Another great NPR video on our Sea Otter – Climate change work…
When people talk about sea otters, the words “cute,” “cuddly,” and “curious” often come to mind. But now you can add another descriptor to that list — climate change fighters.
This press release from Ecology nicely summarizes our recent Ecology paper in a forum discussing the fate of Yellowstone’s migratory elk.
“I think Middleton has an intriguing idea, and it might be what’s happening. We offer another hypothesis that also fits the data that they have. He says it’s climate change on the summer range and more predators on the summer range. I think it’s because there is irrigation that provides the sedentary elk with food. And I think it’s also that there is predator control outside the park,” said Wilmers.
While wolves and grizzlies have been thriving inside the park, predator control measures have intensified outside the park, Wilmers said. “My hypothesis is that in that crucial winter period, the migrants are coming down to range that the resident elk have already been feeding on all summer, and now they are competing for in the winter,” he said. To distinguish between these two stories would require hypothesis testing, he said – pitting them against each other and testing them with more data.
Read the entire press release here.
Though Ecology 101 tells us that healthy ecosystems need top predators, researchers are just beginning to understand how the presence—and absence—of wolves affects other species.One study found that wolves may buffer the effects of climate change in Yellowstone National Park, where winters have been getting shorter, by leaving their moose and elk leftovers for eagles, ravens, coyotes and other scavengers. Another papersuggests that the absence of wolves may explain the precarious status of the Canada lynx. No wolves means more coyotes—which hunt snowshoe hares, the lynx’s favorite food—and more elk and deer—which eat the shrubby vegetation that sustain and shelter hares. And a 2011 paper in Biological Conservation supports earlier work showing that wolves in Yellowstone influence the behavior of deer and elk, releasing grazing pressure on vegetation, which in turn increases songbird habitat and diversity.
Read the full article here.
From KTOO in Juneau Alaska, a public radio piece about our sea otter research with an Alaskan twist. Clink on the play button below to listen.
Designated by the California Air Resources Board, carbon offset credits qualify as environmental processes scientifically proven to reduce atmospheric greenhouse gases.
The board has four carbon offset categories: forestry management, tree planting in urban areas, capture and destruction of methane emissions from livestock manure, and destruction of coolant gases. Whereas the first two directly suck carbon out of the atmosphere, the latter two eliminate existing greenhouse gases.
Legally establishing these categories takes time. The forestry project alone took a decade to make scientific sense within the framework of carbon credits, said board spokesman Stanley Young.
Otters currently do not fit into any of these categories. And Wilmers, an assistant professor in UCSC’s Environmental Studies Department, acknowledges that getting them in the game would be difficult.
“Literally trying to do that in the future would take a lot of work,” he said.
But officials involved in evaluating offset programs for the board say the idea is not entirely out of the question. The board, eventually, intends to expand its list. A wetland management category, for example, is among the most promising potential additions — and has been in the works for several years.
From KUSP, another nice NPR piece about our sea otter research. Clink on the play button below to listen.
From National Geographic, a short well-done article on our recent sea otter – carbon pub.
When hungry sea otters whack spiky urchins against rocks on their chests, the mammals may also be striking a blow against global warming.
By preying on urchins—which themselves devour greenhouse gas-absorbing kelp forests—the sea otters encourage the plants to flourish.
The result? An otter-assisted kelp forest “can absorb as much as 12 times the amount of CO2 [carbon dioxide] from the atmosphere than if it were subject to ravenous sea urchins,” according to the study, published Friday in the journal Frontiers of Ecology and the Environment.
Based on a new analysis of 40 years of data on both otters and Pacific kelp forests off Alaska and Canada, the study concludes that “otters ‘undoubtedly have a strong influence’ on the cycle of CO2 storage,” if only in their local environments.
So are sea otters the new global warming “warriors,” as some headlines have it?
Not exactly, said Jeffrey Dukes of the Purdue Climate Change Research Center in Indiana.
The otter-induced increase in CO2 absorption is “relatively inconsequential in terms of the big picture of climate change,” said Dukes, who wasn’t part of the study. But, he added, it’s “an interesting study identifying how dramatically a predator can alter the cycling of carbon in an ecosystem.”
Study co-author Chris Wilmers, a biologist at the University of California, Santa Cruz, agreed that the offset is “unlikely to have a big effect on global warming” worldwide.
But while otters alone can’t do the job, such seemingly incremental, natural advantages may become ever more important as we look for ways to blunt climate change’s impacts, according to study co-author James Estes, also of UC Santa Cruz.
“The general phenom in which the interactions between species are linked to the carbon cycle,” he said, “is going to be very important.”
From Conservation Magazine, a story about our PLoS Biology article documenting the influence of wolves on scavengers as the climate changes.
Wolves and other top predators may help other species cope with climate change. Milder winters in Yellowstone National Park mean fewer elk (Cervus elaphus) die late in the season, which is tough on bald eagles (Haliaeetus leucocephalus), grizzly bears (Ursus arctos), and other scavengers that depend on the carcasses.
New research shows that wolves help scavengers by killing elk and thus providing more late-winter carrion. “Wolves act to retard the effects of a changing climate on scavenger species,” say Christopher Wilmers and Wayne Getz of the University of California, Berkeley, in PLoS Biology.
Many scavengers — from ravens (Corvus corax) and bald eagles to grizzly and black bears (Ursus americanus) — rely on carrion to get them through the winter in Yellowstone. However, without gray wolves (Canis lupus), carrion got scarcer as late winters got milder because deaths of elk depended primarily on snow depth. But after wolves were reintroduced in 1995, they once again became the primary cause of elk death and thus carrion availability.
To see whether wolves could buffer the impact of climate change on late-winter carrion, Wilmers and Getz analyzed 55 years of weather data from northern Yellowstone National Park, which has the park’s largest elk herd (at perhaps 10,000) and nearly 100 wolves. The researchers then estimated carrion availability with and without wolves by using models that accounted for factors including snow depth, wolf pack size, and elk kill rate as well as changes in the wolf and elk populations.
The weather analysis showed that Yellowstone’s winters have gotten shorter and milder, with shallower snow in the late winter months of March and April. The models confirmed that wolves do buffer the impact of milder winters on carrion availability: late-winter carrion drop-ped sharply as temperature increased without wolves but largely rebounded with them. Specifically, March elk deaths declined 27 percent without wolves vs. only four percent with wolves; April elk deaths declined 66 percent without wolves vs. only 11 percent with wolves.
“Late winter carrion in Yellowstone will decline with or without wolves, but by buffering this reduction, wolves extend the timescale over which scavenger species can adapt to the changes,” say Wilmers and Getz. They are now testing whether scavenger populations are in fact higher in areas where wolves have been reintroduced.
This work also shows that there is no substitute for intact ecosystems. “Their conclusions challenge the notion that human hunting serves as a surrogate to wild carnivore predation. Wolves distribute carrion widely in time and space, whereas modern human hunters do not,” says Douglas Smith of the National Park Service, who leads the Yellowstone Wolf Project.