Cod and climate
July 27, 2016 02:53 PM - University of California - Santa Barbara via EurekAlert!
In recent decades, the plight of Atlantic cod off the coast of New England has been front-page news. Since the 1980s in particular, the once-seemingly inexhaustible stocks of Gadus morhua-- one of the most important fisheries in North America -- have declined dramatically.
In 2008, a formal assessment forecasted that stocks would rebound, but by 2012, they were once again on the verge of collapse. Two years later, the National Oceanic and Atmospheric Administration instituted an unprecedented six-month closure of the entire Gulf of Maine cod fishery to allow stocks to recover.
While overfishing is one known culprit, a new study co-authored by researchers at UC Santa Barbara and Columbia University finds that the climatological phenomenon known as the North Atlantic Oscillation (NAO) is also a factor. And it contributes in a predictable way that may enable fishery managers to protect cod stocks from future collapse. The group's findings appear in the journal PLOS ONE.
Low Zika risk for travelers to Olympics in Brazil, study finds
July 26, 2016 07:23 AM - Michael Greenwood, Yale News
The Zika virus poses a negligible health threat to the international community during the summer Olympic Games that begin next month in Rio de Janeiro, Brazil, according to researchers at Yale School of Public Health (YSPH).
In a worst-case scenario, an estimated 3 to 37 of the thousands of athletes, spectators, media, and vendors traveling to Rio for the Olympics will bring the Zika virus back to their home countries, the researchers concluded.
Bird ranges vary more than thought
July 24, 2016 01:32 PM - University of Massachusetts at Amherst via Science Daily
A new study of population trends among 46 ecologically diverse bird species in North America overturns a long-held assumption that the climate conditions occupied by a species do not change over time. Instead, birds that have increased in abundance over the last 30 years now occupy a wider range of climate conditions than they did 30 years ago, and declining species occupying a smaller range.
A new study of population trends among 46 ecologically diverse bird species in North America conducted by avian ecologist Joel Ralston and colleagues at the University of Massachusetts Amherst overturns a long-held assumption that the climate conditions occupied by a species do not change over time.
Putting the sloth in sloths
July 21, 2016 07:19 AM - Terry Devitt, University of Wisconsin-Madison
Although most of the terrestrial world is covered in trees, there are precious few vertebrates that make the canopy their home and subsist solely on a diet of leaves.
Tree sloths are among the most emblematic tree-dwelling mammals. However, they are best known for their pokey demeanor rather than the fact that they spend the majority of their lives in trees munching leaves. But the slow motion lifestyle of tree sloths, according to a new study, is the direct result of the animal’s adaption to its arboreal niche.
“Among vertebrates, this is the rarest of lifestyles,” says Jonathan Pauli, a University of Wisconsin—Madison professor of forest and wildlife ecology and the senior author of a report to appear in the August 2016 edition of the American Naturalist. “When you picture animals that live off plant leaves, they are almost all big — things like moose, elk and deer. What’s super interesting about arboreal folivores is that they can’t be big.”
Birds on top of the world, with nowhere to go
July 20, 2016 10:57 AM - University of Queensland via EurekAlert!
Climate change could make much of the Arctic unsuitable for millions of migratory birds that travel north to breed each year, according to a new international study published today inGlobal Change Biology.
The University of Queensland School of Biological Sciences' researcher Hannah Wauchope said that suitable breeding conditions for Arctic shorebirds could collapse by 2070.
"This means that countries throughout the world will have fewer migratory birds reaching their shores," Ms Wauchope said.
Arctic breeding shorebirds undertake some of the longest known migratory journeys in the animal kingdom, with many travelling more than 20,000 kilometres per year to escape the northern winter.
The bar-tailed godwit flies from Alaska to New Zealand in a single flight of 12,000 kilometres without landing.
The study predicts that, in a warming world, migratory birds will become increasingly restricted to small islands in the Arctic Ocean as they retreat north.
Quantifying Tree Loss in Sierra National Forest
July 20, 2016 10:37 AM - NASA Earth Observatory
Mass tree die-offs are sparking worries of fire in California’s Sierra Nevada range. An outbreak of bark beetles, along with persistent drought in the state, have caused many evergreen trees to wither and die.
The damage spread rapidly through the mountains in the fall of 2015 after favorable spring conditions (warm and dry) led to a surge in beetle populations, according to Zach Tane, a remote sensing analyst with the U.S. Forest Service (USFS). The beetles burrow under a tree’s bark and lay their eggs. Once they penetrate the tree’s armor (the bark), they begin to gnaw into its living tissue, the phloem.
“Needles don’t turn red the next day. It’s a slow process of the tree dying, and it has to do with life cycle of bark beetle and how long needles can persist in a green state,” said Tane. “As the population of beetles grows, they can overwhelm the natural defenses of a tree. There’s a tipping point—that’s what happened in Colorado and probably what’s happening here.”
Which island holds the greatest concentration of mammals?
July 20, 2016 07:22 AM - Jessica Ramos, Care2
In this scary time of global species extinctions and loss of biodiversity below “safe” levels, The Field Museum recently announced some good news: Luzon Island, an island the size of the Indiana in the Philippines, holds the greatest concentration of mammals. The pressing question now is will we be able to protect this rich biodiversity in time?
Hummingbird vision wired to avoid high-speed collisions
July 18, 2016 04:10 PM - University of British Columbia via EurekAlert!
Hummingbirds are among nature's most agile fliers. They can travel faster than 50 kilometres per hour and stop on a dime to navigate through dense vegetation.
Now researchers have discovered that the tiny birds process visual information differently from other animals, perhaps to handle the demands of their extreme aerial acrobatics.
"Birds fly faster than insects and it's more dangerous if they collide with things," said Roslyn Dakin, a postdoctoral fellow in the UBC's department of zoology who led the study. "We wanted to know how they avoid collisions and we found that hummingbirds use their environment differently than insects to steer a precise course."
Note: Watch a video of the experiments here: https://youtu.be/6Z45BaswaOs
Scientists at UBC placed hummingbirds in a specially-designed tunnel and projected patterns on the walls to figure out how the birds steer a course to avoid collisions when they are in flight. They set up eight cameras to track the movement of hummingbirds as they flew through a 5.5-metre long tunnel.
Trees rely on a range of strategies to hunt for nutrient hot spots
July 18, 2016 03:59 PM - Penn State via EurekAlert!
On the surface, trees may look stationary, but underground their roots -- aided by their fungal allies -- are constantly on the hunt and using a surprising number of strategies to find food, according to an international team of researchers.
The precision of the nutrient-seeking strategies that help trees grow in temperate forests may be related to the thickness of the trees' roots and the type of fungi they use, according to David Eissenstat, professor of woody plant physiology, Penn State. The tree must use a variety of strategies because nutrients often collect in pockets -- or hot spots -- in the soil, he added.
"What we found is that different species get nutrients in different ways and that depends both on that species' type of root -- whether it's thin or thick -- and that species' type of mycorrhizal fungi, which is a symbiotic fungus," said Eissenstat. "What we show is that you really can't understand this process without thinking about the roots and the mycorrhizal fungi together."
Tree species with thicker roots -- for example, the tulip poplar and pine - avoid actively seeking nutrient hot spots and instead send out more permanent, longer-lasting roots. On the other hand, some trees with thinner roots search for nutrients by selectively growing roots that are more temporary, or by using their fungal allies to find hot spots.
Ptarmigan in Colorado have varied reproduction, not likely linked to warming trends
July 15, 2016 02:37 PM - Colorado State University via EurekAlert!
Animals that live at high elevations are often assumed to be at risk for extinction as habitats warm and change. But a new study led by Colorado State University researchers found that ptarmigan, which live in cold ecosystems, are not strongly affected by fluctuations in seasonal weather at two populations studied in Colorado.
The results, published July 15 in the journal PLOS ONE, are surprising, given the general perception of alpine animal populations as vulnerable to recent climate warming, study authors said.
Ptarmigan are grouse that live in cold ecosystems, such as alpine and tundra habitats, said Greg Wann, Ph.D. candidate in CSU's Graduate Degree Program in Ecology and a member of the Natural Resource Ecology Laboratory.
The birds are well-known for changing colors seasonally. In late spring and summer, ptarmigan are brown, and in the fall, they molt into a white plumage to match the surrounding snow. The white-tailed ptarmigan is the smallest species of this type of grouse and is endemic to North America. It is the only ptarmigan that exists in Colorado.