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Sea-level rise ( SLR) from global warming may have severe consequences for biodiversity; however, a baseline, broad-scale assessment of the potential consequences of SLR for island biodiversity is lacking. Here, we quantify area loss for over 12 900 islands and over 3000 terrestrial vertebrates in the Pacific and Southeast Asia under three different SLR scenarios (1 m, 3 m and 6 m). We used very fine-grained elevation information, which offered >100 times greater spatial detail than previous analyses and allowed us to evaluate thousands of hitherto not assessed small islands. Depending on the SLR scenario, we estimate that 15-62% of islands in our study region will be completely inundated and 19-24% will lose 50-99% of their area. Overall, we project that between 1% and 9% of the total island area in our study region may be lost. We find that Pacific species are 2-3 times more vulnerable than those in the Indomalayan or Australasian region and risk losing 4-22% of range area (1-6 m SLR). Species already listed as threatened by IUCN are particularly vulnerable compared with non-threatened species. Under a simple area loss-species loss proportionality assumption, we estimate that 37 island group endemic species in this region risk complete inundation of their current global distribution in the 1 m SLR scenario that is widely anticipated for this century (and 118 species under 3 m SLR). Our analysis provides a first, broad-scale estimate of the potential consequences of SLR for island biodiversity and our findings confirm that islands are extremely vulnerable to sea-level rise even within this century. [ABSTRACT FROM AUTHOR]

Sea-level rise ( SLR) due to global warming will result in the loss of many coastal areas. The direct or primary effects due to inundation and erosion from SLR are currently being assessed; however, the indirect or secondary ecological effects, such as changes caused by the displacement of human populations, have not been previously evaluated. We examined the potential ecological consequences of future SLR on >1,200 islands in the Southeast Asian and the Pacific region. Using three SLR scenarios (1, 3, and 6 m elevation, where 1 m approximates most predictions by the end of this century), we assessed the consequences of primary and secondary SLR effects from human displacement on habitat availability and distributions of selected mammal species. We estimate that between 3-32% of the coastal zone of these islands could be lost from primary effects, and consequently 8-52 million people would become SLR refugees. Assuming that inundated urban and intensive agricultural areas will be relocated with an equal area of habitat loss in the hinterland, we project that secondary SLR effects can lead to an equal or even higher percent range loss than primary effects for at least 10-18% of the sample mammals in a moderate range loss scenario and for 22-46% in a maximum range loss scenario. In addition, we found some species to be more vulnerable to secondary than primary effects. Finally, we found high spatial variation in vulnerability: species on islands in Oceania are more vulnerable to primary SLR effects, whereas species on islands in Indo-Malaysia, with potentially 7-48 million SLR refugees, are more vulnerable to secondary effects. Our findings show that primary and secondary SLR effects can have enormous consequences for human inhabitants and island biodiversity, and that both need to be incorporated into ecological risk assessment, conservation, and regional planning. [ABSTRACT FROM AUTHOR]