Highest concentration of unique mammals found in Luzon —study

There's great diversity even for landlocked flightless creatures on an island, a new study suggests.

In a paper titled by "Doubling diversity: a cautionary tale of previously unsuspected mammalian diversity on a tropical oceanic island" published in the scientific journal Frontiers of Biogeography, Luzon is revealed to have the greatest concentration of unique mammals.

Out of the 56 species of non-flying mammals living on the island, 52 are endemic in the area and found nowhere else in the world. About half of those species were discovered during the 15-year study led by Lawrence R. Heaney, Negaunee Curator of Mammals at The Field Museum in Chicago.

Heaney and his team from the University of the Philippines, University of Minnesota, and Florida State University sought to test "the assumption that mammalian diversity in tropical oceanic islands is well documented" and, with the 28 new species they discovered in the course of their research, this assumption proved to be false.

According to their study, large islands accelerate evolution. Outside the thinking that "only the fittest survive," isolated species also thrive when there are no predators or competitors.

A spacious island like Luzon, which is about 40,000 square miles, allowed for different species to flourish—especially because of the pockets of unique habitats provided by the various mountains found in it.

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The mountains provide "sky islands" where species adapt to specific environments and adaptation is a key ingredient in diversity.

"The animals are isolated high on the scattered mountains, so they inevitably diverge. Given enough time, you begin to see huge biodiversity," Heaney said in an interview with The Field Museum. "In the process of trying to understand how that happens, we doubled the number of known species on Luzon."

Danny Balete, a research associate at the Field Museum and co-author of the paper, said that learning about conservation is the next step.

"The Philippines is one of the most heavily deforested countries in the tropics; only about seven percent of the old-growth tropical forest is left. We learned that quite a few of the species are seriously threatened by habitat loss and over-hunting, but none are yet extinct," Balete said.

He added, "Protecting all of these species from extinction is going to be a big challenge. The good news is that when the native forest is allowed to regenerate, the native mammals move back in, and the pest rats get kicked out."

Their study notes that their results are not unique to the Philippines, with more species waiting to be discovered in Luzon and other large tropical oceanic islands like Sulawasi, Indonesia.

The new species cited in the studies are mostly mice and they wrote that "some additional may yet be discovered. Heaney said that knowing what thrives in an environment will lead to more effective methods of conservation. —ALG, GMA News