Abstract
Sedimentation is one of the biggest threats facing coral reefs, not only in Palau, but everywhere in the world where there are reefs within reach of river plumes. Due to Palau’s largest island of Babeldaob’s steep topography, high rainfall, and highly erodible volcanic soil, erosion has been exacerbated by recent increases in land-use. Studies have documented the negative impacts of the resulting sedimentation on coral reefs around Babeldaob. Similar studies have shown that mangroves can trap about 30 % of the fine eroded sediment from land. This paper documents the filtering effects of cultivated wetland, namely that of taro (Colocasia esculenta) fields, which are natural wetlands used to grow taro, a source of starch for the population. A 4-month long field study was conducted to quantify the sediment accumulation rate for three different types of taro fields and to determine their sediment trapping efficiency. The results showed that the taro fields have the capacity to trap up to 90 % of sediments. We suggest that the sediment trapping capacity of mangroves and taro fields mitigated the negative impacts of soil runoff on coral reefs around Babeldaob while the island was being inhabited by early Palauans for many generations.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Athens JS (2011) Paleoenvironmental contributions. In: Liston J (ed) Archaeological monitoring and emergency data recovery for the Compact Road, Babeldaob island, Republic of Palau. Historic preservation investigations, Phase III. Volume XII: lab analyses, discussion, syntheses. Prepared for US Army Corps of Engineers, Pacific Ocean Division, Hawai‘i. International Archaeological Research Institute, Inc., Honolulu, pp 521–524
Bammann H, Wey H-W (1991) The cultivation of taro in the Palau Islands (Micronesia): a survey of traditional and recent cultivation practices. Palau Community Action Agency, Koror, p 82
Diamond J (2005) Collapse: how societies choose to fail or succeed. Penguin Books, New York
Englberger L, Albert K, Lorens A, Levendusky A (2009) Taro: an important Pohnpei staple food in ethnobotany of Pohnpei: plants, people, & Island culture. University of Hawaii, Honolulu, pp 132–162
Fabricius K (2005) Effects of terrestrial runoff on the ecology of corals and coral reefs: review and synthesis. Mar Pollut Bull 50:125–146
Falanruw MC (1980) Taro growing on Yap, in Research extension series, Hawaii. Institute of Tropical Agriculture and Human Resources. Honolulu, Hawaii, p 105–109
Golbuu Y, Friedlander AM (2011) Spatial and temporal characteristics of grouper spawning aggregations in marine protected areas in Palau, western Micronesia. Estuar Coast Shelf Sci 92:223–231
Golbuu Y, Victor S, Wolanski E, Richmond RH (2003) Trapping of fine sediment in a semi-enclosed bay, Palau, Micronesia. Estuar Coast Shelf Sci 57:941–949
Golbuu Y, Fabricius KE, Victor S, Richmond RH (2008) Gradients in coral reef communities exposed to muddy river discharge in Pohnpei, Micronesia. Estuar, Coast Shelf Sci 76:14–20
Golbuu Y, Wolanski E, Harrison P, Richmond RH, Victor S, Fabricius KE (2011) Effects of land use change on characteristics and dynamics of watershed discharges in Babeldoab, Palau. Micronesia J Mar Biol. doi:10.1155/2011/981273
Kayanne H, Omori M, Fabricius K, Verheij E, Colin P, Golbuu Y, Yukihira H (2007) Coral reefs of Palau. Palau International Coral Reef Center, Koror
Liston J (2009) Cultural chronology of earthworks in Palau, western Micronesia. Archaeol Ocean 44:56–73
Liston J (2011) Archaeological monitoring and emergency data recovery for the Compact Road, Babeldaob island, Republic of Palau. Historic preservation investigations, Phase III. Volume XII: lab analyses, discussion, syntheses. Prepared for the US Army Corps of Engineers, Pacific Ocean Division, Hawai‘i. International Archaeological Research Institute, Inc., Honolulu
Liston J, Tuggle HD (2006) Prehistoric warfare in Palau. In: Arkush E, Allen MW (eds) The archaeology of warfare: prehistories of raiding and conquest. University Press of Florida, Gainesville, pp 148–183
Masse WB, Liston J, Carucci J, Athens JS (2006) Evaluating the effects of climate change on environment, resource depletion, and culture in the Palau Islands between AD 1,200 and 1,600. Quatern Int 151:106–132
McKnight R, Obak A (1960) Taro cultivation in Palau. Anthropological working papers, No. 6, Guam, p 1–47
Palau Society of Historians (2008) Stories with moral lessons. Bureau of Arts and Culture, Ministry of Community and Cultural Affairs, pp 1–60
Richmond RH, Rongo T, Golbuu Y, Victor S, Idechong N, Davis G, Kostka W, Neth L, Hamnett M, Wolanski E (2007) Watersheds and coral reefs: conservation science, policy and implementation. Bioscience 57:598–607
Toy TJ, Foster GR, Renard KG (2002) Soil erosion: processes, prediction, measurement, and control. John Wiley, Technology & Engineering
Victor S, Golbuu Y, Wolanski E, Richmond R (2004) Fine sediment trapping in two mangrove-fringed estuaries exposed to contrasting land-use intensity, Palau, Micronesia. Wetl Ecol Manag 12:277–283
Victor S, Neth N, Golbuu Y, Wolanski E, Richmond RH (2006) Sedimentation in mangroves and coral reefs in a wet tropical island, Pohnpei, Micronesia. Estuar Coast Shelf Sci 66:409–416
Acknowledgments
This study was supported by NOAA Coastal Oceans Program, The Nature Conservancy, The Palau International Coral Reef Center, and The Belau National Museum. The authors wish to thank Arius Merep, Asap Bukurrou, Geory Mereb and Dawnette Olsudong for their assistance during this study as well as the taro field owners Dwight Masami, Rikel Nakamura, and Dirrurcherudel Didil Dengokl Nakamura for allowing the study to be conducted in their taro fields.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Koshiba, S., Besebes, M., Soaladaob, K. et al. Palau’s taro fields and mangroves protect the coral reefs by trapping eroded fine sediment. Wetlands Ecol Manage 21, 157–164 (2013). https://doi.org/10.1007/s11273-013-9288-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11273-013-9288-4