Spatial and temporal characteristics of soil erosion and identification of source contributors of sediments in the tropical rainforest region of Borneo

ABSTRACT

Soil loss, erosion vulnerability and source contribution of sediments from the severely logged rainforest region of the Baram River basin, Borneo, were characterized for three periods over the past 25 years: 1991–1994 (T1), 2006–2007 (T2) and 2015 (T3). A geographical information system (GIS) was used to estimate the Revised Universal Soil Loss Equation (RUSLE) and sediment source determination. Maximum annual soil loss varied from 483 and 671 t ha⁻¹ year⁻¹ in T1 and T2, respectively, to 1312 t ha⁻¹ year⁻¹ in T3. Soil erosion vulnerability shows a significant increasing trend between T1 and T2, subsiding by T3, as reflected in the percentage area of high erosion vulnerability zones (T1 < T2 > T3). Development of logging roads in the region increased significantly during the period and was identified as the source contributor of sediments. Zones of high soil loss are more closely controlled by barren land, logging roads and shifting agricultural practices than by any other type of land use, and this indicates the need for better restoration methods to reduce overall soil loss.

KEYWORDS:

• rainforest
• logging
• soil erosion
• vulnerability
• sediment source

Editor S. Archfield Associate editor J. Rodrigo-Comino

Editor S. Archfield Associate editor J. Rodrigo-Comino

Acknowledgements

The authors wish to thank Sarawak Energy Berhad for funding this research under the Project “Mapping of Soil Erosion Risk.” They also thank Curtin University Malaysia for facilities and other assistance and the Department of Irrigation and Drainage (DID), Malaysia, for providing rainfall data. The authors are also thankful to the anonymous reviewers and associate editor Dr. Jesus Rodrigo-Comino for their critical reviews, constructive comments and suggestions, which significantly improved the quality of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was carried out as part of the project “Mapping of Soil Erosion Risk” funded by Sarawak Energy Berhad (RD01/2014(C)), Malaysia.