Now you see them, now you don’t. Hundreds of species have already undergone ‘local extinctions’ because of climate change, according to new a study.
As overall temperatures increase around the world thanks to climate change, plants and animals are starting to shift their geographic range closer to the cooler poles of the planet, or higher up the slopes of mountains. The results are small scale ‘local extinctions’ – where a species cannot be found an area where it once lived, but has not been wiped out completely.
To get a handle on just how widespread these local extinctions are, Prof John Wiens from the University of Arizona has trawled through the published literature pulling together all the available studies examining climate-related shifts in species range. His results, published today in the journal PLOS ONE, capture data from 27 separate studies, covering a total of 976 species around the world. Of those 47 percent had experienced a climate-related local extinction.
A closer look at the data found that local extinctions were almost twice as common among tropical species as among temperate species. This is important as the majority of plant and animal species on Earth live in the tropics.
Read more about the research on Scimex.org.
Running from the heat
The American pika, a small mammal related to hares and rabbits, is one of the the species covered in the research. It is incredibly sensitive to changes in climate and will die within six hours if caught in temperatures above 25.5 °C without shelter. Records collected over the last 100 years show that in the last decade American pika have undergone numerous local extinctions in western North America and have shifted their geographic range to higher elevations at an estimated rate of 145m per decade.
Wiens’ study did not include any New Zealand species, but some from wider Oceania can be found in his analysis. In Papa New Guinea temperature increases have seen the Crested Berrypecker retreat up the slopes of Mt Karimui since the 1960s and now the birds are currently restricted to the immediate vicinity of the summit. A further ∼1°C temperature increase would likely lead to the end of the Crested Berrypecker – and other several other bird species – on Mt Karimui, although populations may persist on taller mountains elsewhere in New Guinea.
The absence of New Zealand species in the research doesn’t mean it isn’t happening here, just that any climate-related local extinctions haven’t been documented in the published literature. This may be due to a lack of long-term species monitoring in New Zealand, a point noted by international researchers earlier this year.
Looking to the future
Wiens’ research highlights the challenges ahead for biodiversity and species conservation, but also portends future social and economic challenges for humans – these climate-related local extinctions could impact species that many human populations depend on for food, such as wheat, rice and corn. By studying what is happening now we can get a better idea of what the future holds for life on Earth. As Wiens puts it:
These local extinctions offer a potentially important but underutilized source of information for the challenging task of predicting patterns of species survival and extinction in the future.
The study’s conclusions in this regard don’t end on a high note.
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.
Featured Image: Marshal Hedin / Flickr