionsGiven the potential for railways as a method of assisted dispersal, and given the potential exports they may be hitchhiking on, the results of this study suggest that railcars and railway export facilities should be included in future management of non-native African red-headed agamas in Florida.ImplicationsThe implications of this study builds on prior evidence that geographic profiling is an effective modelling tool in regards to biological invasions, which can accurately confirm suspected origins while also effectively mapping previously unknown epicenters of population clusters to be investigated by managers.