Figure 4: Observed feedback at the population level. (a) Established dense pioneer black poplar cohort with a very high growth rate on a gravel bar of the Garonne River; (b) same cohort in winter, with well-distinguishable massive sediment trapping in the vegetation unit. Photographs: Dov Corenblit.
Community-level feedbacks: responses and effects of biodiversity on the functioning of riverine ecosystems
At the community level, riparian vegetation can decisively modulate fluvial dynamics, and in return, adjusts its structure (floristic composition, physiognomy and mean trait value) to new environmental configurations evolving under biotic control according to characteristic resilient succession patterns. Research carried out on the Tech and Allier Rivers permitted to identify, at the community level, a number of key elements of the abiotic-biotic feedback which control the structure and functioning of riverine ecosystems in different and more or less artificialized hydrogeomorphological contexts. As suggested by Tilman (1996), Loreau et al. (2001; 2021) and Hooper et al. (2005), our investigations showed that the diversity of response and effect traits of engineer organisms influences the functioning and stability or resilience of the ecosystem (Fig. 5).