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RESEARCH ARTICLE
Contents Vol 35(7)

Aerially applied citric acid reduces the density of an invasive frog in Hawaii, USA

Nathania C. Tuttle A , Karen H. Beard A C and Robert Al-Chokhachy B
+ Author Affiliations
- Author Affiliations

A Utah State University, Department of Wildland Resources and the Ecology Center, Logan, UT 84322-5230, USA.

B Utah State University, Department of Watershed Sciences, Logan, UT 84322-5210, USA.

C Corresponding author. Email: karen.beard@usu.edu

Wildlife Research 35(7) 676-683 https://doi.org/10.1071/WR07135
Submitted: 6 September 2007  Accepted: 21 July 2008   Published: 17 November 2008

Abstract

The Puerto Rican frog (Eleutherodactylus coqui) is an invasive pest in Hawaii. Citric acid is approved for controlling these frogs, but has been limited to terrain accessible by foot or vehicle. We determined the effectiveness of helicopter applications of 16% citric acid and repeated 11% citric acid treatments for eradicating and/or reducing densities of E. coqui by monitoring populations before and after treatment using mark–recapture. We also evaluated the effects of the marking technique, toe-clipping, and weather changes on population parameter estimates. We found that a 16% citric acid treatment appears to have reduced adult E. coqui density 3-fold in a plot, T1, completely covered with citric acid, but did not reduce adult density in a plot, T2, where 6% of the plot was unintentionally not treated. Preadults were reduced 3- to 5-fold in treated plots. The apparent reduction in adults in T1 lasted at least 5 months. Repeated treatments of 11% citric acid were studied in T2 and likely reduced adults 440-fold while preadults were reduced 9-fold. E. coqui that had fewer toe-clips had greater recapture probability and survival estimates, while weather had no effect on parameter estimates. In summary, we found that 16% and 11% citric acid treatments can reduce E. coqui density, treatment effects can last 5 months for adults, and repeated treatments appear more effective for reducing density than single applications.


Acknowledgements

Funding was provided by the Jack H. Berryman Institute and the Hawaii Department of Land and Natural Resources (Hawaii Invasive Species Council). L. Hadway and the State of Hawaii NARS applied the citric acid and provided housing. We thank M. Tuttle, A. Huff, and M. Higashi for field assistance, R. Ryel, and W. Pitt and the USDA/APHIS/WS/NWRC Hilo field station for vehicles, M. Conner and P. Budy for help with program MARK, and W. Pitt, M. Conner, P. Budy, and three anonymous referees for reviewing previous versions of this manuscript. Procedures were performed with the approval of Utah State University’s Institutional Animal Care and Use Committee permit number 1145R.


References

Beard K. H. (2001). The ecological roles of a terrestrial frog, Eleutherodactylus coqui (Thomas), in the nutrient cycles of a subtropical wet forest in Puerto Rico. Ph.D. Dissertation, Yale University, New Haven.

Beard, K. H. (2007). Diet of the invasive frog, Eleutherodactylus coqui, in Hawaii. Copeia 2007, 281–291.
| Crossref | GoogleScholarGoogle Scholar | Burnham K. P. , and Anderson D. R. (1998). ‘Model Selection and Inference: a Practical Information-Theoretic Approach.’ (Springer-Verlag: New York.)

Burrowes, P. A. , Joglar, R. L. , and Green, D. E. (2004). Potential causes for amphibian declines in Puerto Rico. Herpetologica 60, 141–154.
| Crossref | GoogleScholarGoogle Scholar | Campbell E. W. (2002). Dermal toxicity of selected agricultural pesticides, pharmaceutical products, and household chemicals to introduced Eleutherodactylus frogs in Hawaii. Report no. QA-693. USDA/APHIS/WS/NWRC, Hilo, Hawaii.

Clarke, R. D. (1972). The effect of toe clipping on survival in Fowler’s toad (Bufo woodhousei fowleri). Copeia 1972, 182–185.
| Crossref | GoogleScholarGoogle Scholar | Giambelluca T. W. , Nullet M. A. , and Schroeder P. A. (1986). ‘Rainfall Atlas of Hawaii.’ (Department of Land and Natural Resources: Honolulu.)

Hawaii Department of Land and Natural Resources/Hawaii Invasive Species Council (HDLNR/HISC) (2006). Hawaii’s coqui frog management, research, and education plan. Honolulu, Hawaii.

Kaiser, B. , and Burnett, K. (2006). Economic impacts of E. coqui frogs in Hawaii. Interdisciplinary Environmental Review 8, 1–11.
Kraus F. (2003). Invasion pathways of terrestrial vertebrates. In ‘Invasive Species: Vectors and Management Strategies’. (Eds G. M. Ruiz and J. T. Carlton.) pp. 68–92. (Island Press: Washington, DC.)

Kraus, F. , and Campbell, E. W. (2002). Human-mediated escalation of a formerly eradicable problem: the invasion of Caribbean frogs in the Hawaiian islands. Biological Invasions 4, 327–332.
| Crossref | GoogleScholarGoogle Scholar | Nullet D. , and Sanderson M. (1993). Radiation and energy balances and air temperatures. In ‘Prevailing Trade Winds: Weather and Climate in Hawaii’. (Ed. M. Sanderson.) pp. 37–55. (University of Hawaii Press: Honolulu.)

Ohashi T. (2004). Final environmental assessment: Caribbean tree frog control in the state of Hawaii. USDA/APHIS/WS, Volcano, Hawaii.

Ostertag, R. , and Verville, J. H. (2002). Fertilization with nitrogen and phosphorus increases abundance of non-native species in Hawaiian montane forests. Plant Ecology 162, 77–90.
| Crossref | GoogleScholarGoogle Scholar | Pitt W. C. , and Sin H. (2004 a). Dermal toxicity of citric acid based pesticides to introduced Eleutherodactylus frogs in Hawaii. Report no. QA-992. USDA/APHIS/WS/NWRC, Hilo, Hawaii.

Pitt W. C. , and Sin H. (2004 b). Field efficacy and invertebrate non-target hazard assessment of citric acid spray application for control of introduced Eleutherodactylus frogs in Hawaii. Report no. QA-1048. USDA/APHIS/WS/NWRC, Hilo, Hawaii.

Pitt, W. C. , and Sin, H. (2004c). Testing citric acid use on plants. Landscape Hawaii, July/August , 5.
Price S. (1983). Climate. In ‘Atlas of Hawaii’. (Ed. R. W. Armstrong.) pp. 59–66. (University of Hawaii Press: Honolulu.)

Reaser, J. K. , and Dexter, R. E. (1996). Rana pretiosa (spotted frog). Toe clipping effects. Herpetological Review 27, 195–196.
Stewart M. M. , and Woolbright L. L. (1996). Amphibians. In ‘The Food Web of a Tropical Rain Forest’. (Eds D. P. Reagan and R. B. Waide.) pp. 363–398. (University of Chicago Press: Chicago, IL.)

Sugihara R. T. (2000). Coqui trap study summary. USDA/APHIS/WS/NWRC, Hilo, Hawaii.

Thom, E. C. (1959). The discomfort index. Weatherwise 12, 57–59.
U.S. Environmental Protection Agency (1992). R.E.D. Facts: Citric Acid. EPA-738-F-92-017.

van Gelder, J. J. , and Strijbosch, H. (1996). Marking amphibians: effects of toe clipping on Bufo bufo (Anura: Bufonidae). Amphibia-Reptilia 17, 169–174.
| Crossref | GoogleScholarGoogle Scholar | Wolfe E. W. , and Morris J. (1996). Geologic map of the Island of Hawaii. U.S. Geological Survey miscellaneous geologic investigations series map I-2524-A, scale 1 : 100 000. (USGS: Honolulu.)

Woolbright, L. L. (1985). Patterns of nocturnal movement and calling by the tropical frog Eleutherodactylus coqui.  Herpetologica 41, 1–9.


Woolbright, L. L. (2005). A plot-based system of collecting population information on terrestrial breeding frogs. Herpetological Review 36, 139–142.


Woolbright, L. L. , Hara, A. H. , Jacobsen, C. M. , Mautz, W. J. , and Benevides, F. L. (2006). Population densities of the coqui, Eleutherodactylus coqui (Anura: Leptodactylidae) in newly invaded Hawaii and in native Puerto Rico. Journal of Herpetology 40, 122–126.
| Crossref | GoogleScholarGoogle Scholar |