Abstract
Three separate breeding populations of the Nile monitor (Varanus niloticus) have been identified in Florida, USA, located in Cape Coral, West Palm Beach and Homestead Air Reserve Base. This large, predatory lizard could have negative effects on Florida's native wildlife. Here, we infer the source of the introduced populations using genetic and statistical approaches, as well as estimate the potential non-native distribution of V. niloticus in North America. We collected genetic data from 25 Florida individuals as well as utilized genetic datasets from reference individuals spanning the full native distribution throughout sub-Saharan Africa. Using occurrence data from the inferred source population and the full species range, we built ecological niche models (ENMs) and projected them onto North America to determine regions with suitable climate. Our results indicated that the introduced populations resulted from three separate introduction events, and all originated from the southern coastal region of West Africa. The ENM built from the West African source population predicted only the southernmost portions of North America to be suitable. Conversely, the model derived from the full species’ range predicted suitable climates across a large portion of the United States. This information can be used to focus management and eradication efforts.
Highlights
The prevalence of introduced species continues to rise as a consequence of globalization and expanding human transportation [1,2]
We identify the geographical origin of the introduced V. niloticus populations using both genealogical methods and frequency-based approaches
Our results suggest that the introduced V. niloticus populations inhabiting Cape Coral, West Palm Beach and Homestead resulted from three separate introduction events
Summary
The prevalence of introduced species continues to rise as a consequence of globalization and expanding human transportation [1,2]. While a majority of non-native organisms fail to survive and become established [3], those that do can cause severe harm to native ecosystems [4,5]. Negative effects of introduced species on native populations often include competition for resources [8], predation of native species [9], habitat alteration [10], and the introduction of novel parasites and diseases [11]. USA, has been disproportionately affected by introduced organisms, supporting the highest number of established non-native herpetofauna in the world [12]. The cumulative effects of introduced alien species have placed an enormous burden on the fragile Florida ecosystem [13]
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