Nowhere to Go
Most animals— and especially most birds— are fairly mobile. As temperatures increase in response to global climate change, they can theoretically shift their ranges toward cooler regions. The reality is complicated, however. From cities and agriculture to rivers and mountain ranges, barriers often stand in the way.
Mountainous species face a different sort of barrier. Rather than moving toward the poles to find cooler temperatures, mountaindwelling species are shifting their ranges toward higher elevations in response to climate change. But mountains only stand so tall. And when a species reaches that limit, they may be stranded with nowhere else to go. Recent studies suggest this will be the case for several songbirds in New Guinea— already they have shifted their ranges upslope by more than 400 feet in the past 50 years. Some populations are already restricted to the very peak of the mountain where they live. Scientists predict that several of these mountainrestricted populations will have disappeared entirely by the end of this century. This potential fate is especially concerning for endemic species— those found in only one place or region— such as the Critically Endangered Cerulean Flycatcher, which is already restricted to the upper elevation of an extinct Indonesian volcano known as Mt. Sahendaruman.
Cerulean Flycatcher | Agami Photo Agency
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Sensitive to Change
Tropical montane forests are among the most biodiverse in the world, harboring many species of plants and animals found nowhere else. Among these are tree-dwelling orchids and other plants— known as epiphytes— that grow on tree branches or trunks rather than rooted in the ground.
These tree-dwelling plants tend to have relatively small natural ranges, and scientists have long feared this would make the plant group especially vulnerable to climate change. One recent study confirms those fears. Over a three-year period, a team of researchers transplanted a variety of these plants to new sites at slightly higher or lower elevations and then monitored the plants’ health and survival. Based on these results, climate change could cause the extinction of one-third or more of all epiphyte species— including orchids, ferns, and bromeliads— by the end of this century.
Platystele crinita orchid | Fundación Ecominga