Oriol Lapiedra
Behaviour & Evolution
A world where invasion fuels evolution
On Ibiza, the native lizards are struggling to survive a rapid biological invasion that began less than two decades ago. Since the arrival of the horseshoe whip snake (Hemorrhois hippocrepis) through the importation of olive trees, populations of the endemic Podarcis pityusensis have disappeared from most of the island. What started as an accidental introduction has become one of the fastest ongoing reptile extinctions in Europe.
A real-time natural experiment on evolution and extinction
Biological invasions provide a unique opportunity to study evolution and extinction as they happen. By introducing strong and sudden selection pressures, they allow us to observe how species adapt, interact, or disappear. Revealing the mechanisms that shape biodiversity under rapid environmental change.
What
happened?
Ibiza, a predator-free island, experienced a dramatic ecological shift starting in the early 2000s with the introduction of the invasive Horseshoe whip snake (Hemorrhois hippocrepis). This rapidly spreading predator has decimated populations of the island’s endemic Ibiza wall lizard (Podarcis pytiusensis), driving them to near extinction. The presence of this invasive snake has not only threatened the survival of the lizards but has also triggered significant changes in the behavior, cognition, and morphology of the native species. These changes reflect a rapid evolutionary response to predation pressure, altering the ecological dynamics of the island.
In this project, we investigate the ecological and evolutionary consequences of this invasion, examining how both predator and prey are evolving in response to these novel environmental challenges, and the broader impacts on ecosystem functioning.
Major Questions
1. Invasion dynamics: How fast is the horseshoe whip snake expanding, and what ecoevolutionary dynamics determine its spread?
2. Rapid evolution: How are both lizards and snakes evolving in behavior, morphology, and genetics across the invasion gradient?
3. Ecological mechanisms: What ecological and demographic processes sustain the snake’s invasion and drive the collapse of native lizard populations?
4. Ecological cascades: How does the loss of lizards reshape food webs, pollination, and nutrient cycling across the island?
Major Findings
Why this works
matters?
This project provides a rare real-time view of how biological invasions unfold and evolve.
By documenting behavioral, genetic, and ecosystem-level changes as they happen, our work bridges ecology, evolution, and conservation, offering predictive insight into how quickly invasions can reshape biodiversity.
The results inform strategies to mitigate invasive predators on islands and highlight the fragility—and resilience—of island ecosystems under global change
People involved
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