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Beloit College

Publication Date

Spring 2006

Program Name

Australia: Sustainability and the Environment

Abstract

The cane toad (Bufo marinus) is a pest throughout Australia. Not only is it poisonous to native predators, it also consumes or out competes native fauna. It has only recently entered into Northern New South Wales where the site for this study is located, at Arakwal National Park. This study aims to discover the most effective method of cane toad eradication in the National Park.

Over the course of 18 days, three traps were set and rotated between 9 different sites. Traps were set at sunset and cleared at sunrise. The three traps used were; (1) Pitfall style trap by Mr. Paul Baker, winner of the Northern Territory trap competition, (1) two-gate Frogwatch trap, and (1) three-gate Frogwatch trap. The lights on the traps were connected to batteries that supplied constant light to attract bugs which in turn attract cane toads. In all seven toads were caught, five by the Pitfall trap and one each by the Frogwatch traps.

Ten of the 18 days were used for manual collection of eggs, tadpoles, metamorphs, and juvenile. One hour per day was spent for egg/tadpole collection and one hour for metamorph/juvenile collection. In egg/tadpole collections, no eggs and 2569 tadpoles were collected over the ten days. In metamorph/juvenile collections 176 were caught over the ten-day period. To compare the collections of egg/tadpole and juvenile/metamorph to toad trappings, high and low ranges for survival rates were applied to both collections.

Using the survival rates from the high end of the range, .04 expected adults were captured in tadpole collections and .22 in metamorph collections per hour of labor. The mean of adult toads caught with traps per half hour was .39. This shows that cane toad trapping was more effective based on overall expected adults caught. The variance of the distribution of each method was also calculated, resulting in that trapping adult toads had the least amount of variance over all.

Trapping adult toads was found to be most effective in cane toad eradication and also the most probable means of catching individuals. This study agrees with previous research that suggests the most effective measures of cane toad eradication target adult populations and not other life stages.

Disciplines

Biology | Environmental Sciences | Forest Sciences

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