Winter temperatures may exert some influence over northern range limits of Burmese pythons. The native range of Burmese pythons extends from tropical zones in Southeast Asia (including Vietnam, Cambodia, Laos, and Thailand) to warm temperate zones in China and Nepal (Groombridge and Luxmoore 1991 Zhao and Adler 1993 Whitaker and Captain 2004). As an example of the latter, several attempts have been made to use native-range climatic variables to predict potential distribution of Burmese pythons in the United States, but results have been inconsistent and even contradictory (Pyron et al. 2009), and methodological or statistical uncertainties (Randin et al. 2005 Kraus 2009).Īlthough climate is often proposed as a primary factor limiting potential geographic extent of invading species, predicting potential range of an invasive species is difficult because of a poor understanding of predictors of invasive ranges (Hayes and Barry 2008), observations that native range climate may under-predict invasive range distribution (Fitzpatrick et al. Ecological and economic impacts of invasive animals such as pythons depend on types and magnitude of impacts (e.g., predation on or competition with native species) and geographic extent of invasion (Pimentel et al. Considerable concern has been expressed over their impacts on south Florida ecosystems, particularly in ENP, where Burmese pythons consume primarily birds and mammals (Snow et al. 2007a).īurmese pythons are habitat and dietary generalists (Reed and Rodda 2009). The Burmese python is native to Southeast Asia and is established in natural areas in southern Florida such as Everglades National Park (ENP) (Snow et al. Many of the more than 40 exotic reptile species established in Florida are confined to urban or otherwise manmade habitats such as backyards and canals however, several species (e.g., Burmese python, Python molurus bivittatus) have successfully invaded natural habitats. The United States dominates the world trade in live reptiles (Hoover 1998 Franke and Telecky 2001), and the state of Florida alone currently hosts more established alien reptiles than any other state or nation (Meshaka et al. Invasive alien reptiles present an increasing challenge to conservation of biological diversity (Wilcove et al. We discuss implications of our findings for persistence and spread of introduced Burmese pythons in the United States and for maximizing their rate of removal. Some radio-telemetered pythons appeared to exhibit maladaptive behavior during the cold spell, including attempting to bask instead of retreating to sheltered refugia. Unusually cold temperatures in January 2010 were clearly associated with mortality of Burmese pythons in the Everglades. Body temperatures of eight dead telemetered pythons fluctuated regularly prior to 9 January 2010, then declined substantially during the cold period (9–11 January) and exhibited no further evidence of active thermoregulation indicating they were likely dead. Only one of 10 telemetered pythons survived the cold snap, whereas 59 of 99 (60%) non-telemetered pythons for which we determined fate survived. Telemetered pythons had been implanted with radio-transmitters and temperature-recording data loggers prior to the cold snap. We observed behavior, characterized thermal biology, determined fate of radio-telemetered ( n = 10) and non-telemetered ( n = 104) Burmese pythons, and analyzed habitat and environmental conditions experienced by pythons during and after a historic cold spell. A recent record cold spell in southern Florida (2–11 January 2010) provided an opportunity to evaluate responses of an established population of Burmese pythons ( Python molurus bivittatus) to a prolonged period of unusually cold weather.
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