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Studies shed light on why species stay or go in response to climate change

		The mountain bluebird shifted upslope in a portion of its range in response to climatic warming. Credit: Morgan Tingley

Two new studies by scientists at the University of California, Berkeley, provide a clearer picture of why some species move in response to climate change, and where they go.

One study, published online Monday, Aug. 6, in the journal Global Change Biology, finds that changes in precipitation have been underappreciated as a factor in driving bird species out of their normal range. In the other study, published today (Wednesday, Aug. 15) in the journal Proceedings of the Royal Society B, researchers found a sharp decrease in range for the Belding's ground squirrel, but noted some surprising areas where the species found refuge.

The two studies exemplify the type of research being explored through the Berkeley Initiative in Global Change Biology, or BiGCB, an ambitious effort to better understand and predict how plants and animals will respond to changing environmental conditions by studying how they have responded to earlier periods of climate change.

The first study's findings challenge the conventional reliance on temperature as the only climate-related force impacting where species live. The authors noted that as many as 25 percent of species have shifted in directions that were not predicted in response to temperature changes, yet few attempts have been made to investigate this.

"Our results redefine the fundamental model of how species should respond to future climate change," said study lead author Morgan Tingley, who began the research as a graduate student in UC Berkeley's Department of Environmental Science, Policy and Management. "We find that precipitation changes can have a major, opposing influence to temperature in a species' range shift. Climate change may actually be tearing communities of organisms apart."

The findings are based upon data gathered from the Grinnell Resurvey Project, which retraces the steps of Joseph Grinnell, founder of the UC Berkeley Museum of Vertebrate Zoology, in his surveys of Sierra Nevada wildlife from the early 1900s. The resurvey project, which began in 2003, was led by Craig Moritz, former UC Berkeley professor of integrative biology, and his colleagues at the Museum of Vertebrate Zoology.

		The Belding's ground squirrel has disappeared from 42 percent of the sites in the California mountains where they were recorded in the early 1900s, but noted that some human-modified areas provided an artificial oasis for the squirrel. Credit: Toni Lyn Morelli

For the bird study, the researchers included 99 species in 77 historic survey sites in Lassen Volcanic, Yosemite and Sequoia national parks, as well as in several national forests. In the century that has passed since the original Grinnell survey, summer and winter temperatures have increased an average of 1-2 degrees Celsius in the Sierra Nevada. Yosemite experienced the most warming — with average temperatures increasing by 3 degrees Celsius — while parts of Lassen actually got cooler and much wetter.

Among the bird species that moved upslope are the Savannah Sparrow, which shifted upward by 2,503 meters, and other meadow species such as the Red-winged Blackbird and Western Meadowlark. The ones that shifted their range downslope include both low-elevation species like the Ash-throated Flycatcher and Western Scrub-Jay, and high-elevation species like the Cassin's Finch and Red-breasted Nuthatch.

"Temperature did not explain the majority of these shifts," said Tingley, who is now a postdoctoral researcher at Princeton University's Program in Science, Technology and Environmental Policy. ''Only when we included precipitation as an explanatory variable did our models adequately explain the movement patterns we observed."

The researchers found that while rising temperatures tended to push birds to cooler regions upslope, increased precipitation, which is more common at higher elevations, pulled them downslope.

"We believe many species may feel this divergent pressure from temperature and precipitation, and in the end, only one wins," said Tingley.

		The ash-throated flycatcher, a low-elevation species, shifted its range downslope in response to climate change, researchers found. Credit: Morgan Tingley

Notably, more than half of the bird species in each of the three study regions did not shift their range despite pressures from climate change. "Moving is a sign of adaptation, which is good from a conservation standpoint," said Tingley. "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?"

The answers are complex, as illustrated by the second UC Berkeley paper about range changes for a species of squirrel found in the mountains of the western United States.

In that paper, researchers again used information obtained from the Grinnell Resurvey Project. Through visual observations and trapping surveys conducted throughout the mountains of California, they discovered that the Belding's ground squirrel had disappeared from 42 percent of the sites where they were recorded in the early 1900s. Extinctions were particularly common at sites with high average winter temperatures and large increases in precipitation over the last century.

"We were surprised to see such a dramatic decline in this species, which is well-known to Sierran hikers and was thought to be fairly common," said study lead author Toni Lyn Morelli, a former National Science Foundation postdoctoral researcher who was based at UC Berkeley. "In fact, the 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."

Morelli added that the squirrels are thriving in areas that have been modified by humans. For example, irrigated Mono Lake County Park serves as an artificial oasis that sustains squirrel populations despite otherwise hot and dry conditions in eastern California.

"As predictions indicate that the range of the Belding's ground squirrel could disappear out of California by the end of the century, these areas might be particularly important for this and other climate-impacted species," said Morelli, who is now a technical advisor for the U.S. Forest Service's International Programs in the Democratic Republic of Congo.

Although the Belding's ground squirrel is widespread, the rapid decline in its distribution is of concern because it is an important source of food for raptors and carnivores. However, the paper suggests that even when climate change causes large range declines, some species can persist in human-modified areas.

"Taken together, these two studies indicate that many species have been responding to recent climate change, yet the complexities of a species' ecological needs and their responses to habitat modification by humans can result in unanticipated responses," said Steven Beissinger, professor at UC Berkeley's Department of Environmental Science, Policy and Management and the senior author on both studies. "This makes it very challenging for scientists to project how species will respond to future climate change."

Funding from the National Science Foundation, National Park Service, and California Landscape Conservation Cooperative helped support this research.

Contact: Sarah Yang
scyang@berkeley.edu
510-643-7741
University of California - Berkeley

 

 

Two new species of owls discovered in the Philippines

		Two new species of owls have been discovered in the Philippines, and an MSU researcher played a key role in confirming their existence. (Top left: Cebu Hawk owl. Bottom right: Camiguin Hawk owl.) Credit: Courtesy of Oriental Bird Club: original painting by John Gale.

Two new species of owls have been discovered in the Philippines, and a Michigan State University researcher played a key role in confirming their existence.

The discovery, which is featured in the current issue of Forktail, the Journal of Asian Ornithology, took years to confirm, but it was well worth the effort, said the paper's lead author Pam Rasmussen, MSU assistant professor of zoology and assistant curator of mammalogy and ornithology at the MSU Museum.

"More than 15 years ago, we realized that new subspecies of Ninox hawk-owls existed in the Philippines," she said. "But it wasn't until last year that we obtained enough recordings that we could confirm that they were not just subspecies, but two new species of owls."

Announcing the finding of a single bird is rare enough. But the discovery of two new bird species in a single paper is so rare that Rasmussen and the other researchers couldn't recall the last time it happened.

The first owl, the Camiguin Hawk-owl, is found only on the small island of Camiguin Sur, close to northern Mindanao. Despite being so close geographically to related owls on Mindanao, it has quite different physical characteristics and voice. At night, it gives a long solo song that builds in intensity, with a distinctive low growling tone. Pairs of owls give short barking duets that start with a growl. They also are the only owls to have blue-gray eyes.

The second new discovery was the Cebu Hawk-owl. This bird was thought to be extinct, as the forests of Cebu have almost all been lost due to deforestation. But it had never been considered a distinct form. Study of its structure and vocalizations confirmed that it was a new species. In fact, it was the unique calling or vocalizations of both owls that confirmed that the new classifications were warranted.

"The owls don't learn their songs, which are genetically programmed in their DNA and are used to attract mates or defend their territory; so if they're very different, they must be new species," Rasmussen said. "When we first heard the songs of both owls, we were amazed because they were so distinctly different that we realized they were new species."

The owls have avoided recognition as distinct species for so long because the group shows complex variation in appearance that had been poorly studied, and their songs were unknown. Both islands are off the beaten path for ornithologists and birders, who usually visit the larger islands that host more bird species.

Sound recordings of both new owl species and those from other islands are available free on AVoCet.

Since the discovery process is both tedious and time consuming, it took a team of scientists and contributors to confirm the owls' existence. The team included individuals from BirdLife International, the Oriental Bird Club, Philippines Biodiversity Conservation Foundation Inc. and Birdtour Asia. Additional support was provided by National Geographic.

Michigan State University has been working to advance the common good in uncommon ways for more than 150 years. One of the top research universities in the world, MSU focuses its vast resources on creating solutions to some of the world's most pressing challenges, while providing life-changing opportunities to a diverse and inclusive academic community through more than 200 programs of study in 17 degree-granting colleges.

 

Contact: Layne Cameron
layne.cameron@cabs.msu.edu
517-353-8819
Michigan State University

 

 

Wild pollinators support farm productivity and stabilize yield

		This is a photo of a bumble bee, known to be a key pollinator in Europe. Credit: Vlada Peneva

Most people are not aware of the fact that 84% of the European crops are partially or entirely dependent on insect pollination. While managed honeybees pollinate certain crops, wild bees, flies and wasps cover a very broad spectrum of plants, and thus are considered the most important pollinators in Europe.

The serious decline in the number of managed honeybees and wild bees reported in Europe over the last few decades has the potential to cause yield decreases with threats to the environment and economy of Europe. The future of the pollination services provided by bees is therefore of serious concern. Effective actions for the mitigation of the pollinator declines need to be taken across Europe.

		This is a snapshot of the English version of the fact sheet. Credit: STEP Project

Although honeybees are important pollinators in large scale plantations, for some crops, including sunflowers, a combination of wild bees and honeybees are essential to provide optimal pollination. Wild bees can support farm productivity when the honeybees can't do the work, for example when their number is insufficient, or when weather conditions prevent them from flying. Moreover, it is well known for several crops, that wild bees are more efficient at pollinating than honeybees, such as mason bees on apples and bumblebees on beans. In addition, wild bees can be a lower cost alternative to honeybees since they do not need to be rented commercially if sufficient high quality pollinator habitat is available in and around farms.

To raise awareness among farmers for the importance of wild pollinators, the EC FP7 project STEP – 'Status and Trends of European Pollinators' published a farmers' factsheet in 15 European languages. The factsheet encourages farmers to utilize the benefits of wild insect pollination services, and thus reduce the risks of relying on the honeybee as a single species for crop production. Farmers are encouraged to take actions to protect pollinators by selecting appropriate agri-environmental schemes and modifying agricultural practices to become more pollinator friendly.

		This is the logo of the STEP project.

Simultaneously, STEP is undertaking a broad-scale survey of the public opinion through online questionnaires available in seven European languages. The survey aims to reveal if, and to what extent, people are aware of the role of pollinators in agricultural ecosystems and the consequences for the environment from the decline of bees and other insect pollinators. People are also being asked to give their opinion on the importance of insect pollination for agriculture to share their perception on the status of pollinators in Europe, their importance for public health, wildlife and the European economy and how important they believe this issue to be. Readers of all nationalities are invited to express their opinions through this online survey.

The STEP project is funded by the European Commission within the FP 7, grant No. 244090 – STEP– CP – FP. More information can be found atthe STEP website.

Contact: Simon G. Potts
s.g.potts@reading.ac.uk
44-118-378-6154
Pensoft Publishers