Most of the unique species of flora, fauna and fungi found on Mount Kinabalu in Sabah, Malaysian Borneo, are younger than the mountain itself in evolutionary terms. Some have evolved from immigrant ancestors and others from local ones. These findings are important for predicting the chance of extinction in endemic species as a result of, for example, climate change. These conclusions, drawn by 55 scientists from 23 institutes including Wageningen UR, appeared online in Nature on 12 August.
Tropical mountains show an extremely high biodiversity, the reason being that the temperature, and thus the environment, changes rapidly with increasing altitude. That is why some species – the endemic species – occur only at the top of mountains. Mount Kinabalu (Malay: Gunung Kinabalu) in Sabah, Malaysian Borneo is a good example of this. The 4095-metre-high mountain, a UNESCO World Heritage site, is home to hundreds of unique species of plants and animals.
The evolutionary origin of the unique flora and fauna of tropical mountains is not, however, well understood. That is why a scientific expedition was organised in 2012 by Naturalis Biodiversity Center and Sabah Parks. Researchers from Wageningen UR, Naturalis and various other institutes collected dozens of endemic species on Mount Kinabalu during the expedition. DNA techniques were used to determine the species from which the endemic ones have evolved. The analytical data from 1800 samples formed the basis of the publication in Nature.
The researchers have demonstrated that most of the species occurring on this 6-million-year-old mountain are younger than the mountain itself. They also showed that the endemic biodiversity consisted of two groups. Some of the unique species are immigrants from faraway areas such as the Himalayas or China where they were already adapted to a cooler environment, while the other endemic species evolved from local species at the foot of the mountain; these have gradually adapted to colder conditions.
Over a period of two weeks in 2012, the researchers collected tens of thousands of plants, animals and toadstools from 37 locations in and around Kinabalu. There were ferns, mosses, orchids, snails, worms, insects, spiders, frogs, and so on. The results of this research demonstrate that the mountain is a hotbed of evolution. “It used to be thought that tropical mountains were places where really old species could survive, but our research has shown that most of the species are young,” Menno Schilthuizen from Naturalis says. New species develop at the top of a mountain, but have often evolved from species which were already living in such circumstances. He goes on to explain: “This is important for protecting endemic species. Now you can see to what extent species are able to evolve along with climate change and this allows us to make predictions for the future.”
Wageningen UR researchers Lisa Becking (Marine Animal Ecology, IMARES) and René Geurts (Laboratory of Molecular Biology, Wageningen University) took part in this project. Becking was one of the expedition organisers and coordinated the sampling for DNA barcoding. She was also one of the core team that wrote the publication. Geurts collected species from the genus Parasponia and the genus Trema in order to better understand the relationship between Parasponia trees and the soil bacterium Rhizobium.
Becking was asked because she had previously organised expeditions to Indonesia for scientific fieldwork in marine environments. “I’m interested in the spreading patterns of species and the processes which play a role in creating biodiversity. The questions and analyses are the same, but sampling in ancient forests is completely different to doing it on coral reefs!” This project is particularly interesting, Becking believes, because it involves looking at the evolutionary history of a large number of organisms and not just one taxon. “This allows us to analyse general processes which apply to the whole community.”
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The project was financed by FES funding, the Netherlands Organisation for Scientific Research (NWO), the Alberta Mennega Foundation, the Ecology Fund of the Royal Netherlands Academy of Arts and Sciences (KNAW), the Uyttenboogaart-Eliasen Foundation and Pro Acarologia Basiliensis.
‘Evolution of endemism on a young tropical mountain’ by Merckx VSFT, Hendriks K, Beentjes K, Mennes C, Becking LE et al., Nature, 12 augustus 2015