3:30PM - 4:20PM
Jason R. Ali Department of Earth Sciences, HKU
Volcanic ocean islands (e.g. those in the Galápagos, Lesser Antilles and Cape Verde archipelagoes) and their hosted biological assemblages are viewed by many biologists as being idealized natural laboratories/systems. As a consequence they receive huge amounts of attention. However, soon-to-be-published research carried out by the speaker and his colleague, Shai Meiri (Tel Aviv University, Israel), indicates that a highly influential theoretical model accounting for the growth of biodiversity on the volcanic ocean islands is fundamentally flawed. The assumption that individual landmasses operate as “species factories” does not stack up, at least not for the reptiles as well as the other groups of terrestrial vertebrates (amphibians, mammals). Instead, the build-up of biodiversity in such settings results almost exclusively from immigration. There is, though, an extra twist in that there appears to be two very different assemblage types, the control being the ease, or otherwise, by which the islands can be colonized by land-locked animals that wash-in from continental source areas on uprooted trees/vegetation mats etc. The presentation will explain the new findings.