A field test of attractant traps for invasive Burmese pythons (Python molurus bivittatus) in southern Florida
Robert N. Reed A E , Kristen M. Hart B , Gordon H. Rodda A , Frank J. Mazzotti C , Ray W. Snow D , Michael Cherkiss C , Ronald Rozar A and Scott Goetz AA US Geological Survey, Fort Collins Science Center, 2150 Centre Ave, Bldg C, Fort Collins, CO 80526, USA.
B US Geological Survey, Southeast Ecological Science Center, Davie Field Office, 3205 College Ave, Davie, FL 33314, USA.
C Fort Lauderdale Research and Education Center, University of Florida, 3205 College Ave, Davie, FL 33314, USA.
D National Park Service, Everglades National Park, 40001 State Road 9336, Homestead, FL 33034, USA.
E Corresponding author. Email: reedr@usgs.gov
Wildlife Research 38(2) 114-121 https://doi.org/10.1071/WR10202
Submitted: 4 November 2010 Accepted: 1 February 2011 Published: 20 April 2011
Abstract
Context: Invasive Burmese pythons (Python molurus bivittatus) are established over thousands of square kilometres of southern Florida, USA, and consume a wide range of native vertebrates. Few tools are available to control the python population, and none of the available tools have been validated in the field to assess capture success as a proportion of pythons available to be captured.
Aims: Our primary aim was to conduct a trap trial for capturing invasive pythons in an area east of Everglades National Park, where many pythons had been captured in previous years, to assess the efficacy of traps for population control. We also aimed to compare results of visual surveys with trap capture rates, to determine capture rates of non-target species, and to assess capture rates as a proportion of resident pythons in the study area.
Methods: We conducted a medium-scale (6053 trap nights) experiment using two types of attractant traps baited with live rats in the Frog Pond area east of Everglades National Park. We also conducted standardised and opportunistic visual surveys in the trapping area. Following the trap trial, the area was disc harrowed to expose pythons and allow calculation of an index of the number of resident pythons.
Key results: We captured three pythons and 69 individuals of various rodent, amphibian, and reptile species in traps. Eleven pythons were discovered during disc harrowing operations, as were large numbers of rodents.
Conclusions: The trap trial captured a relatively small proportion of the pythons that appeared to be present in the study area, although previous research suggests that trap capture rates improve with additional testing of alternative trap designs. Potential negative impacts to non-target species were minimal. Low python capture rates may have been associated with extremely high local prey abundances during the trap experiment.
Implications: Results of this trial illustrate many of the challenges in implementing and interpreting results from tests of control tools for large cryptic predators such as Burmese pythons.
References
Alexander, G. J., and Marais, J. (2007). ‘A Guide to the Reptiles of Southern Africa.’ (Struik: Cape Town, South Africa.)Auliya, M. A. (2006). ‘Taxonomy, Life History and Conservation of Giant Reptiles in West Kalimantan (Indonesian Borneo).’ (Natur und Tier Verlag: Munich.)
Branch, W. R. (1988). ‘South Africa Red Data Book – Reptiles and Amphibians.’ (Foundation for Research Development: Pretoria, South Africa.)
Christy, M. T., Yackel Adams, A. A., Rodda, G. H., Savidge, J. A., and Tyrrell, C. L. (2010). Modelling detection probabilities to evaluate management and control tools for an invasive species. Journal of Applied Ecology 47, 106–113.
| Modelling detection probabilities to evaluate management and control tools for an invasive species.Crossref | GoogleScholarGoogle Scholar |
Dargan, L. M., and Stickel, W. H. (1949). An experiment with snake trapping. Copeia 1949, 264–268.
| An experiment with snake trapping.Crossref | GoogleScholarGoogle Scholar |
Dirksen, L. (2002). ‘Anakondas: Monographische Revision der Gattung Eunectes Wagler, 1830 (Serpentes, Boidae).’ (Natur und Tier Verlag: Münster.)
Dorcas, M. E., and Willson, J. D. (2009). Innovative methods for studies of snake ecology and conservation. In ‘Snakes: Ecology and Conservation’. (Eds S. J. Mullin and R. A. Seigel.) pp. 5–37. (Cornell University Press: Ithaca, NY.)
Fitch, H. S. (1951). A simplified type of funnel trap for reptiles. Herpetologica 7, 77–80.
Fitch, H. S. (1987). Collecting and life-history techniques. In ‘Snakes: Ecology and Evolutionary Biology’. (Eds R. A. Seigel, J. T. Collins and S. S. Novak.) pp. 143–164. (Macmillan: New York, NY.)
Gibbons, J. W., and Semlitsch, R. D. (1981). Terrestrial drift fences with pitfall traps: an effective technique for quantitative sampling of animal populations. Brimleyana 7, 1–16.
Gragg, J. E., Rodda, G. H., Savidge, J. A., White, G. C., Dean-Bradley, K., and Ellingson, A. R. (2007). Response of brown tree snakes to reduction of their rodent prey. The Journal of Wildlife Management 71, 2311–2317.
| Response of brown tree snakes to reduction of their rodent prey.Crossref | GoogleScholarGoogle Scholar |
Greene, D. U., Potts, J. M., Duquesnel, J. G., and Snow, R. W. (2007). Python molurus bivittatus (Burmese python). Herpetological Review 38, 355.
Harvey, R. G., Brien, M. L., Cherkiss, M. S., Dorcas, M. E., Rochford, M. R., Snow, R. W., and Mazzotti, F. J. (2008). Burmese pythons in south Florida: scientific support for invasive species management. (University of Florida: Fort Lauderdale, FL.) Available at: http://edis.ifas.ufl.edu/UW286 [verified March 2011].
Hayashi, Y., Kihara, H., Tanaka, H., and Kurosawa, M. (1985). Evaluation of a bait trap for Habu, the venomous snake, Trimeresurus flavoviridis. Snake 17, 87.
Jackley, A. M. (1943). New snake trap and some of its strange catches. South Dakota Conservation Digest 10, 1–7.
Keck, M. B. (1994). A new technique for sampling semi-aquatic snake populations. Herpetological Natural History 1994, 101–103.
Kihara, H., Hayashi, Y., and Wakisaka, I. (1978). Studies on attractants to Habu using traps. Snake 10, 46–55.
Kraus, F. (2009). ‘Alien Reptiles and Amphibians: a Scientific Compendium and Analysis.’ (Springer Series in Invasion Biology: New York, NY.)
Maritz, B., Masteron, G., Mackay, D., and Alexander, G. (2007). The effect of funnel trap type and size of pitfall trap on trap success: implications for ecological field studies. Amphibia-Reptilia 28, 321–328.
| The effect of funnel trap type and size of pitfall trap on trap success: implications for ecological field studies.Crossref | GoogleScholarGoogle Scholar |
Martins, M., and Oliveira, M. E. (1998). Natural history of snakes in forests of the Manaus region, Central Amazonia, Brazil. Herpetological Natural History 6, 78–150.
National Park Service (2010). Burmese python: species profile. Available at: http://www.nps.gov/ever/naturescience/burmesepython.htm [verified 15 Sept. 2010].
Pimentel, D. (2007). Environmental and economic costs of vertebrate species invasions into the United States. In ‘Managing Vertebrate Invasive Species: Proceedings of an International Symposium’. (Eds G. W. Witmer, W. C. Pitt and K. A. Fagerstone.) pp. 2–8. (USDA-APHIS Wildlife Services National Wildlife Research Center: Fort Collins, CO.)
Pimentel, D., Zuniga, R., and Morrison, D. (2005). Update on the environmental and economic costs associated with alien-invasive species in the United States. Ecological Economics 52, 273–288.
Reed, R. N., and Rodda, G. H. (2009). Giant constrictors: biological and management profiles and an establishment risk assessment for nine large species of pythons, anacondas, and the boa constrictor. US Geological Survey open file report 2009–1202. (US Geological Survey: Washington D.C., WA.)
Reed, R. N., Boback, S. M., Montgomery, C. E., Green, S., Stevens, Z., and Watson, D. (2007). Ecology and conservation of an exploited insular population of Boa constrictor (Squamata : Boidae) in the Cayos Cochinos, Honduras. In ‘Biology of the Boas and Pythons’. (Eds R. W. Henderson and R. Powell.) pp. 389–403. (Eagle Mountain Publishing: Eagle Mountain, UT.)
Reed, R. N., Krysko, K. L., Snow, R. W., and Rodda, G. H. (2010). Is the Northern African Python (Python sebae) established in southern Florida? IRCF Reptiles and Amphibians 17, 52–54.
Rodda, G. H., Sawai, Y., Chiszar, D., and Tanaka, H. (1999a). ‘Problem Snake Management: the Habu and the Brown Treesnake.’ (Cornell University Press: Ithaca, NY.)
Rodda, G. H., Fritts, T. H., Clark, C. S., Gotte, S. W., and Chiszar, D. (1999b). A state-of-the-art trap for the brown treesnake. In ‘Problem Snake Management: the Habu and the Brown Treesnake’. (Eds G. H. Rodda, S. Yoshio, D. Chiszar and H. Tanaka.) pp. 268–305. (Cornell University Press: Ithaca, NY.)
Rodda, G. H., Savidge, J. A., Tyrrell, C. L., Christy, M. T., and Ellingson, A. R. (2007). Size bias in visual searching and trapping of brown treesnakes on Guam. The Journal of Wildlife Management 71, 656–661.
| Size bias in visual searching and trapping of brown treesnakes on Guam.Crossref | GoogleScholarGoogle Scholar |
Shiroma, H., and Akamine, H. (1999). Complete removal of Habu, Trimeresurus flavoviridis, from a residential area by trapping. In ‘Problem Snake Management: the Habu and the Brown Treesnake’. (Eds G. H. Rodda, S. Yoshio, D. Chiszar and H. Tanaka.) pp. 327–339. (Cornell University Press: Ithaca, NY.)
Simmons, J. E. (2002). ‘Herpetological Collecting and Collections Management.’ 2nd edn. (Society for the Study of Amphibians and Reptiles, Herpetological Circular No. 31: Salt Lake City, UT.)
Snow, R. W., Krysko, K. L., Enge, K. M., Oberhofer, L., Warren-Bradley, A., and Wilkins, L. (2007a). Introduced populations of Boa constrictor (Boidae) and Python molurus bivittatus (Pythonidae) in southern Florida. In ‘Biology of the Boas and Pythons’. (Eds R. W. Henderson and R. Powell.) pp. 416–438. (Eagle Mountain Publishing: Eagle Mountain, UT.)
Snow, R. W., Brien, M. L., Cherkiss, M. S., Wilkins, L., and Mazzotti, F. J. (2007b). Dietary habits of Burmese python, Python molurus bivittatus, from Everglades National Park, Florida. Herpetological Bulletin 101, 5–7.
Tyrrell, C. L., Christy, M. T., Rodda, G. H., Yackel Adams, A. A., Ellingson, A. R., Savidge, J. A., Dean-Bradley, K., and Bischof, R. (2009). Evaluation of trap capture in a geographically closed population of Brown Treesnakes on Guam. Journal of Applied Ecology 46, 128–135.
| Evaluation of trap capture in a geographically closed population of Brown Treesnakes on Guam.Crossref | GoogleScholarGoogle Scholar |
Veitch, C. R., and Clout, M. N. (2002). ‘Turning the Tide: the Eradication of Invasive Species.’ (IUCN Invasive Species Specialist Group of the World Conservation Union: Gland, Switzerland.)
Willson, J. D., Winne, C. T., and Keck, M. B. (2008). Empirical tests of biased body size distributions in aquatic snake captures. Copeia 2008, 401–408.
| Empirical tests of biased body size distributions in aquatic snake captures.Crossref | GoogleScholarGoogle Scholar |
Witmer, G. W., Pitt, W. C., and Fagerstone, K. A. (Eds) (2007). ‘Managing Vertebrate Invasive Species: Proceedings of an International Symposium.’ (USDA-APHIS Wildlife Services National Wildlife Research Center: Fort Collins, CO.)
