Invasive Cuban Treefrog and its Potential Dis-tribution with Climate Change

The Cuban treefrog (Osteopilus septentrionalis) is an invasive species which, in the last couple of decades, has begun to spread to many different areas of the Americas. The natural distribution of the frog includes Cuba and the Bahamas, Isla de la Juventud, San Salvador, the Acklins Islands, and the Cayman Islands. Recently, the Cuban treefrog’s habitat has expanded to include Anguilla, the British Virgin Islands, Florida, the French Antilleans, Puerto Rico, and the Virgin Islands. The frog was probably introduced in the 1930s, by accident, as an undetected stowaway in imported vegetables from Cuba. Right now breeding populations can be found as far north as Jacksonville and individuals have been reported in places as far as coastal Georgia and South Carolina. The high invasiveness of the Cuban treefrog can be attributed to its high fecundity, short larval period, broad diet, and broad habitat and dietary niches. The frog may have major impacts on native species because it is the biggest hylid in the US and could easily outcompete other species. Also, the tadpoles are omnivorous, cannibalistic, and could potentially eat the eggs of indigenous frogs. One feature limiting the distribution of the Cuban treefrog is climatic suitability, however, with the onset of anthropogenic climate change, range-size patterns for the treefrog are expected to increase even further. Geographic information systems-based climate envelope models (CEMs) are used to assess the potential distribution of species derived from their climate niches. The models were used to predict potential distribution of the frog under current climate conditions and as well as potential distribution due to anthropogenic global warming. Models suggest that global warming is very likely to increase the range of the Cuban treefrog. — Patricio Ku
Rodder, D., Weinsheimer, F., 2009. Will future anthropogenic climate change increase the potential distribution of the alien invasive Cuban treefrog (Anura: Hylidae). Journal of Natural History 43, 1207–1217

Rődder and Weinsheimer used 6665 records of the Cuban treefrog that were available thought the Global Biodiversity Information Facility (GBIF) for their model. The climate information was taken from the WorldClim database where the cumulative frequency of biolimatic parameters was plotted with DIVA-GIS. The CEM used was Maxent 3.2.1 where the model assessed the potential distribution of the Cuban treefrog. The Maxent model allows for model testing by calculation of the Area Under the Curve (AUC) which uses either the invasive records as test points and the native records for training, or all native records for training and background points for testing.
The CEM suggests that the Cuban treefrog can find suitable regions all over the Caribbean and the countries adjacent to the Gulf of Mexico. Projections onto anthropogenic climate-change scenarios indicate an extension of the current distribution of the Cuban treefrog in Northern America. In addition to natural propagation, human-facilitated propagation is an important factor to consider when mapping the distribution of the frog. The national and international plant trade can displace species in remote places and encourage their spread. Means of control must focus on prevention rather than trying to avoid further spreading through human activities. Regional differences in population structure and fitness may also require different regulation or eradication approaches. As a result of increased climatic suitability, a more aggressive control strategy must be put in to place in order to help control the population of the Cuban treefrog.

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