How do invasive plant species impact ecosystem functioning? A functional trait and spectranomics based approach using the case of two reciprocal invaders

Exotic species invasion has been recognized to be among the major causes of global biodiversity loss. Surprisingly, however, only little systematic research has been performed so far on the effects of species invasion on ecosystem functioning. We currently do not know when invasive species can be expected to cause ecosystem changes, and which ecological processes are triggering these changes. Ecosystem functions are believed to be effectuated by the functional trait set of the species that make up these ecosystems. For plants, these functional traits can be defined as morphological, physiological and phenological features that interact with the biotic and abiotic environment. The general objective of this proposal is to study the effects of species invasion on ecosystem functioning, and to identify the functional traits that are responsible for these changes. Since the traditional plant functional trait approach has several drawbacks, I will explore the added value of spectral approaches to define relevant trait sets. Indeed, recent developments in hyperspectral spectroscopy technology allow fine-scale observations of light spectra reflected by plant species, opening up alternative ways to identify individual species and their functional trait suits.