Pohnpei, Federated States of Micronesia Mangrove Elevation Survey Data

Publication Date

2021-02-11

Start Date

2017-02-15

End Date

2019-04-25

Irwin, J.R., Gesch, D.B., Buffington, K.J., and Danielson, J.J., 2021, Pohnpei, Federated States of Micronesia Mangrove Elevation Survey Data: U.S. Geological Survey data release, https://doi.org/10.5066/P9DDZX32.

Type: Related Primary Publication

The Federated States of Micronesia (FSM), a Pacific island nation, is home to fifteen different species of mangrove trees, as well as one hybrid species. Mangroves occur on approximately 16% of the land area of the high relief volcanic island of Pohnpei, FSM. Mangroves are intertidal tree species that provide many ecosystem goods and services. These ecosystem goods and services include serving as sources of timber and fuelwood, providing habitat for fisheries, filtering coastal waters, sequestering carbon, and providing protection from storms and storm surge. Each mangrove species has a range of tidal conditions which it can tolerate, with variation in the magnitude of the range for each species. Microtopography determines the length of time mangroves are exposed to air and tidal inundation, thus controlling the distribution of mangrove species. Sea-level rise is a threat to mangroves because of the fixed range and frequency of inundation that each species can tolerate, and the Pacific islands occur in an area that is the most impacted by rising sea levels. However, with proper management strategies, it may be possible to mitigate some of the impacts of rising sea levels by conserving appropriate areas for inland mangrove migration and other adaptation strategies. The data collected during these field efforts will be used to assess the elevation ranges of the mangroves of Pohnpei and in models that project future sea level rise on the island of Pohnpei. A mangrove vulnerability assessment for Pohnpei can be conducted following the elevation range assessment and sea-level rise modeling, which would provide a basis for management planning for adaptation and conservation. Survey grade data collection in the mangrove forests of Pohnpei is difficult. Dense canopy inhibits survey grade GNSS signals. Locations outside of the mangroves, often on coral islands, had to be found in order to set up the GNSS base station. Additionally, clear sky areas had to be located in order to establish control for the total station and level. Setting up a tripod in mangrove roots is problematic. Furthermore, mangrove roots limit site lines and are tricky to walk upon and over. Tides also had to be worked around during the field campaigns. High tides were necessary to travel to and from the sites in most instances, but high tides also slowed work by forcing the team to trudge through waist level or higher water on the way to and from sites and sometime during data collection efforts. These challenging conditions limited the amount of data that could be collected during the field campaigns and also necessitated local support. The USGS would like to thank Bejay Obispo, Angel Jonathan, Kirino Olpet, Yakob, and McKay from the Conservation Society of Pohnpei (CSP) and Yosda Sailas, Eugene Eperiam, Emos Eperiam, and Bersin Elias from the Pohnpei Department of Forestry for their assistance with the fieldwork. The USGS would also like to thank Tamara Greenstone-Alefaio from the Micronesia Conservation Trust and Francisca Sohl Obispo from CSP for their logistical and planning support.

• National and Regional Climate Adaptation Science Centers
• Pacific Islands CASC
• USGS Data Release Products