The arrival of swimming snakes in the Balearics has sparked a new chapter in the ongoing battle against Balearic lizards. This development is particularly concerning as it marks a shift in the dynamics of the ecosystem. The presence of these snakes, which have been observed swimming from Ibiza to nearby islets, poses a significant threat to the already endangered Ibiza wall lizard population. The situation is dire, with the snakes rapidly colonizing the islands and preying on the lizards, leading to a drastic decline in their numbers. The horseshoe whip snake, a non-venomous reptile, has become an existential threat to the lizards since its appearance on the island two decades ago. The snakes' rapid colonization can be attributed to the import of ancient olive trees by wealthy property owners, which have provided ideal travel berths for hibernating snakes and snake eggs. The snakes' thriving population on Ibiza has led to specimens over 2 meters long and weighing 2.5 times more than their peninsular counterparts. The biologist Oriol Lapiedra highlights the increasing competition for food among the snakes as a potential driver for their migration to islets. The damage has already been done, with researchers observing a drastic decline in lizard populations on Santa Eulària, from 72 in 2016 to just three in 2023. The unique lizard populations of 10 islets have become extinct, taking with them thousands of years of unique evolution. The situation is dire, with forecasts suggesting the snakes will be found across 100% of the island by the end of 2027. The small size of the islets and the voracity of the snakes leave little room for optimism. Lapiedra draws parallels to the Pacific island of Guam, where the brown tree snake led to the extirpation of 10 of 12 native forest bird species. However, there is a glimmer of hope. The safest lizard populations in Ibiza are now found in urban areas, where the snakes are often run over or killed by people. Lapiedra emphasizes the rapid disappearance of the lizards as both an ecological and cultural disaster, with the loss of unique lineages being a tragedy akin to a fire in an old church. The situation calls for urgent action to protect the lizards and prevent further ecological and cultural damage.
