Timor-Leste: preliminary assessment of a rapidly eroding landscape in the Coral Triangle

R. J. Wasson; A. L. Amaral; J. Rouwenhorst; K. Fifield; N. Chauhan; T. Pietsch; D. M. Alongi; F. Tirendi; A. K. Singhvi

doi:10.1071/MF24156

RESEARCH ARTICLE (Open Access)

Previous Next Contents Vol 75(17)

Timor-Leste: preliminary assessment of a rapidly eroding landscape in the Coral Triangle

R. J. Wasson

^A ^B ^* , A. L. Amaral ^C , J. Rouwenhorst ^D , K. Fifield ^E , N. Chauhan ^F , T. Pietsch ^G , D. M. Alongi ^H , F. Tirendi ^I and A. K. Singhvi ^F

+ Author Affiliations

- Author Affiliations

^A College of Science and Engineering, James Cook University, Cairns, Qld 4232, Australia.

^B Fenner School of Environment and Society, Australian National University, Canberra, ACT 0200, Australia.

^C Ministry of Agriculture, Livestock, Fisheries and Forestry, Dili, Timor-Leste.

^D Research Institute for Environment and Livelihoods, Charles Darwin University, Darwin, NT 0815, Australia.

^E Department of Nuclear Physics, Australian National University, Canberra, ACT 0200, Australia.

^F Physical Research Laboratory, Ahmedabad 380009, India.

^G Griffith Centre for Coastal Management, Griffith University, Brisbane, Qld 4222, Australia.

^H Tropical Coastal and Mangrove Consultants, Pakenham, Melbourne, Vic. 3810, Australia.

^I Australian Institute of Marine Science, Townsville, Qld 4810, Australia.

^* Correspondence to: wasson.robertj@gmail.com

Handling Editor: Max Finlayson

Marine and Freshwater Research 75, MF24156 https://doi.org/10.1071/MF24156

Submitted: 9 July 2024 Accepted: 25 October 2024 Published: 18 November 2024

© 2024 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Context

Sedimentation in the rivers and on the coasts of Timor-Leste has increased since deforestation, affecting floods and probably living aquatic resources.

Aims

To provide scientifically based estimates of long-term and short-term erosion rates to assess the apparent role of deforestation, a topic that has not received sufficient quantitative attention in the Coral Triangle.

Methods

Short-term erosion rates have been estimated from regional relationships between river sediment yield and catchment areas and cosmogenic nuclides for long-term rates. An attempt has also been made to estimate changes in rates of delta progradation to determine whether recent increases have occurred following deforestation.

Key results

The major scientific finding is that reduction in vegetation cover for agriculture and timber harvesting, particularly in the mountains, increased sediment yield by factors up to 120, mainly by landsliding. And there has been a large amount of sediment exported to the delta and offshore from river-channel change.

Implications

Impacts on living resources are likely both in rivers and on the coast, but require assessment. Revegetation of hillslopes is likely to reduce these impacts and improve the livelihoods of local people.

Keywords: Coral Triangle, deforestation, erosion, floods, land cover, living resources, sedimentation, Timor-Leste.

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