Evolution of mountain endemism

Tropical mountains are hot spots of biodiversity and endemism but the evolutionary origins of their unique biotas are poorly understood. In varying degrees, local and regional extinction, long-distance colonization, and local recruitment may all contribute to the exceptional character of these communities. Also, it is debated whether mountain endemics mostly originate from local lowland taxa, or from lineages that reach the mountain by long-range dispersal from cool localities elsewhere. 

In order to answer these questions a Dutch-Malaysian scientific expedition collected tens of thousands of plants, animals and mushrooms at 37 locations on and around Mount Kinabalu in Sabah, Malaysian Borneo. The group used DNA Barcodes that in many cases were augmented with one or more other phylogenetically informative loci. 

The researchers showed that most of the species that occur on the mountain are younger than the mountain itself (6 Million years). They also demonstrated that the endemic biodiversity consists of two groups. Some of the unique species are immigrants from far away areas such as the Himalayas or China, most of which already adapted to a cool environment. Other endemic species evolved from local species that initially occurred at the foot of the mountain and gradually adapted to the cooler conditions in higher altitudes.

It is sometimes thought that tropical mountains are also locations where very old species survive. However, our research reveals that most of the species are young. New species evolve at the top the mountain, but these often evolve from species that already lived under such conditions. This is important for the protection of the endemic species. Our research reveals the extent to which species are able to evolve to keep up with climate change and this allows us to make predictions for the future.