"The lizard used to be impossible to miss in the countryside or in the city. Now, it’s all but disappeared"

What does the wall lizard represent for Ibiza and the Balearic Islands?

The lizard is more than just a symbol of the island. People have always lived with it close by: it used to be impossible to go out into the countryside or walk through the city without seeing it, because it lived everywhere. This close relationship is captured in the stories, drawings, ornaments and souvenirs that tourists take home with them. But in terms of biodiversity, it’s even more important: it’s the only truly native land vertebrate, here even before humans. This species has also been able to adapt to all the changes over time, performing a unique ecological role. Our lizard pollinates flowers, feeds on fruit and spreads seeds. In fact, there are plants that wouldn’t be able to reproduce without it, so if the lizard disappears, so will some plant species.

What’s the current situation like?

Until the early 2000s, it was excellent. Everything changed when, around 2002 or 2003, snakes were introduced along with olive trees brought from the mainland for gardens. Three species came, but one species in particular is causing a real catastrophe: the horseshoe snake. Today, it can be found on 90% of the island, and has caused the lizard to completely disappear in rural areas. This is the case in more than 60% of the territory: when you go to the countryside, you don’t see a single one. There are only small patches left in some urban areas and a small strip of the island where both species still exist together, but it seems the lizard will eventually disappear there too, as they're the main food source for these snakes. The situation is dire.

And what was it like before the snakes invaded?

Before, the lizard could be found everywhere. It was impossible to go out in the countryside or to the beach and not see dozens of them. They had an extremely high population density, with thousands per square kilometre. They would even come up to you while you were having a snack in the countryside, or on the beach and try to steal your sandwich. Today, that’s all gone. Where the snake goes, the lizard has no escape: it’s never had a natural enemy on the island, and so hasn’t developed any defence or escape mechanisms, meaning it’s extremely easy to hunt. For a few years they were able to coexist, but now it seems the lizard will soon disappear.

Are we talking about a real risk of extinction?

Yes, absolutely. There are no more lizards across 60–70% of Ibiza. There may still be populations in urban environments, where the population density of snakes is somewhat lower, but even in places like Jesús, Ibiza Town and Santa Eulària, snakes have already been spotted, which suggests the invasion is severe and there are no natural enemies to stop it. Formentera has adopted a different strategy: there, they’re trying to corner the snake so that the lizard can regain ground. But in Ibiza, the scenario is very complicated.

Why's it so difficult to control these invasive species?

Because they get here due to ineffective controls. The regulation of the free market and entry of goods at ports is very weak. Nobody checks the contents of a box of bananas from Costa Rica or what might be in an olive tree brought from the mainland. And when an animal arrives in a new ecosystem without natural predators, it’s very easy for it to spread. Sometimes the opposite happens: some invasive species fail to adapt and disappear on their own, but about 10% manage to settle and become pests. It happened in Ibiza in the 1970s with the pine processionary, and again in the 2000s when it arrived in Formentera. The same thing has happened with snakes.

What’s been the role of projects funded by sustainable tourism tax?

They’ve been essential. Neither the control attempts in Ibiza nor the recovery attempts in Formentera would be possible without the tourism tax. This is where the vast majority of the budget comes from, as it would be impossible to sustain these programmes with regular government support. In Ibiza, however, the results are not enough: the species is still dying out at great speed. It’s tragic to watch it disappearing from our island without being able to stop it. More funding is needed, and above all, a clear, coordinated action plan that spells out exactly what to do and how we can help.

Does public awareness also play an important role?

Yes, from the outset. People have been highly involved. There are citizen platforms that support the Balearic Island Wildlife Recovery Centre (COFIB), hand out traps and organise training. As well as the thousands of official traps funded by sustainable tourism tax, there are at least three to four times as many put out by private individuals. Civil society is working hard to try to save the lizard, and this has been crucial.

How do you see the future of the wall lizard in Ibiza?

I’d like to think that we’ll be able to maintain a minimum viable population, and that in 20 years we’ll see lizards in the countryside again. But I’m increasingly pessimistic. We may be able to save the species itself, but not all subspecies and varieties from the islets. The horseshoe snake can swim and has already reached some of the islets of Mallorca and Ibiza. If it continues to colonise further, it’ll wipe out endemic subspecies that we’ll never be able to recover. Our response may have come too late, and the situation may get even worse than it is now.