Searching the keys of invasiveness on islands: a phylogenomic and functional approach in the family Asteraceae

Abstract

Invasive species are recognized as one of the key drivers of global biodiversity loss. Oceanic islands harbor a fragile and unique biota that make them especially vulnerable to invasive species. However, the factors behind the invasive success of certain species remain uncertain. Charles Darwin proposed two opposing hypotheses to predict the species invasive potential, known as the Darwin’s Naturalization Conundrum (DNC). First, the “pre-adaptation hypothesis” proposes that species closely related to the native community have similar characteristics that make them pre-adapted to establish and spread under the same local environmental conditions. Alternatively, the “naturalization hypothesis” predicts that species distantly related to native species can exploit empty niches and avoid competitive exclusion, having a higher invasive potential. These two hypotheses, which rely on environmental and biotic filters respectively, can contribute to determine invasive success. In practice, the study of the DNC can be addressed by assessing two different dimensions of relatedness between species: phylogenetic and functional relatedness. In this talk we present the project ASTERALIEN that aims to test the DNC in the Compositae family, the most species-diverse plant family in the Canary Islands. From a phylogeny that includes all the genera and most of the species present in the archipelago, we estimated the phylogenetic relatedness between alien (invasive and non-invasive) and native species. In addition, functional traits were measured from all the species collected in the field and functional distances were calculated between alien and native species. Integrating both phylogenetic and functional approaches, it allows us to explicitly assess the invasive potential of alien species of the Compositae family under the framework of the DNC.