Fluvial biogeomorphological feedbacks from plant traits to the
landscape: lessons from French rivers in line with A.M. Gurnell’s
influential contribution
Abstract
Research in fluvial biogeomorphology largely aims to promote our
understanding of the interactions between riparian vegetation and
fluvial morphodynamics within riverine ecosystems. Starting at the end
of last century, Angela M. Gurnell has made a major contribution to
fluvial geomorphology by considering, in addition to water flow and
sediment transport, explicitly riparian, and later also aquatic
vegetation and thus significantly promoted the fluvial
biogeomorphological approach from its beginnings until today. The
objective of the present paper is to present a set of studies and
results obtained over the last twenty years by the authors and many
collaborators, including Angela M. Gurnell, on a panel of French rivers:
Tech, Garonne, Isère and Allier Rivers. In particular, feedback
mechanisms between fluvial morphodynamics and riparian vegetation
dynamics were investigated directly in the field and also using high
resolution remote sensing at the scale of individual plants,
populations, communities and landscapes, as well as during
semi-controlled ex situ experiments at the scale of individual
plants. Collectively, the authors’ research conducted over the past 20
years contributed to elucidate some key aspects of the feedback dynamics
between the lowest and highest levels of the riparian ecosystem
organisation. This article presents and discusses those key aspects. The
gradually obtained results contributed to better understand and quantify
feedbacks between river morphodynamics and vegetation at nested
spatiotemporal scales, from plant species traits to the riverine
landscape. Furthermore, the biogeomorphological approach advocated for
more than twenty years now, has clearly helped to contribute to the
enlargement of the discipline of geomorphology to ecology as well as
evolutionary ecology, and to the development of a more integrative
vision to study earth surface processes.