Multimodal remote sensing of aquatic plant diversity

For their morpho-physiological peculiarities and phenotypic plasticity, aquatic plants occupy the extremes of the global vegetation spectrum and display contrasting patterns of diversity along ecological and geographical gradients. Monitoring of aquatic systems at various scales is limited by logistic constraints and costs. Remote sensing (RS) is an ideal candidate tool to quantitatively and efficiently assess aquatic vegetation, but potentials were so far hampered by sensor availability and features. With the technical developments of airborne and spaceborne platforms in the last decade and increasing operational uptake, ecologically significant applications of RS to aquatic vegetation have become a reality, e.g. for: i) mapping of plant species and communities (including diversity); ii) assessing their physiological and ecological status (e.g. spatial-temporal dynamics); and iii) estimating biophysical and biochemical parameters from spectral response (spectro-functional traits). A synoptic picture of intra- and inter-specific variability of aquatic plants derived from RS allows to scale up from functional traits and community assembles to ecosystem processes, advancing functional ecology studies in aquatic systems in unprecedented ways. This work will provide theoretical background and an overview of state-of-the-art, practical examples of RS of aquatic plants, covering leaf to canopy and ecosystem scales, highlighting both capabilities and gaps still to be filled.