Extended Data Figure 2: Geologic age and area of the four main geologic complexes of the Hawaiian Islands exemplifying the rate of area decrease with time due to subsidence and erosion for volcanic islands.
From: Late Quaternary climate change shapes island biodiversity
In this example scenario, we assume that the four major complexes of the Hawaiian Islands (Fig. 2b) all reached approximately the same maximum area size and that the youngest complex, Big Island, already reached its full extent. The area decrease from Big Island to Maui Nui equals −0.0072 km2 per year and from Maui Nui to O’ahu −0.0016 km2 per year (see map in Fig. 2b). The linear fit over all points has a slope of −0.0016 km2 per year. The negative exponential curve has a slope of −0.0034 km2 per year at the beginning and of −0.0006 km2 per year at the end. For comparison, the 184 islands used for this paper experienced an area decrease due to rising sea levels of 0.5035 km2 per year over 10,000 years on average and the post-LGM decrease in island area for islands like Anegada or Mahé, was up to 1,000 times faster than the area decrease indicated here for the Hawaiian Islands. The notion that post-LGM changes have been much faster than average rates of geologic processes of island formation and erosion, therefore, most likely holds true even if the assumptions above are not perfectly met.
