Geographical variation of aquatic macrophyte biodiversityTowards an integration of scale and ecological organisation

Resum

The main aim of this thesis was to examine patterns and mechanisms of aquatic macrophyte diversity at regional and global scales using distinct organisation levels, from genes to species. Specifically, we (i) established a novel combination of robust mathematical methods capable of identifying the processes –including biotic interactions– and most important spatial scales involved in community assembly; (ii) built several phylogenies comprising most aquatic plant lineages and exploited a wide array of functional traits to determine whether different diversity facets (i.e. taxonomic, functional and phylogenetic) explain idiosyncratic patterns of macrophyte species distributions that would otherwise be missed in a traditional analysis of community turnover; (iii) used microsatellite loci to explore the spatial genetic variation of the aquatic macrophyte Myriophyllum alterniflorum DC. and examine if the results obtained through molecular estimates match modern perspectives of metacommunity theory at regional scales; and (iv) retrieved regional data from six continents to untangle if macroecological processes have left a footprint in the current patterns of compositional variation and community–environment relationships of aquatic macrophytes at global scales