Half of Species Defy Predicted Climate Migrations — SkimNews
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- Toni Lyn Morelli discovered American red squirrels in Bicknell's thrush habitat moving downhill, defying predictions that they would push upslope into the songbird's mountain range as temperatures rose.
- Less than half of species tracked in studies have moved to cooler environments, upending a 30-year ecological consensus that climate change would push wildlife uphill and poleward.
- A 2011 meta-analysis by Chris Thomas at the University of York found 25% of species moving downhill and more than 20% shifting toward the equator rather than away from it, even as the average poleward signal strengthened.
- Steve Beissinger found white-headed woodpeckers moving uphill in northern Sierra Nevada, downhill in the middle, and not at all in the south — a single species responding differently across its own range.
- In the Mojave Desert, bird populations were 'collapsing' in a 2°C-warmed landscape while small mammals thrived in the same conditions, because mammals shelter from extreme heat in burrows and birds cannot.
- Attempts to predict range shifts using behavioral traits — favoring fast-reproducing species thought to 'push at the margins of their ranges' — have failed to produce reliable predictions, according to an analysis by Beissinger and Eric Riddell.
- Conservationists who have been buying cooler, higher-elevation land as 'climate refuges' may be protecting the wrong places, since species movements do not reliably follow the uphill-poleward template.
Why it matters: Land trusts and conservation agencies have spent years acquiring higher, cooler terrain assumed to become climate refuges — but with more than half of species moving in unexpected directions, that acquisition strategy risks protecting habitat that wildlife won't actually use. Ecologists now say precipitation changes, burrowing behavior, and species interactions must be built into models before land purchases and protections can be reliably targeted.
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