Seashore in the mountain: limestone-associated land snail fauna on the oceanic Hahajima Island (Ogasawara Islands, Western Pacific)

Land snails on oceanic islands, derived from mainland seashore ancestors, retain ecological preferences for high-pH, calcium-rich microhabitats with sparse vegetation cover. A study on Hahajima Island (Ogasawara Islands) found that these seashore-derived species exhibit higher diversity on limestone outcrops than non-limestone areas, while other snail species show no such preference. Additionally, seashore-derived species dominate limestone ridges over doline soils, even within limestone regions. This suggests their habitat use remains constrained by ancestral ecology, limiting colonization to exposed, calcium-rich environments. Notably, some seashore-derived species include cave-dwelling forms lacking functional eyes, indicating that only these lineages can colonize caves due to their ecological traits. The findings highlight how ancestral habitat preferences can persist and shape descendant species' ability to exploit novel habitats, even in depauperate island ecosystems.

WADA, S., & CHIBA, S. (2011). Seashore in the mountain: limestone-associated land snail fauna on the oceanic Hahajima Island (Ogasawara Islands, Western Pacific). Biological Journal of the Linnean Society, 102(3), 686–693. https://doi.org/10.1111/j.1095-8312.2010.01604.x