Data from: The hydrochorous dispersal of plant propagules in a giant river reservoir: implications for restoration of riparian vegetation

The riparian vegetation of many rivers around the world is impacted by
flow regulation for hydropower. Water levels behind dams are being raised
to generate electric energy, forming river reservoirs. River regulation
has a large impact on the riparian vegetation which influences both the
adjacent aquatic and terrestrial ecosystems. Therefore, restoration of
degraded riparian vegetation in river reservoirs has been of increasing
research interest. Propagules dispersed from connected tributaries via
water (hydrochory) are considered a vital source for the recovery of
riparian vegetation in regulated rivers. However, the hydrochorous
dispersal of plant propagules in river reservoirs is unclear. We explored
the dispersal distance and deposition patterns of hydrochorous propagule
mimics in three tributaries that are regulated by the Three Gorges
Reservoir (TGR) in China. In eight out of nine release experiments, 95% of
propagule mimics were found within 3 km downstream from the release
points. Cumulative wind speed was the most important factor affecting the
dispersal distance of propagule mimics in the TGR. However, the dispersal
distance of propagule mimics was not significantly affected by water-level
variation and channel sinuosity. Variations in water level strongly
affected the deposition pattern of propagule mimics, with only 6.6% of the
propagule mimics stranding on the riparian zones under raised water level
and 83.8% stranding under declined water levels. The majority of stranded
propagule mimics were deposited at gentle slopes (0‒20°). Synthesis and
applications. Our results suggest that the majority of propagules that
enter river reservoirs via water would be retained within the first few
kilometers. Wind and water level variation are the main factors
determining the dispersal distance and deposition pattern of propagules.
Our findings have applications for riparian vegetation restoration in
river reservoirs. The vegetation in steep riparian zones distant from
free-flowing tributaries should be the priority for restoration actions
because these areas receive limited hydrochorous propagules. The plant
biodiversity and hydrological connectivity of connected tributaries, which
is an important propagule sources for riparian vegetation along river
reservoirs, should be protected. The seasonal dominant wind pattern should
be considered when evaluating the importance of tributaries as the source
of hydrochorous propagules for river reservoirs.