Sunday, October 7, 2012

Why is Python bivittatus so successful in Florida?

Python bivittatus. JCM

Why has the Burmese python (Python bivittatus) been so successful at invading southern Florida while other species have been less successful  The invasive pythons have caused precipitous population declines among several species of native mammals.  Reed et al (2012) examine the reasons for the snake's success  by scoring the Burmese python for each of 15 literature-based attributes from a diverse range of taxa and provide a review of the natural history and ecology of Burmese pythons relevant to each attribute. The authors  focus on attributes linked to spread and magnitude of impacts rather than establishment success. Their results suggest that attributes related to body size and its generalist habits appear to be particularly applicable to the Burmese python's success in Florida. The attributes with the highest scores were: high reproductive potential, low vulnerability to predation, large adult body size, large offspring size and high dietary breadth. However, attributes of ectotherms in general and pythons in particular (including predatory mode, energetic efficiency and social interactions) might have also contributed to invasion success.

The  ranking exercise suggested that Burmese pythons might be somewhat atypical of boas and pythons in terms of their likelihood to spread as invasive species and impact native ecosystems. Burmese pythons ranked equal to, or higher than, a ‘typical’ boa or python species for every invasion-related trait we considered, and scored particularly high in traits related to size and degree of parental care. These traits, combined with their popularity in the pet trade and a large global climate match compared to the other giant constrictors likely make Burmese pythons a higher risk for introductions elsewhere.

Although establishment risk assessments are an important initial step in prevention of new establishments, evaluating species in terms of their potential for spreading widely and negatively impacting ecosystems might become part of the means by which resource managers prioritize control efforts in environments with large numbers of introduced species.

The article is available on-line.

REED, R. N., WILLSON, J. D., RODDA, G. H. and DORCAS, M. E. (2012), Ecological correlates of invasion impact for Burmese pythons in Florida. Integrative Zoology, 7: 254–270. doi: 10.1111/j.1749-4877.2012.00304.x

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