Search

We used publicly available land-cover datasets (1921, 1947, 1976, 1992, 2001, 2006, 2014) to assess land-cover change on Babeldaob Island, Republic of Palau. Land-cover data were organized, classified, and summarized by area and percentage of island cover for forest, mangrove, non-forest vegetation, and non-vegetation. Japanese colonial administration of the island between 1921 and 1947 included industrial mining and agriculture, which reduced total non-mangrove forest cover by 16%. Temporal vegetation cover dynamics from 1947 through 2014 indicate unassisted forest regeneration of 12% with a concomitant decrease in non-forest vegetation including abandoned agriculture, the majority of which happened by 1976. Mangrove cover appears to have remained stable throughout the 93 year study period. Ground-truth observations showed the highest rates of vegetation cover change since 1976 for non-vegetated areas, followed by marsh and swamp forest. The proportion of non-vegetated cover increased at least twofold after WWII, with at least half comprising roads. Contrary to other tropical geographies, we saw forest expansion following completion of a major perimeter road. However, the larger landscape is permeated by dynamic forest edges subject to wildfire and other land-use disturbances. [ABSTRACT FROM AUTHOR]

Coastal flooding occurring in Oceania is often attributed directly to Climate Change-induced sea level rise. This overlooks how post-World War II urbanization, intranational migrations to urban centers, expanded development next to coastlines increasing risk to coastal flooding. This research seeks to determine how urbanization contributes to coastal flooding in the Pacific and show different ways those nations can adapt to future sea level rise.Tracking urbanization in Pacific Islands is difficult because few maps of pre-urbanized conditions are available. Using the Republic of Palau as a case study, maps created by the Japanese government before World War II and by the US after World War II were digitized through GIS and compiled with recent data collected by Palau to track urbanization. This was compared with tide gauge data to quantify the risk of coastal flooding due to urbanization and separately, sea level rise. Additionally, the actual impact on households living next to the coast was investigated through questionnaire surveys collected in the urban center. Spatial data illustrated clear expansion towards the coastline while tide gauge data revealed a 3mm increase in average high tides per year. The difference between buildings at risk from present and previous sea levels was less than 1%. Questionnaire surveys showed that of households bordering the coastline, Palauans from the urban center experienced 6% less flooding than Palauans who migrated after the war. These findings suggest that population growth in the urban center likely increased the exposure to chronic coastal flooding. Action is even more necessary as future sea level rise magnifies the risk of coastal flooding. This relationship highlights the diversity of potential pathways for Pacific nations to minimize their exposure to hazards exasperated by Climate Change. Keywords: urbanization, climate change, coastal flooding, Pacific Islands [ABSTRACT FROM AUTHOR]