Processes shaping Vietnam's limestone karst biodiversity - the role of barriers and biotic interactions
Final Report Abstract
This project aimed to reveal factors that contributed to the extraordinarily rich biodiversity found in Vietnam. Two major processes, which might be involved in the development and maintenance of this biodiversity, are the restriction of dispersal due to large-scale biogeographical barriers and biotic interactions among taxa at insular habitat patches. One of the most prominent topographical features in northern Vietnam is the Red River valley, which has been proposed to act as a major biogeographical barrier. On a smaller spatial scale, Vietnam’s biodiversity might have been shaped by interspecific competition among taxa, which inhabit the country’s calcareous limestone karst areas. In order to study these two processes, I focused on material from the collections of the Natural History Museum in London (NHM). The NHM harbours one of the world’s largest collections of Vietnamese land snails. For examining the role of the Red River valley as a barrier for dispersal, I used Clausiliidae (door snails) as a model group. I compared the faunal composition of Clausiliidae on both sides of the Red River based on the NHM collections as well as on records from the literature and other museum collections. My results revealed that the Red River valley separates two considerably different Clausiliidae faunas and thus acts as or coincides with a major biogeographical barrier for these land snails. To examine the role of biotic interactions among taxa at insular limestone karst areas, I had to change my model taxon to the land snail genus Cyclophorus as it turned out during my work on the collections that the number of Clausillidae species in my key study areas was not sufficient for tackling this question. I used a combination of molecular phylogenetics and morphometrics in order to detect non-random distribution patterns of Cyclophorus spp. among karst areas in northern Vietnam. I could show that for most karst areas, lineages were more distantly related and less morphologically similar than expected under a scenario of a random distribution. This pattern suggests that competition among different lineages has shaped these communities. During my research project, I could detect processes that have shaped the land snail biodiversity in Vietnam’s karst landscapes on different spatial scales. Furthermore, my findings increased the knowledge about patterns of karst biodiversity in general.
Publications
- (2016): Community assembly among limestone karst areas – Insights from Vietnamese land snails. Molluscan Forum, London, 14
Oheimb, P.V. von; Oheimb, K.C.M. von; Ablett, J. & Naggs, F.
- (2016): Diversity and distribution of door snails around the Red River in Vietnam. World Congress of Malacology, Penang, 251
Oheimb, P.V. von; Oheimb, K.C.M. von; Ablett, J. & Naggs, F.
