USGS defends study that suggests U.S. climate may become accommodating to giant alien snakes

By Dr. Susan Haseltine
Associate Director for Biology, U.S. Geological Survey

This letter is written in response to your blog post of 07 December 2009 [Justification for Congressional python ban unscientific, researchers say] , regarding a press release issued by a reptile-trade organization and an accompanying letter by a group of veterinarians and other scientists.

The article and letter criticized the following recently released report (Reed and Rodda, 2009) U.S. Geological Survey written by  (USGS) scientists: Giant Constrictors: Biological and Management Profiles and an Establishment Risk Assessment for Nine Large Species of Pythons, Anacondas, and the Boa Constrictor.

Some of the information in the letter from Dr. Jacobson and fellow scientists appears to be based on a misunderstanding of the USGS peer review process.
The USGS provides unbiased, objective scientific information upon which other entities may base judgments. To ensure objectivity, independent scientific review is required of every USGS publication. Standards require a minimum of two reviews, and adequacy of the author’s responses to reviews is assessed by both research managers and independent scientists within the USGS.
For the report referred to in the blog, the authors went well beyond the requirements by soliciting reviews from 20 reviewers (18 of them external to the USGS). Reviewers comprised a large portion of the global expertise on both the biology of giant constrictor snakes and the management of invasive snakes.
In addition, the climate-matching methods presented in the report were previously published in the peer-reviewed journal Biological Invasions in early 2009 (Rodda et al., 2009), so these methods have received both USGS peer review and standard journal peer review.
Scientific papers with divergent or competing views on issues are very common and contribute to advancing scientific processes. The Biological Invasions paper had been criticized in a subsequent publication (Pyron et al., 2008).
In the current USGS report, the authors addressed the limitations of the methods utilized in the Pyron et al. (2008) paper.
The USGS report reviewed virtually all of the peer-reviewed literature on giant constrictor biology, as well as much of the literature on snake management (a total of 671 papers and books) and survival in the wild. The report has received favorable review by other invasion biologists including one written by one of the world’s most respected experts in invasive species biology (Dan Simberloff, Ph.D., Univ. Tennessee). The review (Simberloff, 2009) recently appeared in the journal Biological Invasions and can be found here.
With regard to climate-matching in particular, Simberloff praised the “excellent discussion of the differences between and relative merits of climate matching approaches and environmental niche models that would constitute a good introduction to this burgeoning literature for any graduate student and most practicing invasion biologists.
“While allegations have been made that the USGS report is being used as the justification for regulations on the reptile trade, it is important to note that the report offers no recommendations on policy or legislation.
Thank you for the opportunity to offer clarification on these issues.

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