FearIsland
National Projects
Project duration: 
Oct 2022 to Oct 2025

Biological invasions wreak havoc on biological communities on islands. The Mediterranean is no exception. In this project we study an invasion of snakes on the island of Ibiza that is rapidly spreading and threatens the viability of the populations of a key species: the lizard of the Pitiuses and, consequently, the viability of the entire Mediterranean ecosystem. The project includes studies on cascading consequences as well as the study of rapid changes in the behavior and morphology of the lizards.

Introduction

The role of behavior in evolution remains one of most controversial issues in evolutionary biology. Consequently, the evolutionary dynamics of adaptive behaviors and the consequences of these dynamics for the functioning of biological communities and for the persistence of animal populations in a rapidly changing world remain virtually unknown. The overarching objective of this proposal is to conclusively examine the ecological and evolutionary consequences of ‘island tameness’ (the adaptive loss of effective anti-predatory behaviors on island populations) in a context of rapid environmental change. To fill this gap, our team will study wild ranging populations of endemic lizards in the Mediterranean as well as worldwide patterns of species extinction in a cosmopolitan bird clade. 

In Ibiza, we will take advantage of a unique ‘natural experiment’ to carefully investigate predator-driven behavioral evolution by natural selection in endemic lizards in the context of a recent, rapidly spreading predatory snake invasion. We have already identified a series of replicated sites where snakes are coexisting with native lizards and others where these new predators are not present. We will compare the phenotypes and genomes of lizards in these two different predation regimes by using high-resolution morphological profiling and innovative behavioral assays to examine risk-taking behavior. Then, we will combine these with cutting-edge genomic tools, novel molecular techniques and a recently refined theoretical framework on the ecological relevance and evolutionary potential of inter-individual variation in behavior. This will allow characterizing potential phenotypic shifts of native lizards in response to the novel predator (OBJ 1) as well as identifying the genetic basis of such differences (OBJ 2). In this project, we aim at obtaining an integrative perspective of the consequences of predator invasion, from the genetic modifications to the ecosystem level alterations caused by these invasions. With that objective, we will characterize arthropod communities on invaded vs. noninvaded sites as well as on a third category, which correspond to sites where the invasive snakes have apparently extirpated local populations of lizards. Either the absence of lizards or changes in their foraging niche could entail modifications of the biological interactions of this keystone species with their prey. This is particularly important given that Ibiza wall lizards are the only dispersers and pollinators of at least two plant species. Therefore, changes in their foraging niches could entail the deterioration of ecosystem functioning. Our aim is to assess the downstream cascading consequences of behavioral shifts for ecosystem functioning (OBJ 3). 

Finally, we will adopt a global perspective to examine whether and how the evolution of traits that make species thrive on islands (the ‘island syndrome’) is paradoxically the main reason for their extinction when confronted with rapid environmental changes (OBJ 4). We will test this hypothesis using the cosmopolitan bird clade (pigeons and doves) and high-quality data on recent extinctions exists. 

Overall, our integrative approach will effectively advance the state-of-the-art of adaptive diversification theory by incorporating the role of behavior in the first stages of evolutionary adaptation to new selective pressures, a question of major relevance in the current context of human-induced rapid environmental change.