Island Conifers Face Extinction Threat From Climate Change

(CN) – Despite being able to survive in harsh climate conditions, researchers say in a study released Monday that several species of conifer trees and shrubs native to small islands could face extinction by 2070.

The study, published in the journal Nature Climate Change by scientists at Brown University, found that up to 25% of 55 conifer species on small islands around the world could be extinct within five decades, including pine and fir trees.

Researchers found species native to smaller islands to be most at risk, specifically those found on islands less than 12,427 square miles.

“Our work shows that species native to relatively small islands are in a lot of danger from climate change, and relatively soon,” said Dov Sax, study co-author and deputy director of the Institute at Brown for Environment and Society. “But the work also helps us to identify which species are most at risk and which are least at risk, which helps to prioritize conservation.”

Rather than use the traditional method of assessing extinction risk, researchers said they realistically accounted for the conifers’ ability to survive various climate conditions.

“If you just look at conditions in native ranges and you model risk off of that, you’d conclude that everything on small islands is doomed,” Sax said. “But we know that many of these species have survived past instances of climate change, so what we wanted to do here was think about what conditions species could potentially thrive in if they needed to.”

Scientists were able to determine a more realistic extinction threat using data on conifers that are known to live outside of their native climate conditions, constructing three categories of “climate niches.”

“First is the realized niche, which consists of the climate conditions in a species’ native range,” the study said. “Second is the fundamental niche, which includes conditions outside those within a species’ native range in which plants can reproduce well enough to sustain a population on their own. Third is the tolerance niche – the conditions in which individual plants can survive, but are not able to reproduce at a rate that sustains a population. In other words, species pushed to the tolerance niche are on the road to extinction.”

Once the niche categories were established, scientists used Intergovernmental Panel on Climate Change predictions for future global warming to find which species faced the danger of extinction. The study determined that 23.6% of the species would be outside of their fundamental niches.

“At first, we were encouraged to discover that most species show a lot of wiggle room in their climatic niches,” said Kyle Rosenblad, a study co-author. “But alarmingly, all this wiggle room still isn’t enough to buffer some of them from predicted changes in climate.”

While some species of conifers, like the Canary Island Pine, are expected to survive climate changes, others such as the Bermuda Cedar, will face extinction by 2070.

“We found a whole range of range of species that will look like they’re fine,” Sax said. “They’ll be alive and you may even see some seedlings. But since they can’t reproduce sufficiently to maintain their population on their own, they’ll actually be on the road to extinction.”

Sax said that he hopes identifying conifers most at risk for extinction can spur action into ensuring that they and other plant life survive in the future.

“If you protect areas that are good for these conifers, you protect areas that are good for other plant species as well,” Sax said.

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