Fourteen new species of shrew have been discovered during a decade-long survey of small mammals on the Indonesian island of Sulawesi.
Shrews are a diverse group of small mammals that can be found almost anywhere in the world. Despite their global distribution, not a lot has been documented about shrews that dwell in the world’s mountainous, tropical regions.
To investigate these animals on Sulawesi, Jake Esselstyn at Louisiana State University and his colleagues began setting several pitfall traps across the island in 2010, including on dozens of mountains at different elevations.
Over 10 years, they trapped and examined 1368 individual shrews spread evenly across the island. Analysis of their physical features and DNA revealed that the team had found 21 species of shrew, and they all live exclusively on Sulawesi. Of the 21 species, 14 were previously unknown. These discoveries make Sulawesi the host of three times more shrew species than any other island in the world. This may be because the island fosters remarkable biodiversity, or it could be that shrews on other islands are poorly documented, he says.
The researchers suspect that Sulawesi’s geography may be a reason for such diversity in the shrews. It is uniquely shaped: its four peninsulas form a K-like shape and are also quite mountainous, with six peaks reaching at least 3000 metres tall.
The peninsulas may promote isolation between populations, and the high mountains create strong climatic gradients that could lead to big differences in the vegetation. It is possible that shrews diversified in response to the geography, though this idea is yet to be tested, says Esselstyn.
There may be even more shrew species on Sulawesi that haven’t been found yet. The animals in this study were collected at sites up to a height of 2700 metres, so it wouldn’t be surprising if there were shrew species at even higher altitudes, says Esselstyn.
“We hope that our findings can encourage more work and funding to study biodiversity on mountains,” says co-author Heru Handika, also at Louisiana State University. “With the rapidly growing economy of Indonesia and the growing population, deforestation on mountains would increase in the near future. Many of those species would be gone before we know they exist.”
“We really need to have a good assessment of life on the planet. We need to know how many species there are and where they live,” says Esselstyn. “If we don’t know these things, then we stand little chance of having true insight into how that life evolved, how that life is maintained now and how to conserve it.”
Journal reference: Bulletin of the American Museum of Natural History, DOI: 10.1206/0003-0090.454.1.1
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