Home > Explore Data & Reports > 2000 years of sustainable use of watersheds and coral reefs in Pacific Islands: A review for Palau


Koshiba, S., M. Besebes, K. Soaladaob, M. Ngiraingas, A.L. Isechal, S. Victor, and Y. Golbuu. 2014. 2000 years of sustainable use of watersheds and coral reefs in Pacific Islands: A review for Palau. Estuarine, Coastal, and Shelf Science, 144:19-26. https://doi.org/10.1016/j.ecss.2014.02.006

Data/Report Type:

Sponsored Research


In Palau and everywhere in the world, coastal coral reefs are threatened by sedimentation resulting from land clearing in the watersheds. Palau's largest island of Babeldaob is particularly susceptible to significant erosion due to its steep topography, high rainfall, and highly erodible volcanic soil. Previous studies have shown the damaging impacts of sedimentation on coral reefs around Babeldaob Island. Related studies conducted in Micronesia have also documented that mangroves can trap about 30% of the fine eroded sediment from land. This paper examines the sediment trapping capability of cultivated wetlands, in particular taro (Colocasia esculenta) fields, which are natural wetlands used to grow taro, a main staple crop for the population. A 7-months long field study was undertaken to quantify the sediment accumulation rate for taro fields and to determine their sediment trapping efficiency. The results showed that the taro fields were able to trap on average 90% of sediment, therefore sheltering coastal coral reefs and their fisheries from the negative impacts of terrestrial runoff. Based on the results of this study, we suggest that the combined sediment trapping capacity of taro fields and mangroves helped reduce sedimentation on coral reefs around Babeldaob Island. This enabled human settlement for over 2000 years on a small Pacific Island with the main staple food being taro for starch and reef fish for protein.

Note to readers with disabilities: Some scientific publications linked from this website may not conform to Section 508 accessibility standards due to the complexity of the information being presented. If you need assistance accessing this electronic content, please contact the lead/corresponding author, Primary Contact, or nccos.webcontent@noaa.gov.

Explore Similar Data/Reports


NCCOS delivers ecosystem science solutions for stewardship of the nation’s ocean and coastal resources to sustain thriving coastal communities and economies.

Stay Connected

Sign up for our quarterly newsletter or view our archives.

Follow us on Social

Listen to our Podcast

Check our our new podcast "Coastal Conversations"