As sea ice continues to melt, polar bears don’t have the resources to survive extended periods of famine, according to a new study tracking the way the animals move and manage body temperatures.

“A lot of things are changing and that’s why it’s hard to forecast into the future,” said Merav Ben-David, wildlife ecologist at the University of Wyoming, member of The Wildlife Society and coauthor of a new study published last week in Science. But one thing is now sure — the bears don’t have an innate ability to live through longer summers without eating.

A young polar bear on pack ice over deep waters in the Arctic Ocean, October 2009. A new study discounts an old theory about polar bears using “walking hibernation” to get them through summer months without food.
Image Credit: Shawn Harper

“There are limits to how long they can fast,”

Ben-David said. The massive animals tend to manage their yearly diet by periods of intense feast or famine, eating their fill of fat-laden baby seals during the spring when the pups are abundant on sea ice. But once the temperature warms up in the summer and the seals learn how to swim, they evade polar bears (Ursus maritimus) more easily and many bears go hungry for months.

A few decades ago some researchers theorized that the bears get through these lean months through a physical mechanism that amounts to a kind of “walking hibernation” that allows them to conserve the energy they stored from the spring seal hunt.

“We expected a steep and fast decline from 38 to 35 (degrees Celsius), which is typical in hibernating bears,” Ben-David said — a drop in temperature typical of bears when they actually go into hibernation during the winter. But, “we did not find evidence of ‘walking hibernation’ and the associated energy savings that would come with it.”

To conduct the study, the team first caught bears from the Southern Beaufort Sea population in the spring. Between 2008 and 2010, they fitted 26 bears with GPS collars mounted with activity sensors that measured acceleration in a similar way to the walking devices people use to track calorie burning during diets, and temperature loggers. They also surgically implanted temperature loggers into the bears. They then caught the bears again on the shore in August, then once more in October on the ice or on the shore.

The research wasn’t always easy, and the difficulties the team faced in some ways reflect those of the bears themselves. Storms in the area are changing, and while bears usually dig into the snow and ice for shelter, the ice breakup brings more devastating effects. “You have big waves that carry with them big chunks of sea ice,” Ben-David said. “It’s very unpleasant to say the least.”

In fact, at one point some of the ice chunks got washed onto the icebreaker that the researchers used to recapture the bears. The collared bear they were trying to get to was on the ice, but the sea was too violent to approach in several occasions. As a results, they only managed to recapture around half of the 26 animals. In another instance, the weather was so bad that a bear they were following with two cubs emerged with only one after the storm was over.
“Conditions in the Arctic are different today than they were a while back,” Ben-David said.

Bears Use Built-in Wetsuit Technology to Swim

Polar bears have an amazing ability to swim long distances — the team tracked one female bear swimming for nine days straight, at which point she rested for 12 hours then swam for another two. But what surprised the researchers was that sensors showed the bears use a kind of body temperature control similar to penguins during extended swimming periods. The sensors showed the bears’ body temperature dropped to levels as low as 22 degrees Celsius(approximately 70 degrees Fahrenheit) while swimming. “They were reducing blood flow to the periphery of the core, creating an insulating shell that reduces the gradient between the skin and the sea water,” Ben-David said. “It’s the same principle [as wetsuits] but they do it with their own tissues.”

Overall, she said that more research will be needed to determine how long the bears are able to fast, though this will be variable since different populations live under different habitat and food conditions. But this recent study at least shows that “they can’t fast forever during the summer” — a troubling finding as the warming climate pushes the season longer and longer.

Check out a video of some of the research here.

Rutgers University student Tesia Lin recently participated in the TWS Northeast Section’s wildlife field course in Castleton, VT. She reflects on her experience on the U.S. Fish and Wildlife Service (USFWS) Northeast Region’s blog, available here.

Over the past 60 years, globally monitored seabird populations have declined about 70 percent, according to a recent study published in PLOS ONE.

Seabirds include any birds that forage primarily at the sea such as pelicans, terns, gulls, cormorants, albatross and penguins. There are 325 species of seabirds from 14 different families, and about half of these species were represented in this recent study.

As part of the study, researchers gathered literature from journal articles and reports on seabird populations that dated back to the 1950s — albeit most of the data were from the 1970s and 80s — then entered the information into a database. They found that the monitored populations that make up 19 percent of the world’s seabird populations are representative of the total 70 percent global decline of the species.

That’s a loss of about 230 million birds since the 1950s, says study co-author Michelle Paleczny who completed this research as part of her master’s at the University of British Columbia, adding that thedecline wasn’t particularly surprising. “Seabirds are threatened by a suite of different human activities in the world’s oceans,” she said.

Since the 1950s, seabirds have faced a series of threats including fisheries competing with them for food and also tangling the birds in their gear and fish hooks. Other major threats to the birds include plastic and oil pollution as well as negative impacts of climate change and the introduction of non-native predators to islands where seabirds breed. For example, rats introduced to Hawaii prey on seabirds andreduce their population. However, research has shown that removing rats and other non-native predators help seabird populations to rebound.

According to Paleczny, the public can do its part in halting this steep decline by reducing plastic pollution and fossil fuel consumption. In addition, people can lobby the government or vote in ways that would support large marine protective areas that provide refuge for seabirds. “This is particularly important for seabirds because seabirds generally have quite large ranges and lifespans,” she said. “In their lifetimes, they can encounter many different threats and can travel through many different countries.”

Seabirds rely on fish, krill and squid as their food sources — one of the most important types of fishbeing forage fish that are rich in energy including herring, anchovies and sardines. Unfortunately, people also consume these fish that seabirds need to reproduce successfully.

And seabirds are important to marine and terrestrial ecosystems, according to Paleczny. They eat and are eaten by a variety of species, and their absence would impact the food system. They also fertilize the terrestrial ecosystem with their guano that they deposit enriching the biodiversity of the components of the ecosystem, she said.

“Seabirds play an important role in how the marine food web works,” Paleczny said. “Removing seabirds from the food web would alter the overall health of the marine and coastal ecosystems.”

Congress continues its work on creating the fiscal year (FY) 2016 budget. The House and Senate are working on finalizing the Agriculture, Rural Development, Food and Drug Administration, and Related Agencies appropriation bill and the Interior, Environment, and Related Agencies bill. TWS provided testimony regarding these bills in March to encourage appropriations that support wildlife professionals and science-based management and conservation.

The Senate Agriculture appropriations bill was approved by the Appropriations Committee on July 16^th and is awaiting a vote by the full Senate. The House Agriculture appropriations bill was approved by the House Appropriations Committee on July 8 and will be marked up by the full House at a later date. Listed below are the current appropriation levels in each bill for departments, agencies, and programs of particular interest to wildlife professionals.

Status of Agriculture, Rural Development, Food and Drug Administration, and Related Agencies Proposed Appropriations as of July 17, 2015 (in millions of dollars).

The Senate Interior appropriations bill has passed through the Senate appropriations committee and awaits a vote by the whole Senate. The House Interior appropriations bill passed through the subcommittee and full appropriations committee. Heated debate by the full House caused the bill to be pulled from the floor on July 9, leaving an uncertain future for the bill. Listed below are the current appropriation levels designated in these bills for departments, agencies, and programs of particular interest to wildlife professionals.

Status of Interior, Environment, and Related Agencies Appropriations, as of July17, 2015 (in millions of dollars).

These bills also contain riders and amendments that stipulate or forbid certain actions that impact natural resource professionals. The House Interior bill contains amendments that prevent the EPA from implementing new greenhouse gas regulations for new and existing power plants, implementing the “Waters of the United States” rule, and regulating the lead content of ammunition and fishing tackle. The bill also continues a restriction preventing the FWS from making any additional ESA rulemaking on greater sage-grouse, and prevents new closures of public lands to hunting and recreational shooting except in the case of public safety. The Senate Interior bill also contains many of these policy riders.

The outlook for the Interior appropriation bills is hazy at best, as the House bill is no longer actively being considered and the Senate bill is not currently scheduled for a vote. The Agriculture appropriation bills have a more positive outlook, as both bills have passed through the Appropriation Committees and are waiting to be voted on by the full House and Senate.

To keep up to date on the status of these bills and other appropriation bills visit the House Appropriations website and the Senate Appropriations website.

Sources:

Senate Appropriations Committee

House of Representatives Appropriations Committee

People’s identities with political parties have a large influence on their attitudes on environmental issues, according to a new Pew Research Center report — more so than on issues related to biomedical science, food safety or space.

But issues like religious affiliation, knowledge about science and demographic background have strong influences on the public’s views as well.

“In this politically polarized culture, there is a strong temptation to think that people’s partisan connections and their ideology dominate their thinking about every civic issue,” said Cary Funk, associate director for science research and lead author of the new Pew Research analysis, in a release. “What’s striking about these findings is that politics sometimes is at the center of the story about public attitudes and sometimes politics has very little to do with the way people think about science issues in the public arena. We find there are striking differences that center on age, educational attainment, gender, and race and ethnicity.”

Beliefs on climate change are among the most politicized of environmental issues, with 71 percent of Democrats surveyed believing humans are the underlying cause of global warming compared to only 27 percent of Republicans. In terms of race, 70 percent of Hispanics believe humans cause climate change compared to 44 percent of non-Hispanic whites either believe climate change is caused by natural patterns or that there is no solid evidence that climate change is happening. Only 56 percent of Americans with a college degree believed climate change was due to human activity.

In terms of offshore oil drilling, a majority of adults — 56 percent — support expanding the practice. In fact, 72 percent Republicans and those who lean right strongly support more offshore drilling while 39 percent of Democrats and independents leaning left are in favor of it. Overall, support for increased use of fracking has dropped from 48 percent in the 2013 Pew survey to 41 percent.

Factors in which political affiliation had no detectable influence included views on animal testing in science, though this practice was more accepted among people with postgraduate degrees than with those with only a high school diploma or less. In addition, more women than men opposed the practice.