Tracking Pacific walrus, impacts of early-life stress, and plant traits matter more than origin

Monitoring Pacific Walrus: With the end of summer fast approaching, US Geological Survey (USGS) researchers are once again gearing up to radio-tag walruses on Alaska’s northwestern coast as part of the agency’s ongoing study of how the marine mammals are coping with declining sea ice. “Sea ice is an important component in the life cycle of walruses.  These tracking studies will help us to better understand how top consumers in the arctic ecosystem may be affected by changes in sea ice habitats,” said USGS Alaska Science Center research ecologist Chad Jay in yesterday’s USGS press release. Walruses, which can dive hundreds of feet in search of food, rely on sea ice to rest between dives.  When sea ice is not available, the animals haul out on beaches, something they have been doing more frequently as the extent of sea ice has decreased in recent summers.  Read more at www.usgs.gov/blogs/features/ Far-reaching impact of stress: A new study published in the Proceedings of the Royal Society B. shows that when zebra finches (Taeniopygia guttata) are briefly exposed to stress early in life, the jolt of stress hormones reduced not only their own lifespan, but that of their breeding partner as well.  Pat Monaghan (University of Glasgow) and co-authors report that “only 5 percent of control birds with control partners had died after 3 years, compared with over 40 percent in early stress pairs. Interestingly, a pair’s reproductive success did not seem to be compromised by the early-life exposure to stress. Traits trump plant origins: Nonnative plants often get a bad rap as being a potential threat to wildlife habitat and many state agencies spend time and energy getting rid of them.  An In Press study with Ecological Applications suggests that might be a misplaced effort in some cases.  Jillian Cohen (Cornell University) and colleagues compared the impacts of native and nonnative wetland plants on three species of native larval amphibians.  They found no difference in metamorphosis rates and length of larval period between habitats dominated by native and nonnative plants.  Say the authors: “We suggest that to improve habitats for native fauna managers should focus on assembling a plant community with desirable traits rather than only focusing on plant origin.” Rising sources of nitrate to Gulf of Mexico:  The results of a new study by the US Geological Survey (USGS) published in Environmental Science and Technology found that in spite of decreases along some portions of the Mississippi River Basin, overall efforts to curb this nutrient have been unsuccessful.   Excessive nitrate contributes to the Gulf of Mexico’s dead zones—areas unable to support marine life because of minimal oxygen.  The USGS study...

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Ecological research in images

(Click the below image to view the photo gallery.) This week, the American Museum of Natural History launched the exhibit “Picturing Science: Museum Scientists and Imaging Technologies” which explores the images produced by scientists while performing research. The images range from bug genitalia to staghorn coral (see video at the end of this post). As quoted in a recent Wired Science article, “‘A lot of people come to the museum under [the] impression that we just look at stuff in dusty jars, but that couldn’t be further from the truth,’ said zoologist Mark Siddall, curator of the museum’s new exhibit. ‘There’s a lot of solid, cutting-edge research going on here with incredibly advanced technology.’” Dave Mosher explained in the Wired Science article that images like these are a large part of any scientific endeavor, but often times, these images are filed away—never to be seen by the public. Of course, there are journals that publish images alongside the research articles. While they are all accessible through searches, these images are not typically displayed like those that are being featured in the AMNH’s new exhibit. The above photo gallery presents only some of the images that have been featured in the Ecological Society of America’s journals over the last decade or so. Click on the image to scroll through and learn a bit about the research corresponding with each image. Many of the images featured in ESA journals are taken by the researchers themselves. Browse all of the cover images on ESA’s journals...

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Hybrids in the Arctic
Mar17

Hybrids in the Arctic

Hybridization has led to some of the unique, naturally-occuring species present today, such as the Mallard duck-American Black duck hybrid. Usually this natural process takes generations to produce a new distinct species; however, it is possible for hybrids to emerge within one generation. For example, interspecies breeding could be expedited due to environmental stressors caused by climate change. Species that would not normally come in contact with one another are being pushed into the same habitats—called hybrid zones—due to the removal of physical barriers, like glaciers and ice sheets. The arctic area in particular is experiencing an increase in hybridization due to habitat changes brought about   by climate change. Everyone has seen the photographs of the polar bear clinging to a shrinking piece of ice – the shrinking ice is in fact what is encouraging the influx of non-native species into the Arctic. Polar bears broke off as their own species hundreds of thousands of years ago because they were able to adapt to the colder climate and find food. Charlotte Lindqvist of the University of Buffalo found that polar bears were able to survive the last interglacial warming period; however, Lindqvist added, because the rate of current climate change is so much faster , these Arctic animals are unable to adapt quickly enough. Polar bears are essentially being hit with a 1-2-3 punch. Not only is their habitat diminishing, so too, are their food sources, —negatively impacting their  breeding success. Research has shown that, due to lack of sustenance, female polar bears produce less healthy offspring, and the offspring that survive tend to be smaller in size. Additionally, polar bears may now have to deal with an increased number of grizzly bears. Grizzly bears do not only pose a competitive threat to polar bears but a genetic threat as well. With melting Arctic ice, more polar bears are being forced to remain on land—meanwhile, the warmer temperatures and diverse food sources are enticing grizzlies to move further north. The cross-breeding of polar and grizzly bears could eventually lead to a complete loss of the unique genes of polar bears that have enabled the bear’s survival in the Arctic for so long. Grizzly bears are better suited for the warmer temperatures of the uplands of western North America—that is, compared to Arctic temperatures. With the increase in grizzly population in the Arctic due to warmer temperatures, and the decrease in polar bear population due to habitat constraints, potential cross-breeding could be more likely to occur. While the accepted rule of thumb is that hybrid offspring are unviable—or, unlikely to survive since they are unable to reproduce—there is support in...

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Iridescent beetles, jet-propelled nautiluses and “walking cactus”

The secret to the Japanese jewel beetle’s shine is layers of chitin, threats to the ancient nautilus, a “walking cactus” provides a link between worm and insect, researchers propose drying out Australia’s cane toads, macaques display awareness of their own uncertainty and Florida’s alligator mating season is close at hand. Here is research in ecology and beyond from the last week in February. Iridescent beetle: A study recently published in The Philosophical Transactions of the Royal Society Biological Sciences explored the stacked chitin layers on the body and wings of the Japanese jewel beetle (Chrysochroa fulgidissima). Danielle Venton described the beetle in a Wired Science article: “[S]urface ridges cause visible iridescence, but their primary job is to deflect water or mud. Many are active at night, when their colors can’t be seen. But the Japanese jewel beetle’s surface is smooth, and the study’s authors suspect that iridescence helps these insects recognize each other and find mates.” Read more and see photos at “Gorgeous Jeweled Beetle Reveals Its Tricks.” Jet-propelled nautilus: In the online Scientific American column “Zoologger,” Michael Marshall described the Nautilus pompilius, a shelled cephalopod found in the Indo-Pacific: “Nautiluses mostly scavenge for dead crustaceans, worms and starfish, often digging for them in mud and biting into them with their sharp beaks. They hunt mostly by smell, tracking odours from up to 10 metres away.” This species could be at risk of a severe population decline, said Marshall, due to their slow reproduction rate. Read more at “Jet-propelled living fossil with a problem.” Walking cactus: Jianna Liu from Northwest University in China and colleagues have found the fossil of Diania cactiformis, an organism dubbed the “walking cactus” that may have been related to the velvet worm. “The creature, which dates from around 500 million years ago, is about 6 centimetres long,” wrote Zoë Corbyn in a Nature News article. “It resembles a thin, soft-bodied worm, similar to the lobopodians. But it is also arthropod-like in that it has jointed legs—ten pairs in total. The researchers believe the legs had hardened surfaces, not unlike the tough surfaces of the articulated limbs of crustaceans or insects.’” Read more at “‘Walking cactus’ is anthropods’ lost relative.” Aussie invasions: Researchers are exploring ways of reducing Australia’s cane toad population by drying out the rapidly breeding nonnative pests. As Ed Yong explained in Not Exactly Rocket Science, “While some frogs burrow underground or create protective cocoons, cane toads simply lose water until they die of dehydration. In the heat of Australia’s dry season, they need bodies of water to survive. Fortunately for them, humans have provided them with moisture galore, in the form of...

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Biophysical climate feedbacks revealed at NASW 2009

Science writers from around the country gathered in Austin this week for their annual conference, put on by the National Association of Science Writers and the Council for the Advancement of Science Writing. The meeting attracted some 300 science writers – journalists, editors, communications professionals, etc. – for several days of talking about science and the craft of writing. In the current media environment where newspapers are folding left and right, the meeting is flooded with freelance writers looking for good, newsworthy science. This year the program includes scientists from around the country giving talks on diverse topics such as using yeast to study aging, creating a unified theory of consciousness and examining scientific ethics in the peer-review process. One of the most intriguing talks was given by Kevin Gurney of Purdue University. His project was spurred by the fact that although climate scientists are honing their understanding of the global climate cycle, the role of earths’ lands as a carbon sink is still unclear. Although Earth’s lands absorb about 3 billion tons of human-produced carbon per year, it’s tough to know where it goes. Is it mostly sequestered by vegetation?  Is it captured by soils?  The answers to these questions are important because if we know where the C is going, we can better predict the limits of Earth’s land’s ability to trap carbon.  As Gurney says, if our lands or ocean saturate and stop sequestering carbon, that would effectively make our carbon emissions twice as bad as they are now. Gurney’s Vulcan project attempts to map with high resolution carbon emissions across the United States. The simulation above shows these results mapped on Google Earth – you can zoom into any area and pull up a dictionary entry of its carbon emissions profile. Gurney has also taken these predictions to the next level and extrapolated for individual buildings in a pilot city – Indianapolis, Indiana. Knowing exactly where our carbon emissions are coming from will help us to figure out exactly where it’s going. Gurney hopes that in the future we’ll have an integrated climate forecasting system, just like our current weather forecasts, that will predict the carbon fluxes within any given region at any time. But the most amazing result Gurney presented – and the reason for his talk’s title, “Some Unfortunate Surprises” – has to do with the importance of Artic vegetation for climate change. Gurney’s simulations showed that if we removed all the vegetation in the Earth’s northern latitudes, the resulting exposed snow and ice would in fact create a lighter Earth surface. This change in albedo over the following 100 years would actually...

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Arctic’s big carbon sink could shift to a source

Scientists have known for some time now that the land and seas in the Arctic act as a sink for atmospheric carbon. In a new review paper in the journal Ecological Monographs, ecologists now have a sense of just how much carbon the Arctic has historically handled – up to a whopping 25 percent of the world’s carbon flux. David McGuire of the University of Alaska Fairbanks and the USGS is the lead author on the paper, which reviews 265 published papers related to the Arctic and global carbon cycling. Since the end of the last Ice Age, the Arctic has oscillated between being carbon-neutral, or neither sequestering nor emitting carbon, to trapping up to 800 million metric tons of carbon from the atmosphere and the surrounding ecosystems. This figure shows (a) the extent of permafrost in 2000, (b) the estimate extent of permafrost in 2100 and (c) b overlaid on a. The authors note that recent warming trends have led to a steady decrease in the extent of permafrost, or the frozen underground earth beneath the active soil. Unlike active soils, permafrost does not decompose its carbon; thus, the carbon becomes trapped in the frozen soil. Cold conditions at the surface also slow the rate of organic matter decomposition, allowing Arctic carbon accumulation to exceed its release. The decrease in permafrost thus could tip the current balance toward the Arctic releasing instead of storing carbon. Warmer temperatures will create more active soils, accelerating decomposition and exposing layers formerly frozen in permafrost to decomposition and erosion. And all this doesn’t even touch on the methane problem. As the Arctic thaws, the lands become more waterlogged, encouraging anaerobic metabolism, which releases methane to the air. This is particularly concerning because methane can be up to 23 times more effective as a greenhouse gas than carbon dioxide. At this point, the carbon fate of the Arctic is far from certain, say the authors. Global warming may produce longer growing seasons and promote plant photosynthesis, removing carbon dioxide from the atmosphere. But on the other hand, increasingly dry conditions in the long term might counteract and even overcome this effect through decreased photosynthesis and increased fire prevalence.  Says McGuire: If the response of the arctic carbon cycle to climate change results in substantial net releases of greenhouse gases, this could compromise mitigation efforts that we have in mind for controlling the carbon cycle. Note also that this is the first review paper published by Ecological Monographs, a trend which will continue in future issues. Read more in the ESA press...

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