Recent channel adjustments and riparian vegetation response: Some examples from molise (Italy)

An integrated geomorphological and ecological approach was adopted
to investigate the relation between recent channel adjustments and riparian
vegetation evolution by performing a large-scale multi-temporal
analysis of channel and land cover features and a study of the present-day
floristic setting along the three major river systems present in Molise
(Southern Italy), the Volturno, Biferno and Trigno. Our results highlight
the major channel adjustments that occurred between 1954 and 2009
consisting in progressive morphological changes, extreme channel narrowing
(between 84% and 97%) and moderate to very intense channel
incision (between 2 and 10.5 m). These channel adjustments led to the
progressive stabilization of most of the formerly active channel systems
and were accompanied by substantial changes in the riparian vegetation
which now appears largely, but not completely, in equilibrium with the
present river dynamics. Major differences may be noted between the
studied river reaches in relation to their state of naturalness, floristic richness
and differentiation in vegetation types, which appear particularly
controlled by the amount of channel incision and human disturbance.
Our findings underline the importance of fluvial dynamics and trends in
controlling the development and structure of riparian vegetation and the
connected ecological status of river systems.