The Bay Area is baking this week. Cue our modern human adaptations to summer: On go the shorts—and the A/C, if we have it. But how are our wild neighbors faring?
A high-pressure system is sitting over much of the West Coast, creating a heat dome: sinking air warms as it compresses and acts like a lid, trapping heat near the surface. The resulting heat wave is by many measures extraordinary, with record temperatures 20–30 degrees above average. Winter is over, and suddenly.
A temperature jolt like this can disrupt the harmonious change of season. If flowers bloom before insects emerge, for example, that could in turn make life harder for the birds that eat those very insects. Such phenological mismatches—a desynchronizing of seasonal biological timing—could stress native flora and fauna. But it might not be so bad in some parts of the San Francisco Bay Area. An absence of drought conditions and a strong maritime layer are likely buffering the region from the most extreme negative effects—though some experts still say they are concerned.
At Coyote Hills Regional Park in Fremont, the recent heat wave has started to dry out the landscape. Wildflowers are blooming earlier than usual. “I’m seeing things moving a little faster than they normally would,” says Christopher Sulots, the park’s supervising naturalist. “Wildflowers like California redbuds and shooting stars have come and gone quickly. Other species we usually see later in the month are already in peak bloom.”
Sulots has seen more mosquitos than usual for this time of year—which is good for swallows who feed on them. Other species like turkeys and ground squirrels are out and about foraging earlier than normal. “We’re seeing some phenological mismatch, but it’s too early to tell just how much. It’ll be something I’ll watch out for,” he says.
“Many of the plants will not respond well to such an abrupt change because they generally have an acclimation period coming out of cool winter conditions into the warmer spring conditions with longer days,” Todd E. Dawson, a professor of integrative biology at UC Berkeley, wrote in an email. “This rapid warming does not allow any adjustment, period.” Some plants will certainly suffer, he added.
Among the vulnerable species are those that require a very specific set of weather conditions this time of year, like California newts.
Merav Vonshak, an ecologist and an entomologist who also serves as the lead organizer for Newt Patrol, says this heat wave coincides with local newts’ migrations from their winter habitats in lakes and other bodies of water to dryland in the foothills. Newt Patrol is a group of community scientists who monitor newt migrations to and from winter habitat in Lexington Reservoir in Los Gatos and summer habitat in the Santa Cruz Mountains. For Vonshak, a heatwave alone wouldn’t be a huge problem, but with the cascading effects of habitat loss, disease and climate change, additional stressors can have an outsized impact.
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“It’s hard to predict, but I’m sure the effects won’t be good,” Vonshak said, who will be closely watching the heat impacts to South Bay newts.
Yet many species are resilient in heat. Peter Tira, a California Fish and Wildlife spokesperson, says the heat wave isn’t alarming wildlife officials. “The main thing we’re seeing as an agency are a lot of bears emerge from their winter dens,” Tira says, noting that warm temperatures have accelerated the springtime end to hibernation. While most black bears in the state are found in the Sierra and foothills, some have moved into the North Bay in the past decade.
Out at Bodega Bay, where rocky shores are lined with critters that like the cool and the wet, things are not too bad, says Jackie Sones, research coordinator at the UC Davis Bodega Marine Reserve. Sones is also a longtime watcher of coastal life, as seen on her photography blog The Natural History of Bodega Head. The heat has so far remained below levels that would impact marine invertebrates, she reports. Highs at Bodega Bay are expected to remain below 70 degrees Fahrenheit, the temperature at which California mussels and surfgrass might start to suffer.
One lucky break: “Marine invertebrates would be most at risk when the warmest air temperatures coincide with low tides in the middle of the day,” Sones wrote in an email. “However, the low tides this week are occurring at the end of the day.”
Marine mammals will also probably be fine, says Giancarlo Rulli, spokesperson for The Marine Mammal Center in Sausalito. “Marine mammals are good at self-regulating their temperature,” he said. Rulli notes that NOAA recently reported a large marine heat wave in the North Pacific. The last marine heat wave from 2013–2016, known as “The Blob,” wreaked havoc on ocean and coastal ecosystems, leading to kelp dieoffs and changes in whale migrations. So far, researchers haven’t seen negative effects from the marine heat wave on marine mammals in Northern California, Rulli said, but potential impacts will be closely monitored.
Precipitation rates throughout the state have been slightly above average so far this year, providing some cushion to the heat’s effects. But the heat will also melt a Sierra snowpack that’s already down to a measly 37 percent of average for this time of year. The California Department of Water Resources is already predicting the “second-lowest April 1 snowpack in recorded California history.” Mountain snow provides the cold, clean water that chinook salmon and steelhead need in California river systems. Low snowpack leads to more challenging conditions for salmonids later in the year.
Temperatures are predicted to fall over the weekend, but stay above average into next week, according to the National Weather Service. The longer the temperature stays above average the more impacts will be seen on local flora and fauna. At Coyote Hills Regional Park, naturalist Sulots is watching for the whiplash that a warming climate has produced. “Things could shift in the exact opposite direction in the next few weeks, which is also not good for plants,” he said.
