Rehabilitation effects on gully sediment yields and vegetation in a savanna rangeland

Koci, Jack, Wilkinson, Scott N., Hawdon, Aaron A., Kinsey-henderson, Anne E., Bartley, Rebecca, and Goodwin, Nicholas R. (2021) Rehabilitation effects on gully sediment yields and vegetation in a savanna rangeland. Earth Surface Processes and Landforms. (In Press)

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Abstract

Gully rehabilitation can contribute to catchment management by stabilising erosion and reducing downstream sediment yields, yet the globally observed responses are variable. Developing the technical basis for gully rehabilitation and establishing guidelines for application requires studies that evaluate individual rehabilitation measures in specific environments. An eight-year field experiment was undertaken to evaluate sediment yield and vegetation responses to several gully rehabilitation measures. The rehabilitation measures aimed to reduce surface runoff into gully head cuts, trap sediment on gully floors and increase vegetation cover on gully walls and floors. The study occurred in a savanna rangeland in northeast Australia. Two gullies were subject to treatments while four gullies were monitored as untreated controls. A runoff diversion structure reduced headcut erosion from 4.3 to 1.2 m2 y-1. Small porous check dams and cattle exclusion reduced gully total sediment yields by more than 80 percent, equivalent to a reduction of 0.3–2.4 t ha-1 y-1, but only at catchment areas less than 10 ha. Fine sediment yields (silt and clay) were reduced by 7 and 19 percent from the two treated gullies, respectively. The porous check dam deposits contained a lower percentage of the fine fraction than the parent soil. Significant regeneration of gully floor vegetation occurred, associated with trapping of organic litter and fine sediment. Increases in vegetation cover and biomass were comprised of native perennial grasses, trees and shrubs. In variable climates, long-term gully rehabilitation will progress during wetter periods, and regress during droughts. Understanding linkages between rehabilitation measures, their hydrologic, hydraulic and vegetation effects and gully sediment yields is important to defining the conditions for their success.

Item ID: 66268
Item Type: Article (Research - C1)
ISSN: 1096-9837
Keywords: check dam; erosion; Great Barrier Reef; gully remediation; land degradation; soil and water conservation
Copyright Information: © 2021 John Wiley & Sons, Ltd.
Funders: Australian Government (AG), Queensland Government (QG), National Environmental Science Program (NESP), Australian Department of Defence, Meat and Livestock Australia (MLA), The Commonwealth Scientific and Industrial Research Organisation, University of the Sunshine Coast
Projects and Grants: AG/QG Paddock to Plate Program, NESP‐TWQ‐2.1.4 and 5.9, MLA Grant/Award Number: B.NBP.0546
Date Deposited: 25 Feb 2021 01:09
FoR Codes: 37 EARTH SCIENCES > 3709 Physical geography and environmental geoscience > 370901 Geomorphology and earth surface processes @ 50%
41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410405 Environmental rehabilitation and restoration @ 40%
41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410402 Environmental assessment and monitoring @ 10%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1806 Terrestrial systems and management > 180601 Assessment and management of terrestrial ecosystems @ 50%
18 ENVIRONMENTAL MANAGEMENT > 1806 Terrestrial systems and management > 180604 Rehabilitation or conservation of terrestrial environments @ 50%
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