Aesthetic Aliens: Invasion of the Beauty Rat Snake, Elaphe Taeniura Cope, 1861 in Belgium, Europe

We report on an established population of the beauty rat snake, Elaphe taeniura Cope, 1861, a large, oviparous colubrid native to Southeastern Asia, in Belgium. The snakes have invaded a railroad system next to a city in the northeast of the country. Our report is based on validated citizen science observations, supplemented with directed surveys. The species has been recorded in the wild since 2006, most probably following an introduction linked to the pet trade. Genetic identification, based on the COI gene, confirms that the sampled individuals belong to E. taeniura. In addition, the snakes recorded in Belgium phenotypically match E. t. taeniura, a Chinese subspecies. Exact date of introduction, invasion extent and population size are currently unknown, but the number of observations has increased in recent years. Sightings exist from an area of 208 km(2), yet the core distribution is estimated to be no more than 2 km(2). Based on what is currently known on its ecology and distribution, we estimate that the species represents medium environmental risk. However, the species' distribution and invasive potential in Belgium remain largely unknown. As management of more widely established snake populations is notoriously difficult, we advocate a rapid response as the most appropriate risk management strategy.