Determinants of island ecological complexity in the context of global change

Biodiversity is declining globally at an unprecedented rate. Representing ~30% of the biodiversity hotspots, islands are particularly vulnerable to anthropogenic activities, indeed 80% of reported extinctions are island species. Yet, unique island biodiversity – which includes not only the species but also the myriad of interactions among them – is still greatly unknown. It is thus urgent to describe it and forecast the consequences of its annihilation so we can mitigate the effect of further losses. Detecting ecological interactions and understanding their complexity is, however, one of the big challenges in the natural sciences. The advent of new theories and analytical tools, such as critical transition theory and complex network analysis, provides hope to reach that goal. As relatively simple systems with well-defined borders, islands have a great potential to advance our comprehension of nature complexity. IslandLife will provide the most comprehensive and quantitatively sophisticated study of multilayer networks to date in any terrestrial ecosystem. We will focus on five archipelagos encompassing four oceans and a wide latitudinal gradient, comparing for the first time the food web structure of ‘pristine’ (little-disturbed) islands (of a few km2) with areas of similar size in nearby disturbed (human-inhabited) islands. The objective is to unveil the unique biodiversity of these ecosystems, understand their complexity, and evaluate their fragility to global change drivers, such as biological invasions. We will combine direct observations during intense fieldwork, automated-video monitoring and deep-learning, cutting-edge molecular techniques, and newly developed coextinction models to predict persistence and resilience of island biota to disturbances. The project will represent a major breakthrough towards understanding the effects of global change on these valuable ecosystems, of great relevance to both theoretical ecologists and applied conservationists.