Figure 2: Multi-scale theoretical model of the feedback between
riparian vegetation dynamics and river morphodynamics.
Individual plant and population level feedbacks: response and
effect traits of Populus nigra
In settings exposed to high tractive forces and sediment erosion or
burial during floods, high temperatures and hydric stress during summer
low flows, such as on alluvial bars, the completion of the life cycle of
certain woody pioneer riparian species such as P. nigra requires
a progressive modification of hydrogeomorphological conditions and
habitat, from germination to sexual maturity. The latter is reached when
the habitat and its topographic surface attain higher, more stable
levels, characterized by the deposition and accumulation of finer
sediments, nutrients, and organic matter, and less exposed to the risk
of destruction by floods.
Individual plants may form together at the colonization stage more or
less compact and monospecific woody populations which are very relevant
for the study of biogeomorphological feedback from the individual to
population levels. In riparian contexts in the European Northern
hemisphere, P. nigra has become a model species for field studies
but also ex situ experiments (Figs. 3 and 4).