Reef island dynamics and mechanisms of change in Huvadhoo Atoll, Republic of Maldives, Indian Ocean

Planform changes in 184 reef islands in Huvadhoo atoll, Republic of Maldives are quantified in the context of global environmental change and anthropogenic impacts. Aggregated at the atoll scale, results show that, over the past four decades, total land area increased by 59 ha (2.4%). Land reclamation of 93.8 ha on 12 inhabited islands was the dominant factor in the increase in land area. Excluding reclaimed islands from the dataset reveals net erosion of atoll island area of 28.5 ha (1.5%). Erosion was prevalent on 45% of islands with remaining islands being stable (40%) or increasing in area (15%). A relationship between island size and planform change was identified. Small islands (<10 ha) were dominated by erosional responses whereas larger islands were dominated be accretion. Results indicate future transformation in atoll land resources to fewer smaller islands but an increase in size of larger islands. Results also indicate that all islands changed, underscoring the dynamic nature of islands on reef surfaces. Ten distinct styles of island adjustment were identified from the dataset. Direct human impact, through reclamation, was found to have a more significant impact on island change in the atoll than secondary factors such as sea level change and changes in reefal sediment supply. Implications for the Maldives are discussed and indicate that land resources for ongoing habitation will persist across the next century though the location of tourism activities on smaller islands places this valuable economic sector at risk. Analysis of historic island change provides a rich information source to reconsider landuse planning in the context of climate change adaptation.