Nav: Home

World's island conifers threatened with extinction from climate change

July 15, 2019

PROVIDENCE, R.I. [Brown University] -- A new study finds that climate change will put many conifer species native to small islands around the world on the road to extinction by 2070, even after allowing for some realistic wiggle room in the range of climate conditions those species might be able to withstand.

The study, led by researchers from Brown University, found that up to a quarter of the 55 conifer species (a group that includes fir and pine trees) included in the study will face extinction based on Intergovernmental Panel on Climate Change (IPCC) predictions for future global warming. Species most at risk tend to be those native to smaller islands, the study found, with extinction risk increasing rapidly on islands smaller than 20,000 square kilometers.

"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, deputy director of the Institute at Brown for Environment and Society and a study coauthor. "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."

The research, published in Nature Climate Change, takes an emerging approach to studying extinction risk. Researchers have traditionally assessed risk by looking at the range of climate conditions in a species' native range and assuming that those are the climate limits the species can withstand. But for this new study, the researchers hoped to use a potentially more realistic estimate of the climate conditions that species can handle.

"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," said Sax, who is a professor of ecology and evolutionary biology at Brown. "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."

To do that, the researchers used data on where members of a given species are known to survive and thrive outside their native ranges. Conifers are a popular for planting in lawns and gardens, which means there are plenty of documented instances of individual trees and populations living away from their native islands in a variety of climates.

Data on where these species are known to live enabled the researchers to construct three categories of climate niches for the species in the study. First is the realized niche, which consists of the climate conditions in a species' native range. 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. The researchers determined that by looking for instances where species, likely first planted horticulturally, were able to leak out into the wild and establish breeding populations. 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.

Having established niche categories for each species, the researchers then used IPCC estimates of future climate change to see which were in extinction danger. The study found that 23.6 percent of species in the study will be outside their fundamental niches under the IPCC's most extreme climate scenario, which Sax points out is also the most likely scenario given our current carbon emission levels. Some species, the analysis showed, will be outside even their tolerances niches. Importantly, Sax says, estimates of expanded niches helps to give an idea which specific species are at risk and which are not, which could be important for conservation.

"At first, we were encouraged to discover that most species show a lot of wiggle room in their climatic niches," said Kyle Rosenblad, a research in Sax's lab and a study coauthor. "But alarmingly, all this wiggle room still isn't enough to buffer some of them from predicted changes in climate."

The study showed that the Canary Island Pine, for example, is expected to stay within its fundamental niche -- the climate conditions where it is found to reproduce on its own outside its native range -- suggesting that it is potentially safe from extinction. On the other end of the spectrum is the Bermuda Cedar, which is expected to be pushed out of not only its fundamental niche, but even its tolerance niche. That means that there will be no place on its native island of Bermuda where individuals from this species could survive.

A third category includes species like the Norfolk Island Pine, which is native to the small island of Norfolk in the South Pacific. Future climate conditions in Norfolk are expected to be outside the species' fundamental niche, but within its tolerance niche. That means individuals will still be able to survive in some places, but they won't be able to reproduce without human assistance. That makes extinction inevitable without human intervention.

"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."

By identifying the species most at risk for extinction, Sax says, the study may help to direct efforts to save them through engineering solutions, such as irrigation or other strategies. And by identifying the species with a good chance of surviving, the study could help to concentrate conservation efforts toward preserving their habitats. That would be of benefit of not only conifers, but other plant species more broadly.

"If you protect areas that are good for these conifers, you protect areas that are good for other plant species as well," Sax said.
-end-


Brown University

Related Climate Change Articles:

The black forest and climate change
Silver and Douglas firs could replace Norway spruce in the long run due to their greater resistance to droughts.
For some US counties, climate change will be particularly costly
A highly granular assessment of the impacts of climate change on the US economy suggests that each 1°Celsius increase in temperature will cost 1.2 percent of the country's gross domestic product, on average.
Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Climate change scientists should think more about sex
Climate change can have a different impact on male and female fish, shellfish and other marine animals, with widespread implications for the future of marine life and the production of seafood.
Climate change prompts Alaska fish to change breeding behavior
A new University of Washington study finds that one of Alaska's most abundant freshwater fish species is altering its breeding patterns in response to climate change, which could impact the ecology of northern lakes that already acutely feel the effects of a changing climate.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
The psychology behind climate change denial
In a new thesis in psychology, Kirsti Jylhä at Uppsala University has studied the psychology behind climate change denial.

Related Climate Change Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#532 A Class Conversation
This week we take a look at the sociology of class. What factors create and impact class? How do we try and study it? How does class play out differently in different countries like the US and the UK? How does it impact the political system? We talk with Daniel Laurison, Assistant Professor of Sociology at Swarthmore College and coauthor of the book "The Class Ceiling: Why it Pays to be Privileged", about class and its impacts on people and our systems.