Landscape Genomics and Niche dynamics of hybrid invasive alien plants (GENNIAlien)
Invasive Alien Species (IAS) have become very important components of the floras and faunas across the world, being regarded as one of the main drivers of native species extinctions. Understanding the biological processes that underlie invasion is critical to effectively manage current invaders and to prevent future invasions. Among the possible evolutionary pathways leading to invasiveness, hybridisation is one of the most interesting and least well understood. Certainly, some of the most dangerous IAS are the product of hybridisation processes, highlighting the central role of this evolutionary mechanism in invasion success. Hybridisation has proven to contribute to the success of invasiveness thanks to increased fitness or adaptive evolution (in most cases, to new ecological niches), which can be the result of several genetic and genomic processes.In recent years, some studies have already reported the role played by hybridisation in providing a larger pool of genetic diversity, counteracting the disadvantages of strong bottlenecks linked to the invasion process. In contrast, the potential effect of structural variation at the genomic level in the rapid adaptation of hybrid taxa is a promising but still understudied field of research. The main hypothesis of our project proposal (GENNIAlien) is that genomic structural changes in hybrids such as changes in ploidy level, chromosomal rearrangements or expansion/reduction of transposable elements (TE) drive the appearance of additional evolutionary novelty and diversity, leading to an enhanced invasion capacity. As models to test this hypothesis, we are using two widespread species systems that invade Mediterranean ecosystems: the Carpobrotus edulis-acinaciformis and the Kalanchoe x houghtonii complexes. Both groups represent contrasting examples of homoploid and polyploid hybridisation, where previous evidence already indicates that genomic structural variation is contributing to their invasion capacity.By applying the latest methodological approaches to explore landscape genomics and niche dynamics in these two species systems, we will be able: (i) to disentangle the number and timing of introductions, as well as to track their history of hybridisation events; (ii) to test whether the effects of hybridisation on the genomic structure of individuals including changes in ploidy level, chromosome rearrangements and TE dynamism contribute to the evolution of invasiveness; and (iii) to see whether genetic and genomic changes in hybrid invasive plants imply niche shifts, as well as to unravel how these would affect invasion success under several scenarios of climate change. In this sense, GENNiAlien will expand the frontiers of knowledge of invasion biology and evolutionary biology, two fields of study that are increasingly important in the context of the current climate and biodiversity crisis.