Constantine Alexander's Journal

Climate change alters cast of winter birds

A mix of birds gather around a snow-covered bird feeder during a winter day. According to UW researchers, birds typically found in more southerly regions are gradually pushing north — a likely result of climate change. Photo: Martha Allen/Cornell Lab of Ornithology

By Terry Devitt.

Over the past two decades, the resident communities of birds that attend eastern North America's backyard bird feeders in winter have quietly been remade, most likely as a result of a warming climate.

Writing this week in the journal Global Change Biology, University of Wisconsin-Madison wildlife biologists Benjamin Zuckerberg and Karine Princé document that once rare wintering bird species are now commonplace in the American Northeast.

Using more than two decades of data on 38 species of birds gathered by thousands of "citizen scientists" through the Cornell University Laboratory of Ornithology's Project FeederWatch, the Wisconsin researchers show that birds typically found in more southerly regions are gradually pushing north, restructuring the communities of birds that spend their winters in northern latitudes.

Carolina wrens, which have greatly expanded their wintering range, sit atop a snowman’s head. Photo: Michele Black/Cornell Lab of Ornithology

To the causal observer of backyard birds, the list of species becoming more common includes the readily familiar: cardinals, chipping sparrows and Carolina wrens. These birds and other warm-adapted species, according to Princé and Zuckerberg, have greatly expanded their wintering range in a warmer world, a change that may have untold consequences for North American ecosystems.

"Fifty years ago, cardinals were rare in the northeastern United States. Carolina wrens even more so," explains Zuckerberg, a UW-Madison assistant professor of forest and wildlife ecology.

An estimated 53 million Americans maintain feeding stations near their homes, according to the U.S. Fish and Wildlife Service, suggesting that increases in some species may be attributable to more readily available sources of food. However, that figure has remained constant, reflecting only a slight decline since 1991, indicating that environmental factors beyond the availability of food sources are at play.

The Wisconsin researchers measured the changes over time in the abundance of 38 bird species at feeders in eastern North America, specifically looking at the influence of changes in winter minimum temperature over a 22-year period on the flocks of birds that gather at backyard feeding stations.

"We conclude that a shifting winter climate has provided an opportunity for smaller, southerly distributed species to colonize new regions and promote the formation of unique winter bird assemblages throughout eastern North America," Princé and Zuckerberg write in their Global Change Biology report.

"People will likely start seeing new species in their backyards," says Princé, a UW-Madison postdoctoral fellow. "There can also be subtle changes in species abundance."

The changes in the mix of overwintering bird species is occurring against a backdrop of milder winters with less snow, more variable and intense precipitation events, and a shorter snow season, overall. Climate models predict even warmer temperatures occurring over the next 100 years, with seasonal climate effects being the most pronounced in northern regions of the world.

"We've been able to document in past studies that species are shifting in response to climate change," Zuckerberg says. "This study documents changes in the (winter bird) community structure. If you have a species coming into a new area, it can modify the composition of the community."

A northern cardinal glides above a snowy landscape. “Birds have always been very good indicators of environmental change,” says UW-Madison wildlife biologist Benjamin Zuckerberg. Photo: John Capella/Cornell Lab of Ornithology

In any ecosystem, Zuckerberg notes, removing or introducing even a single species can have a cascade of ecological consequences, many of them unknown.

"These backyard birds are the canaries in the coal mine," Zuckerberg says. "Birds have always been very good indicators of environmental change. Whenever you have a reshuffling of a community of species, you have less of a sense of what change is going to be."

Princé notes that other environmental changes, such as the pervasive human impact on landscape, for example, may also be exerting an influence on the observed changes in the composition of birds attending winter feeding stations in eastern North America.

"Climate change should not be viewed as the sole driver of changes in winter bird communities, but this signal is a pretty strong one for climate change," she explains. "The changes we document are so broad in scope that anything that is occurring at a local level is swamped out by the scale of this analysis."

Citation: Benjamin Zuckerberg and Karine Princé; Climate change in our backyards: the reshuffling of North America's winter bird communities; Global Change Biology 16 OCT 2014, DOI: 10.1111/gcb.12740.

Contact: Benjamin Zuckerberg
608-263-0853
University of Wisconsin-Madison

Study recommends ongoing assessment of impact of offshore wind farms on marine species

A critical element of wind energy planning is developing projects to avoid or minimize negative environmental impacts, particularly to protected marine species. Credit: University of Maryland Center for Environmental Science/Helen Bailey

Read more at: http://phys.org/news/2014-10-ongoing-impact-offshore-farms-marine.html#jCp

A critical element of wind energy planning is developing projects to avoid or minimize negative environmental impacts, particularly to protected marine species. Credit: University of Maryland Center for Environmental Science/Helen Bailey

Read more at: http://phys.org/news/2014-10-ongoing-impact-offshore-farms-marine.html#jCp

 

Offshore wind power is a valuable source of renewable energy that can help reduce carbon emissions. Technological advances are allowing higher capacity turbines to be installed in deeper water, but there is still much unknown about the effects on the environment. In a recent paper, University of Maryland Center for Environmental Science researcher Helen Bailey and colleagues review the potential impacts of offshore wind developments on marine species and make recommendations for future monitoring and assessment as interest in offshore wind energy grows around the world.A critical element of wind energy planning is developing projects to avoid or minimize negative environmental impacts, particularly to protected marine species.

A critical element of wind energy planning is developing projects to avoid or minimize negative environmental impacts, particularly to protected marine species. Credit: University of Maryland Center for Environmental Science/Helen Bailey

Read more at: http://phys.org/news/2014-10-ongoing-impact-offshore-farms-marine.html#jCp

A critical element of wind energy planning is developing projects to avoid or minimize negative environmental impacts, particularly to protected marine species.  Credit: University of Maryland Center for Environmental Science/Helen Bailey

Offshore wind power is a valuable source of renewable energy that can help reduce carbon emissions. Technological advances are allowing higher capacity turbines to be installed in deeper water, but there is still much unknown about the effects on the environment. In a recent paper, University of Maryland Center for Environmental Science researcher Helen Bailey and colleagues review the potential impacts of offshore wind developments on marine species and make recommendations for future monitoring and assessment as interest in offshore wind energy grows around the world.

"As the number and size of offshore wind developments increases, there is a growing need to consider the consequences and cumulative impacts of these activities on marine species," said Helen Bailey, lead author and research assistant professor at the University of Maryland Center for Environmental Science's Chesapeake Biological Laboratory. "It is essential to identify where whales, dolphins and other species occur to help avoid adverse impacts and to continue to monitor their response to the construction and operation of wind turbines."

The loud sounds emitted during pile driving could potentially cause hearing damage, mask communication or disorient animals and fish as they move out of the area to avoid the noise. There is also a risk of marine animals being injured by ships or being disturbed by vessel movements associated with surveying and installation activities. On the other hand, wind turbines may act as artificial reefs and increase food sources. They could also potentially provide a de facto marine reserve thanks to restrictions on boating and fishing surrounding the wind turbines.

"A critical element of wind energy planning is developing projects in such a way that we avoid or minimize negative environmental impacts those installations may cause," said Tom Miller, director of the University of Maryland Center for Environmental Science's Chesapeake Biological Laboratory. "Making these decisions requires a year-round understanding of the species that frequent the area, particularly for protected species that are sensitive to sound, such as marine mammals."

Few studies have measured the response of marine species to offshore wind farm construction and operation, and none yet have assessed the longer terms impacts to the population of marine animals. The researchers recommend strategically targeted data collection and modeling to answer questions about impacts on marine species to help regulators make decisions, particularly in countries where the implementation of offshore wind energy is still in its early stages, such as the United States.

One such project begins this fall off the coast of Maryland where underwater microphones will be anchored to the ocean floor to continuously record sounds produced by large whales and other marine mammals. Led by Bailey, the study will collect two-years of baseline data that can be used to inform the design of wind farms, how to minimize the impact of construction noise and environmental impacts, and how to facilitate ocean planning in the area.

"It is becoming increasingly clear that the most significant impact of offshore wind farms on marine mammals is the avoidance of construction noise," said Bailey. "There needs to be a greater focus on assessing the longer-term impact of any behavioral responses."

Citation: Helen Bailey, Kate L. Brookes and Paul M. Thompson; Assessing environmental impats of offshore wind farms: lessons learned and reccommendations for the future; Aquatic Biosystems 2014 10:08; DOI: 10.1186/2046-9063-10-8.

Contact: Amy Pelsinsky
410-330-1389
University of Maryland Center for Environmental Science

New study shows the importance of jellyfish falls to deep-sea ecosystem

This image depicts hagfish and crustacean amphipods scavenging jellyfish baits in the deep sea. Credit: A. Sweetman, C. Smith, D. Jones

This week, researchers from University of Hawai'i, Norway, and the UK have shown with innovative experiments that a rise in jellyfish blooms near the ocean's surface may lead to jellyfish falls that are rapidly consumed by voracious deep-sea scavengers. Previous anecdotal studies suggested that deep-sea animals might avoid dead jellyfish, causing dead jellyfish from blooms to accumulate and undergo slow degradation by microbes, depleting oxygen at the seafloor and depriving fish and invertebrate scavengers, including commercially exploited species, of food. 

Globally there are huge numbers of jellyfish in the oceans. In some parts of the ocean, jellyfish "blooms" are increasing apparently due to nutrient enrichment and climate change caused by human activities. In recent years, studies have suggested that when jellyfish blooms die-off, massive quantities of jellyfish sink out of surface waters and can deposit as "jelly-lakes" at the seafloor, choking seafloor habitats of oxygen and reducing biodiversity. This latest research shows that the accumulation of dead jellyfish lakes may be unusual, with jellyfish carcasses normally being rapidly consumed by a host of typical deep-sea scavengers such as hagfish and crabs.

"We just had a hunch that dead jellyfish were important to deep-sea ecosystems in some way, even though they are made up largely of water. We therefore decided to film what the fate of jellyfish carcasses were at the seafloor so we deployed deep-sea lander systems with jellyfish bait. When we later retrieved the landers and found no jellyfish attached to the bait plates we were pleasantly surprised. However, our surprise jumped to another level when we looked at the camera images and saw just how fast the jellyfish baits were consumed and the shear number of scavengers that were consuming the baits. It just blew our minds." lead author Andrew K. Sweetman said. Sweetman is a chief senior scientist and research coordinator for deep-sea ecosystem research at the International Research Institute of Stavanger in Norway.

Published October 15 in the prestigious journal Proceedings of the Royal Society: Biological Sciences, the research looked at the response by scavengers to jellyfish and fish baits in the deep-sea along the Norwegian margin. The researchers found that jellyfish and fish baits were consumed equally fast and attracted similar densities of a diversity of scavengers. 

"The speed of the jellyfish scavenging was totally unexpected because earlier, previous observations seemed to suggest that jellyfish carcasses would just rot very slowly at the seafloor. It was also really interesting that the hagfish targeted the most energy-rich parts of the jellyfish, burrowing into the jellyfish carcasses to eat the gonads!" said Craig R. Smith, co-author, designer of the deep-see camera-lander systems used in the study, and a Professor of Oceanography and Pew Fellow in Marine Conservation at the University of Hawai'i at Mānoa, USA. 

 

The study further revealed that the role of jellyfish material could be seriously underestimated in global carbon budgets in the ocean, because jellyfish were removed so quickly that they fail to accumulate at the seafloor, causing scientist to overlook their role in deep-sea food webs.

"Our work shows that previous assessments of the ocean carbon cycle may have missed an important component. Until we saw these photos we thought that the massive amount of jellyfish material was deposited on the seafloor and was essentially taken out of the system – removing carbon rapidly. Our results show that much of this carbon could, in fact, make it into deep-sea food webs, fueling these systems. This is especially important when other food sources to deep-sea ecosystems may be decreasing as our oceans warm" said co-author Daniel Jones, a scientist at the National Oceanography Center in Southampton UK. 

Ultimately, this new research reveals that jellyfish blooms could provide far-reaching, potentially important, food supplements to normal deep-sea food webs, rather than having purely negative impacts on fisheries and marine ecosystem function.

Citation: Sweetman AK, Smith CR, Dale T, Jones DOB. 2014. Rapid scavenging of jellyfish carcasses reveals the importance of gelatinous material to deep-sea food webs. Proceedings of the Royal Society B 281: 20142210. http://dx.doi.org/10.1098/rspb.2014.2210. 

Contact: Marcie Grabowski
808-956-3151
University of Hawaii ‑ SOEST

Past climate change and continental ice melt linked to varying CO2 levels

NASA Goddard Space Flight Center

Scientists at the Universities of Southampton and Cardiff have discovered that a globally warm period in Earth's geological past featured highly variable levels of CO2. 

Previous studies have found that the Miocene climatic optimum, a period that extends from about 15 to 17 million years ago, was associated with big changes in both temperature and the amount of continental ice on the planet. 

Now a new study, published in Paleoceanography, has found that these changes in temperature and ice volume were matched by equally dramatic shifts in atmospheric CO2. 

Using more detailed records than has previously been available, scientists have shown that CO2 levels in this period reached around 500 ppm (parts per million), the same level that the Intergovernmental Panel on Climate Change (IPPC) projects for the end of the century. 

Lead author Rosanna Greenop, from Ocean and Earth Science at the University of Southampton, says: "The drivers of short term, orbital-scale temperature and ice volume change during warm periods of the Earth's history have never been analysed before. Here we are able to show that in the same way as the more recent ice ages are linked with cycles of CO2, it also plays an important role in cyclical climate changes during warm periods."

Researchers also showed that at low levels of CO2, ice volume varied strongly, but at higher levels, there was little or no additional change in volume. The authors of the study hypothesis that there must be a portion of the East Antarctic ice sheet that varies in volume at the lower end of the CO2 range. However, the absence of additional ice melt at higher CO2 levels suggests that there is also a portion of the ice sheet that remains stable at the maximum CO2 levels. 

Evidence suggests that the northern Hemisphere and West Antarctic ice sheets did not exist during the warm Miocene climatic optimum.

"While we recognise that the Miocene climatic optimum is not a perfect analogue for our own warm future, the geological past does represent an actual reality that the Earth system experienced," says the University of Southampton's Dr Gavin Foster, co-author of the study. "As such the findings of this study have large implications for the stability of the continental ice sheets in the future. They indicate that portions of the East Antarctic ice sheet can act in a dynamic fashion, growing and shrinking in response to climate forcing."

Co-author Caroline Lear, of Cardiff University, adds: "We tend to think of the Antarctic ice sheet as a sluggish ice sheet, but these records show that in past warm climates it has been surprisingly sensitive to natural variations in carbon dioxide levels."

Citation: Rosanna Greenop, Gavin L. Foster, Paul A. Wilson, Caroline H. Lear; Middle Miocenne climate instability associated with high-amplitude CO2 variability; Paleoceanography, September 2014; DOI: 10.1002/2014PA002653. 

Contact: Steven Williams
0238-059-2128
University of Southampton

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New forecasting method: Predicting extreme floods in the Andes mountains

Condor Flight by Torres Del Paine. Photo by Paulo Fassina (CC).

This might allow for improved disaster preparedness. As the complex systems technique builds upon a mathematical comparison that can be utilised for any time series data, the approach could be applied to extreme events in all sorts of complex systems.

"Current weather forecast models cannot capture the intensity of the most extreme rainfall events, yet these events are of course the most dangerous, and can have severe impacts for the local population, for example major floods or even landslides," says lead author Niklas Boers of the Potsdam Institute for Climate Impact Research (PIK). "Using complex networks analysis, we now found a way to predict such events in the South American Andes."

When the monsoon hits South America from December to February, it brings moist warm air masses from the tropical Atlantic. Travelling westwards, these winds are blocked by the steep Andes mountains, several thousand metres high, and turn southwards. Under specific air pressure conditions, the warm air masses, loaded with moisture, meet cold and dry winds approaching from the south. This leads to abundant rainfall at high elevations, resulting in floods in the densely populated foothills of the Bolivian and Argentinian Andes. "Surprisingly, and in contrast to widespread understanding so far, these events propagate against the southward wind direction," says Boers.

'Big Data' analysis of observational time series from satellites

The international team of scientists performed a 'Big Data' analysis of close to 50,000 high-resolution weather data time series dating from the 15 years since high quality satellite data became available, generated by NASA together with the Japan Aerospace Exploration Agency. "We found that these huge rainfall clusters start off in the area around Buenos Aires, but then wander northwestward towards the Andes, where after two days they cause extreme rainfall events", says Boers. The new method makes it possible to correctly predict 90 percent of extreme rainfall events in the Central Andes occurring during conditions of the El Niño weather phenomenon when floods are generally more frequent, and 60 percent of those occurring under any other conditions.

"While the findings were hard to derive, local institutions can now apply them quite easily by using readily available data, which helps a lot," says co-author José A. Marengo of the National Institute for Space Research in Sao Paulo, Brazil. "Major rainfall events can result in floods which for instance in early 2007 alone produced estimated costs of more than 400 million US dollars in the region. It is now up to the affected countries to adapt their disaster preparation planning."

Method can be applied to the climate, but also to financial markets

"Comparing weather data sounds simple enough, but it actually took the new mathematical tool that we developed to detect the intricate connections that lead to the extremes," says co-author Jürgen Kurths, co-chair of PIK's research domain Transdisciplinary Concepts and Methods. "The data was there, but nobody joined the dots like this before. The method provides a general framework that could now be applied to forecast extreme changes in time series of other complex systems," says Kurths. "In fact, this could be financial markets, brain activity, or even earthquakes."

Citation: Boers, N., Bookhagen, B., Barbosa, H.M.J., Kurths, J., Marengo, J.A. (2014): Prediction of extreme floods in the eastern central Andes based on a complex networks approach. Nature Communications, DOI: 10.1038/ncomms6199. 

Potsdam Institute for Climate Impact Research (PIK)

Wild Santa Catalina Island

Catalina Island, CA, USA. Photo by Ipotatol (CC)

Santa Catalina is a rocky island off the coast of the U.S. state of California. The island is 35 km long and 13 km across at its greatest width. The island is located about 22 miles south-southwest of Los Angeles, California. The highest point on the island is 639 on Mt. Orizaba. Santa Catalina is part of the Channel Islands of California archipelago and lies within Los Angeles County. The island's population is 4,096 people, 90 percent of whom live in the island's only city, Avalon. The second center of population is the village of Two Harbors. 

The following video which was filmed on August 22 and 23, 2014, shows some of the marine life that claims Santa Catalina as home.