Floodplain characteristics affect woody vegetation regeneration on point bars of a coastal plain river recovering from anthropogenic disturbances

Abstract

Floodplain characteristics contribute to the natural regeneration of vegetation and help facilitate their ecosystem recovery but vary within and between river systems and more so in a river system recovering from anthropogenic disturbances. Here, we explored the floodplain characteristics that contribute to the woody vegetation regeneration on point bars of the middle reach of the Apalachicola River in Florida, USA, which has been passively recovering for over two decades after dredging and disposal activities ended. Woody vegetation regeneration on point bars was analysed using 1999 and 2019 aerial imagery and divided into zones and sections. Data were extracted from a digitized geodatabase regarding several floodplain characteristics with potential to influence vegetation regenetation. Later, we analysed noncollinear floodplain characteristics using a random forest (RF) regression model. The top characteristics that contributed to the RF model include vegetation density, distance-toseeding source and bend curvature. Findings suggest that high vegetation density contributes substantially to woody vegetation regeneration. The negative relationship between distance-to-seeding source and vegetation regeneration shows the importance of seeding availability. The bend curvature corresponds with the highest regeneration in the lowermost section of point bars. Our results signify the importance of maintaining healthy vegetated corridors as a buffer to reinforce the vegetation community and potential seed source for passive recovery. These findings regarding floodplain characteristics can be applied to future active restoration of anthropogenically disturbed floodplains.

Remote sensing assessment of anthropogenic and climate variation effects on river channel morphology and vegetation: Impact of dry periods on a European piedmont river

“…Water levels and flood regimes affect riparian plant communities, eventually contributing to the establishment of riparian vegetation on floodplains and bars (Chen et al, 2023). Changes in the natural flow regime can therefore have a direct impact on plant communities.…”