Some of the most prominent biodiversity hotspots in the world are located in mountains, but so far attempts to explain these hotspots from current local environmental factors has failed. We direct the attention to potential external drivers, notably to persistent impacts from oceanic currents.
Marine impacts on coastal mountain hotspots
Many areas with an unexplained high diversity of endemic species are found on escarpments and mountain ranges near tropical coasts. With a focus on these hotspots, we examine variation in marine impacts on coastal mountains, develop palaeomaps for marine current systems and analyze the relationship between changes in palaeocurrents and geographical patterns of diversification in terrestrial biota.
The main research questions are:
- Can the climatic impact from stable oceanic currents explain the existence of terrestrial biodiversity hotspots?
- Can the biodiversity hotspots in mountain regions near warm tropical coasts act as dispersal centers?
- How can we explain the (few) biodiversity hotspots that are located deep inside the continents?
- What is the relative roles of speciation and persistence of lineages in the diversification process in biodiversity hotspots?
So far, some biodiversity hotspots in tropical montane regions have been explained in an ad hoc way from climatic impacts from tropical oceans creating persistent cloud forest conditions. We now use global distributional databases for terrestrial vertebrates, current environmental data and modeled variation in marine circulation systems to determine which factors that best explain the great variation in biodiversity among montane regions.
Katherine Richardson, Mohamed Adjou, Zhiheng Wang, Jørgen Bendtsen, Carsten Rahbek
The biodiversity hotspot of the Eastern Arc Mountains of Tanzania has been explained from climatic stability related to the circulation system of the Indian Ocea. Through studies of tectonic changes and sediment data from drill-cores, the project aims to determine the time window for this climatic impact, and to link geochronology with variation in speciation-per-time along elevational gradients in the mountains.
Jon Fjeldså, Nikolaj Scharff
Rauri Bowie, University of California (Berkeley)
Using palaeomodels for oceanic flows, this project aims to demonstrate to what extent changes in the global circulation systems are reflected in the geographical patterns of diversification in terrestrial environments. For this we use models of evolution of passerine birds (see Biogeography and Phylogenies theme) as well as distributions of old (relictual) species.
Jørgen Bendtsen, Katherine Richardson
Mohamed Adjou, Jon Fjeldså, Zhiheng Wang