Online trading tools as a method of estimating propagule pressure via the pet-release pathway

What is it about?

The deliberate or accidental release of pets is an important pathway by which exotic species are often introduced into new environments, often with negative effects on the local species and ecosystems. Internet trading sites were used to determine the spatial distribution and magnitude of propagule pressure of red-eared slider turtles (RES; Trachemys scripta elegans) within the New Zealand pet trade. Sites were tracked daily for two years (2007-2009) and information on age, sex, season, and location was recorded. More than 1,500 sales and 80 reports of lost/found RES were recorded. Unsurprisingly, the highest number of sales and lost/found RES was in Auckland, the region with the highest human population. Female slider turtles were more often reported as lost or found than males, despite a similar sex ratio of sales. The type and quality of information gathered in this manner is not perfect, as it only provides an estimate of minimum numbers of animals that are being traded/lost into the environment, but nonetheless, it provides useful data when planning a management or eradication plan for feral turtles in New Zealand.

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Why is it important?

Our results highlighted areas where turtles were most often accidentally released in New Zealand (Auckland), which was also an area predicted to be the most climatically-suitable for this species. Monitoring online sales of exotic species provides useful demographic information, as well as an indication of propagule pressure via the pet-release pathway. This technique is applicable to other species and may be a useful tool to help determine locations at risk of the establishment of other exotic species.