Exotics are more complementary over time in tree biodiversity-ecosystem functioning experiments

Background and aims

The Biodiversity – Ecosystem Functioning (BEF) literature proposes that ecosystem functioning increases with biodiversity because of complementarity in resource use among species, associated with functional diversity. In this study, we challenge the trait-based ecology framework by comparing congeneric exotic (European) and native (North American) tree species showing similar resource-use functional trait values. The trait-based framework suggests that two functionally equivalent species should play similar roles in a community, resulting in similar interactions and performances. However, several studies showed that when growing in mixtures, exotic species that are functionally equivalent to native species benefitted from enemy-release, resulting in a reduced apparent competition. We hypothesize that exotic species should be more productive than native species because the exotic species benefit from reduced apparent competition due to enemy-release rather than fro...