Climate Extremes Are Putting Species in Sync — And in Danger

This article discusses the impact that climate change is having on all life on earth.

Growth rings in the ear stones of rockfish and the trunks of trees are giving researchers glimpses of the effects of climate change on biodiversity.

EVERY FEW WINTERS, a high-pressure climate system called the North Pacific High flares up on California’s coast. For several months, northerly winds blow harder than usual down the continent’s West Coast, pushing coastal waters out to sea. The sea level drops, and a soup of nutrient-rich waters rises toward the surface from the depths. Thanks to this coastal upwelling, when the system is strong, everything from phytoplankton to seabirds thrives.

But the same climate feature pushes rain northward, parching the Interior West. In winters when the coast feasts, the Interior West’s land- and river-based systems starve. Alternatively, in winters when the North Pacific High is weak, the coast dries out, while the Interior West flourishes under heavy precipitation. Many Western ecosystems — from coastal ecosystems to landlocked forests and snow-dependent rivers — are in sync with the oscillating nature of the North Pacific High. That means that, even if they are nowhere near each other, scattered populations of the same species of trees will all seed at the same time, or butterflies of the same species will find food and flourish, using cues from this erratic climate phenomenon.

Now, by studying growth rings in the ear stones of long-lived fish and the trunks of ancient trees, researchers have found that the North Pacific High may be becoming more variable and driving a bigger swath of Western ecosystems to biological synchrony — a deceptively nice-sounding situation wherein disparate populations operate on the same clock despite being separated by distance. Unfortunately, synchrony could harm the West’s biodiversity, because it eliminates the natural variation that makes species resilient. And it is only expected to increase with continued human-caused climate change.

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