Wednesday, August 22, 2012

More studies showing species having unexpected responses to climate change

UC Berkeley's Grinnell Resurvey Project has generated data which allows researchers to assert some unexpected truths about species' responses to climate change.

The general wisdom is that species will move upslope/north to retreat from warming conditions. But that isn't how some species are responding. Two new studies -- "The push and pull of climate change causes heterogeneous shifts in avian elevational range" (Tingley, Koo, Moritz, Rush, and Beissinger) published Aug. 6, 2012, in Global Change Biology, and "Anthropogenic refugia ameliorate the severe climate-related decline of a montane mammal along its trailing edge" (Morelli, Smith, Kastely, Mastroserio, Moritz, and Beissinger) from Aug. 15, 2012, in the Proceedings of the Royal Society B -- look at this puzzle. The first study found as many as 25% of species have shifted in ways not predicted, considering temperature changes. Lead author Morgan Tingley says, "We find that precipitation changes can have a major, opposing influence to temperature in a species’ range shift." The second study looks at Belding's ground squirrel, an animal perceived to be relatively common in the Sierras which has apparently disappeared from 42% of the places where it was recorded in the early 1900s by the original Grinnell survey. Local extinctions appeared more likely where winters are warmer and rain more frequent. UC Berkeley's Toni Morelli elaborates, "[T]he rate of decline is much greater than that seen in the same region for the pika, a small mountain-dwelling cousin of the rabbit that has become the poster child for the effects of climate warming in the contiguous United States."

Eerily, Tingley pointed out in this Aug. 15 article announcing the two studies' release, "More worrisome are the species that have not shifted. How are they adapting? Are they moving, but we just can’t detect it? Or are they slowly declining as environmental conditions gradually become less ideal where they live?"

Meanwhile, the ground squirrel seems to be doing particularly well in places modified by humans-- artificial oases like Mono Lake County Park. In the end, human land management choices might play a bigger role in the survival of a species than global changes in temperature or rain. It should make our state and local governments reconsider the importance of preserving open space-- you never know what species is making its last stand against climate change there.

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