The frequency of local species extinctions related to climate change across different climatic regions, habitats, and gradients. (A) Species are categorized as temperate or tropical (based on the location of the study), and the percentage of species with one or more local extinctions is shown, along with the sample sizes of species in each region. (B) Species are categorized as terrestrial, freshwater, or marine, and the frequency of species with local extinctions is shown (along with total species per habitat). (C) Species are categorized based on whether they were surveyed along elevational or latitudinal transects. Vertical lines indicate 95% confidence intervals on the estimated frequency of species with local extinctions. Graphic: John J. Wiens, 2016 / PLOS

By Sean Greene
13 December 2016 (The Los Angeles Times) – As the planet warms, species around the world are engaged in a race against time to either adapt or move to cooler habitats. Hundreds of them are already losing, according to a recent study in PLoS Biology. As animals and plants move to higher elevations or away from the equator in search of new homes, their historic ranges have shrunk, causing them to go extinct in the areas they left behind. The study, a meta-analysis of dozens of range shift studies, found that 47% of the 976 species surveyed have experienced local extinctions tied to climate change. That means there are none left in the places where they lived for years. “This is not based on a future projection, it’s based on what’s already happened,” said study author John Wiens, an evolutionary biologist and ecologist at the University of Arizona. Since 1880, the average global temperature has increased by about 1.4 degrees Fahrenheit. That’s a modest increase compared with the potential 1 to 5 additional degrees of warming the world could see in the next 100 years, the study argues. With further warming, local extinctions could turn into global ones. “In some ways, this is just the beginning,” he said. [more]

Hundreds of species are already going locally extinct because of climate change, study says Hypothetical example illustrating the two components of a geographic range shift associated with climate change. The large open circle indicates the species’ overall geographic range. Small dark blue circles indicate populations before climate change. After climate change, the overall geographic range is shifted northward (large open circle), both through the range expansion (new populations; small light blue circles) added at the northern, “cold” edge of the species range and range contraction (local extinction of original populations; small red circles) at the southern, “warm” edge of the species range. Similar patterns occur for range shifts along an elevational gradient. Modified from Cahill, et al., 2013. Graphic: John J. Wiens, 2016 / PLOS

ABSTRACT: Current climate change may be a major threat to global biodiversity, but the extent of species loss will depend on the details of how species respond to changing climates. For example, if most species can undergo rapid change in their climatic niches, then extinctions may be limited. Numerous studies have now documented shifts in the geographic ranges of species that were inferred to be related to climate change, especially shifts towards higher mean elevations and latitudes. Many of these studies contain valuable data on extinctions of local populations that have not yet been thoroughly explored. Specifically, overall range shifts can include range contractions at the “warm edges” of species’ ranges (i.e., lower latitudes and elevations), contractions which occur through local extinctions. Here, data on climate-related range shifts were used to test the frequency of local extinctions related to recent climate change. The results show that climate-related local extinctions have already occurred in hundreds of species, including 47% of the 976 species surveyed. This frequency of local extinctions was broadly similar across climatic zones, clades, and habitats but was significantly higher in tropical species than in temperate species (55% versus 39%), in animals than in plants (50% versus 39%), and in freshwater habitats relative to terrestrial and marine habitats (74% versus 46% versus 51%). Overall, these results suggest that local extinctions related to climate change are already widespread, even though levels of climate change so far are modest relative to those predicted in the next 100 years. These extinctions will presumably become much more prevalent as global warming increases further by roughly 2-fold to 5-fold over the coming decades.

Climate-Related Local Extinctions Are Already Widespread among Plant and Animal Species