Chemical control of the invasive Jackson's chameleon (Trioceros jacksonii xantholophus) in Hawaii

ABSTRACT

Invasive reptiles cause global ecosystem damage and are difficult to control once established. Visual detection and manual capture are time consuming and largely ineffective at eradication, particularly for cryptic species. The Jackson's chameleon (Trioceros jacksonii xantholophus), native to eastern Africa, is popular in the global pet trade and has become established in several localities, including the Hawaiian Islands where it has escaped or been intentionally released into sensitive native forest habitat where it feeds on endangered species. Here we tested an orally delivered, chemical toxicant as a feasible management technique for this invasive lizard in Hawaii. We administered predetermined dosages of powdered acetaminophen to adult chamleoens and determined that the dosage necessary to achieve ≥95% mortality within 48 h across size classes was 2000 mg/kg, or 90 mg of acetaminophen for an adult average mass of 45 g. Since the liver is known to process acetaminophen in vertebrate taxa, we conducted post mortem histological examination of liver tissue for all specimens at the 48 h time point. Finally, we propose a testable mechanism for field delivery of this oral toxicant following behavioral trials.

KEYWORDS:

• Conservation biology
• nonnative species management
• acetaminophen
• Pacific island conservation
• invasive herpetofauna

Acknowledgments

We would like to thank Vince Costello and Jamie Tanino of the Oahu Army Natural Resources Program for providing specimens, and Thomas Arthur-Hooper Smith, Marat Khramov, and Elysse Forester (UHM) for laboratory assistance. We are grateful to Myoko Bellinger at the John A. Burns School of Medicine and Dr Kassie Cole, Dr Masato Yoshizawa and Jessica Maxfield (UHM) for microscope use and assistance. For intellectual input and helpful comments regarding experimental design, we would like to thank Dr Shane Siers (USDA), Dr Robert Reed (USGS), Dr Nicholas James (UHM), and Brad Hann (UHM).

Disclosure statement

All experiments conducted during this study comply with federal and state legal requirements. The research has been reviewed and approved by the Institutional Animal Care and Use Committee at the University of Hawaii under protocol #15-2128. Additionally, all animals were collected under the permit # ODF-011316R, from the State of Hawaii Department of Land and Natural Resources. No financial interests or benefits will result from the applications of this research.