Title: Vegetation and topographic controls on sediment deposition and storage on gully beds in a degraded mountain area
Authors: Molina Verdugo, Armando ×
Govers, Gerard
Cisneros, Felipe
Vanacker, Veerle #
Issue Date: May-2009
Publisher: Wiley
Series Title: Earth surface processes and landforms vol:34 issue:6 pages:755-767
Abstract: Active gully systems developed on highly weathered or loose parent material are an important source of runoff and
sediment production in degraded areas. However, a decrease of land pressure may lead to a return of a partial vegetation cover,
whereby gully beds are preferred recolonization spots. Although the current knowledge on the role of vegetation on reducing
sediment production on slopes is well developed, few studies exist on the significance of restoring sediment transport pathways
on the total sediment budget of degraded mountainous catchments. This study in the Ecuadorian Andes evaluates the potential
of vegetation to stabilize active gully systems by trapping and retaining eroded sediment in the gully bed, and analyses
the significance of vegetation restoration in the gully bed in reducing sediment export from degraded catchments. Field
measurements on 138 gully segments located in 13 ephemeral steep gullies with different ground vegetation cover indicate that
gully bed vegetation is the most important factor in promoting short-term (1–15 years) sediment deposition and gully stabilization.
In well-vegetated gully systems ( ≥ 30% of ground vegetation cover), 0.035 m³ m–1 of sediment is deposited yearly in the gully
bed. Almost 50 per cent of the observed variance in sediment deposition volumes can be explained by the mean ground
vegetation cover of the gully bed. The presence of vegetation in gully beds gives rise to the formation of vegetated buffer zones,
which enhance short-term sediment trapping even in active gully systems in mountainous environments. Vegetation buffer zones
are shown to modify the connectivity of sediment fluxes, as they reduce the transport efficiency of gully systems. First calculations
on data on sediment deposition patterns in our study area show that gully bed deposition in response to gully bed revegetation
can represent more than 25 per cent of the volume of sediment generated within the catchment. Our findings indicate that
relatively small changes in landscape connectivity have the potential to create strong (positive) feedback loops between erosion
and vegetation dynamics.
ISSN: 0197-9337
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Division of Geography & Tourism
× corresponding author
# (joint) last author

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