AsianScientist (Feb. 16, 2021) – Scientists surveying wildlife in the Philippines have rediscovered a rare mouse thought to have perished during the cataclysmic 1991 explosion of Mt. Pinatubo. Their findings were published in the Philippine Journal of Science.
In June 1991, Mt. Pinatubo erupted in one of the most violent volcanic eruptions of the 20th century. Spewing thick layers of lava and ash onto the surroundings, the explosion’s impact was worsened by the typhoons and monsoon rains that soon came after.
Lethal landslides sent a concrete-like mixture of volcanic material, debris and water called lahar down the mountainside, with the wet, heavy ash killing over 800 people. The lush forests that once covered Pinatubo were also destroyed—along with the fauna that lived within these forests.
Or so scientists thought. After all, there had been no surveys of animals—mammals, in particular—on Mt. Pinatubo before. However, specimens housed in the US’ National Museum of Natural History gave some historical context. A preserved specimen of a small rodent proved to be especially intriguing, and was eventually described as a new species in 1962 called the Apomys sacobianus or the Pinatubo volcano mouse.
Seeking to discover the fate of the tiny mammal, late Field Museum researcher Mr. Danilo “Danny” Balete and his team returned to Mt. Pinatubo in 2011. Even after twenty years, the harsh landscape still bore marks of the fateful eruption. Instead of old-growth forests, the team found a sparse mix of grass, shrubs, low-growing vines and trees populated the area—all characteristic of early-stage second-growth habitats.
To their surprise, the researchers also documented a total of 17 species living on the mountain, including bats, rodents and large mammals like wild pig and deer. Far from being wiped out by the eruption, the team found that the most abundant species was the Pinatubo volcano mouse.
Their discovery ran contrary to the team’s initial hypothesis. Elsewhere in the Philippines, field surveys of small, non-flying mammals revealed that old-growth forests contain more native species compared to non-native or ‘pest’ species. Meanwhile, in heavily disturbed second-growth habitats—especially those near croplands—non-native mammals were most abundant.
Despite the fact that all surveyed areas in the mountain had scrubby, second-growth vegetation rather than forest, native rodents were found everywhere. Their findings prove that small native mammals are far resilient than their size suggests and have a high tolerance for disturbances like volcanic eruptions. As Mt. Pinatubo continues to recovers from the eruption’s damage, the forests will return and other mammalian species will move in.
“Mt. Pinatubo could be a wonderful place to establish a long-term project to monitor habitat recovery and community re-assembly following the eruption,” said co-author Dr. Eric Rickart of the Natural History Museum of Utah, who completed the study after Balete’s sudden death in 2017. “Such information would be helpful in efforts to regenerate the many areas that have been deforested by people.”
“Knowing that a species once thought to be vulnerable, even feared to be extinct, is actually thriving is the finest tribute to Danny that we can imagine,” added co-author Dr. Lawrence Heaney of the Field Museum.
Source: Field Museum; Photo: Danny Balete/Field Museum.
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