In Search Of Wildlife-friendly Biofuels: Are Native Prairie Plants the Answer?

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ScienceDaily (Oct. 1, 2009) — When society jumps on a bandwagon, even for a good cause, there may be unintended consequences. The unintended consequence of crop-based biofuels may be the loss of wildlife habitat, particularly that of the birds who call this country's grasslands home, say researchers from Michigan Technological University and The Nature Conservancy.

In a paper published in the October 2009 issue of the journal BioScience, David Flaspohler, Joseph Fargione and colleagues analyze the impacts on wildlife of the burgeoning conversion of grasslands to corn. They conclude that the ongoing conversion of grasslands to corn for ethanol production is posing a very real threat to the wildlife whose habitat is being transformed. One potential solution: Use diverse native prairie plants to produce bioenergy instead of a single agricultural crop like corn.
"There are ways to grow biofuel that are more benign," said Flaspohler, an associate professor in the School of Forest Resources and Environmental Science at Michigan Tech. "Our advice would be to think broadly and holistically about the approach you use to solve a problem and to carefully consider its potential long-term impacts."
The rapidly growing demand for corn ethanol, fueled by a government mandate to produce 136 billion liters of biofuel by 2022—more than 740 percent more than was produced in 2006—and federal subsidies to farmers to grow corn, is causing a land-use change on a scale not seen since virgin prairies were plowed and enormous swaths of the country's forests were first cut down to grow food crops, the researchers say.
"Bioenergy is the most land-intensive way to produce energy, so we need to consider the land use implications of our energy policies," said Fargione, lead scientist for The Nature Conservancy's North America Region.
Whether land used to grow corn for ethanol causes a loss of wildlife habitat depends on the type of land use it replaces. Most of the recent expansion in land planted to corn involves land previously used to grow other crops. But there is evidence that more and more land that had been enrolled in the federal Conservation Reserve Program (CRP) is also being converted to crop production.
CRP is a voluntary program that pays rent to landowners to convert their agricultural land to natural grasslands or tree cover, reducing soil erosion, improving water quality and benefiting wildlife. In September 2007, the amount of land enrolled in the CRP peaked at 36.8 million acres.. Just one month later, in October 2007, CRP lands had declined by 2.3 million acres. And the Food, Conservation and Energy Act of 2008 capped CRP land at 32 million acres by 2010.
CRP land has been shown to help native birds survive and thrive. CRP lands have added an estimated 2.1 million ducks annually to the fall flight over North America's prairies. On the other hand, converting CRP land to cropland threatens the grassland birds and mammals there, Flaspohler and Fargione's paper says. A study of the value of CRP land to grassland birds in North and South Dakota indicated that nearly two million birds of five species would be lost without the CRP in those two states.
Conversion of grassland to corn also has a potentially significant negative impact on freshwater ecosystems. Intact grasslands retain soil and nitrogen. Land planted continuously to corn releases significant amounts of nitrates to freshwater systems. When these nitrogen-laden waters real the Gulf of Mexico, they contribute to algal blooms, creating "dead zones" where low oxygen levels make it difficult for fish and other aquatic wildlife to survive. Soil draining off cropland increases sediment in fresh water, raising temperatures and degrading the habitat of fish such as trout.
What's the solution? There are at least two ways to produce bioenergy without destroying wildlife, habitat, the researchers say. One is to use biomass sources that don't require additional land, such as agricultural residues and other wastes from municipal, animal, food and forestry industries.
Another is to grow native perennials such as switchgrass and big bluestem. The natural diversity of prairie plants offers many benefits, including increased carbon storage in the soil, erosion control and the maintenance of insect diversity, which does double duty by providing food for birds and helping to pollinate nearby crops.
"Bioenergy can be produced in ways that provide multiple benefits to society, including energy production, carbon sequestration and wildlife habitat," Fargione said. "The Conservancy is working to implement on-the-ground demonstrations of grass-based energy systems that would increase the economic value of grasslands and provide an incentive for maintaining and extending grassland habitat."
One concern about using native prairie plants as bioenergy crops is a lower yield per acre planted. However, said Flaspohler, he and fellow Michigan Tech associate professor Chris Webster have collected plant productivity data from12 test fields in southern Wisconsin that should shed light on how field level plant species diversity affects the amount of biomass produced per year.
"We are looking at trade-offs between producing a commodity for use as bioenergy and maintaining important ecosystem services such as soil fertility, water quality, and wildlife habitat," Flaspohler noted. "It was by ignoring unintended consequences that we've now found ourselves highly dependent on a non-renewable fuel source (fossil fuels) that is contributing to climate change. With some foresight and with information on key trade-offs, I think we can make wiser decisions in the future."
Journal reference:
Joseph E. Fargione, Thomas R. Cooper, David J. Flaspohler, Jason Hill, Clarence Lehman, Tim McCoy, Scott McLeod, Erik J. Nelson, Karen S. Oberhauser, and David Tilman. Bioenergy and Wildlife: Threats and Opportunities for Grassland Conservation. BioScience, October, 2009
Adapted from materials provided by Michigan Technological University.

Planet's Nitrogen Cycle Overturned By 'Tiny Ammonia Eater Of The Seas'

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ScienceDaily (Oct. 1, 2009) — It's not every day you find clues to the planet's inner workings in aquarium scum. But that's what happened a few years ago when University of Washington researchers cultured a tiny organism from the bottom of a Seattle Aquarium tank and found it can digest ammonia, a key environmental function. New results show this minute organism and its brethren play a more central role in the planet's ecology than previously suspected. The findings, published online September 30 in the journal Nature, show that these microorganisms, members of ancient lineage called archaea, beat out all other marine life in the race for ammonia. Ecologists now assume that ammonia in the upper ocean will first be gobbled up by phytoplankton to make new cells, leaving very little ammonia for microbes to turn into nitrate.
"Our data suggests that it's the other way around," said co-author Willm Martens-Habbena, a UW postdoctoral researcher. "Archaea are capable of stealing the ammonia from other organisms and turning it into nitrate. Then it's the phytoplankton that take up that nitrate once again."
Ammonia is a waste product that can be toxic to animals. But plants, including phytoplankton, prize ammonia as the most energy-efficient way to build new cells.
The new paper also shows that archaea can scavenge nitrogen-containing ammonia in the most barren environments of the deep sea, solving a long-running mystery of how the microorganisms can survive in that environment. Archaea therefore not only play a role, but are central to the planetary nitrogen cycles on which all life depends.
"Bacterial nitrifiers were discovered in the late 19th century. One century later this other group of nitrifiers is discovered that is not a minor population, it turns out to be the major population," said co-author David Stahl, a UW professor with appointments in the departments of civil and environmental engineering and microbiology. "We have to revise our basic understanding of the nitrogen cycle."
In the tree of life, archaea occupy their own branch. Archaea were discovered only about 30 years ago and were first thought to exist only in extreme environments, such as hot springs or hydrothermal vents. They are now known to be more widespread.
In the early 1990s scientists collecting seawater found strands of genetic material that suggested at least 20 percent of the ocean's microbes are archaea, and circumstantial evidence suggested they might live off ammonia. Stahl's group in 2005 was the first to isolate the organism, which they got from a tropical tank in the Seattle Aquarium, and demonstrate that it can, in fact, grow by oxidizing ammonia. His lab and others have since found the organism in many marine environments, including Puget Sound and the North Sea. The microbe is likely ubiquitous on land and in the seas, they say.
The new experiments show that the organism can survive on a mere whiff of ammonia – 10 nanomolar concentration, equivalent to a teaspoon of ammonia salt in 10 million gallons of water. In the deep ocean there is no light and little carbon, so this trace amount of ammonia is the organism's only source of energy.
"What Willm's work has shown is that these archaea can grow at the vanishingly low concentrations of ammonia found in the ocean," Stahl said. "Until we made the measurements, no one thought it would be possible that an organism could live on these trace amounts of ammonia as a primary energy source."
That finding has two important implications for ocean ecosystems. Scientists knew that something was turning ammonia into nitrate in the deep ocean, but could not fathom what organism might be responsible. Now it appears archaea are those mysterious organisms.
And in the sun-dappled upper ocean waters, it appears that archaea can out-compete phytoplankton for ammonia. The same may be true in soil environments, the researchers say.
The archaea in question are small even by the standards of single-celled organisms. At 0.2 micrometers across, about 8 millionths of an inch, the only life forms smaller are viruses. Martens-Habbena speculates that archaea's size could explain how they are able to survive on such a scant energy supply. The strain used in these experiments is named Nitrosopumilus maritimus, which means "tiny ammonia-oxidizer of the sea."
A better understanding of archaea's lifestyle and role in nitrogen cycles not only would rewrite ecology textbooks. It could also have practical applications, such as devising natural ways to boost a soil's nitrogen content without needing to use chemical fertilizers, or designing sewage treatment plants that employ microbes to remove nitrogenous waste more efficiently, or understanding which microbes produce global-warming gases such as nitrous oxide.
The new findings will also affect the equations used in global climate models, researchers say. Computer models use global cycles of nitrogen and other chemicals to estimate how much carbon dioxide the oceans will absorb and ultimately sink to the bottom of the sea. The new findings suggest that most of the nitrate in the surface water comes from recycling of biomass, and not from the deep water as currently assumed.
"Our data suggest that the carbon pump is weaker than currently assumed, so current climate models may overestimate how much carbon can be absorbed by the oceans," Martens Habbena said.
Other co-authors are the UW's Paul Berube, Hidetoshi Urakawa and Jose de la Torre. The research was funded by the National Science Foundation.
Adapted from materials provided by University of Washington.

Monkeys' Grooming Habits Provide New Clues To How We Socialize.

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ScienceDaily (Oct. 1, 2009) — A study of female monkeys' grooming habits provides new clues about the way we humans socialise. New research, published September 30 in Proceedings of the Royal Society, reveals there is a link between the size of the brain, in particular the neocortex which is responsible for higher-level thinking, and the size and number of grooming clusters that monkeys belong to. The researchers, from the University of Oxford and Roehampton University, have shown that bigger brained female monkeys invest more time grooming a smaller group of monkeys but still manage to maintain contact with other members of their group, even though they have much weaker social bonds with them. In contrast, monkeys of species with smaller neocortices, and therefore less cognitive ability, live in groups with a less complicated social structure.
An analysis of data on the grooming patterns of 11 species of Old World monkeys suggests the relative size of the neocortex is the key factor, rather than overall brain size. The neocortex is connected with cognitive functions, such as learning, memory and more complex thought. In monkeys, species with large neocortices typically live in groups of 25-50 animals, whereas species with small neocortices live in groups of 10-20 individuals.
Species with larger neocortices are able to maintain larger social groups because they can balance a few very intimate friendships against many less close acquaintances. In contrast, species with smaller neocortices cannot manage this, and so have groups that fragment more easily.
The study therefore suggests that, while bigger brained female monkeys concentrate their social effort on core partners in smaller cliques in order to minimize the costs of harassment from other members of the group, their enhanced social skills allow them to exploit weak social links with others in the wider network and maintain good social relations outside their own close-knit groups.
Professor Robin Dunbar, from the Institute of Cognitive and Evolutionary at Oxford University, said: 'These findings give us glimpses into how humans manage the complex business of maintaining coherence in social groups that are much larger than those found in any other primate species. Our neocortex is three times larger than that of other monkeys and apes, and this allows us to manage larger, more dispersed social groups as a result. '
Adapted from materials provided by University Of Oxford.

Rediscovering The Dragon's Paradise Lost: Komodo Dragons Most Likely Evolved In Australia, Dispersed To Indonesia.

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ScienceDaily (Oct. 1, 2009) — The world's largest living lizard species, the Komodo dragon (Varanus komodoensis), is vulnerable to extinction and yet little is known about its natural history. New research by a team of palaeontologists and archaeologists from Australia, Malaysia and Indonesia, who studied fossil evidence from Australia, Timor, Flores, Java and India, shows that Komodo Dragons most likely evolved in Australia and dispersed westward to Indonesia.

The research, which also details new fossil specimens indicating the presence of a new species of giant varanid found on the island of Timor, is published September 30 in the open-access, peer-reviewed journal PLoS ONE.
Author Scott Hocknull, Senior Curator of Geosciences at the Queensland Museum, said Australia is a hub for lizard evolution.
"The fossil record shows that over the last four million years Australia has been home to the world's largest lizards, including a five metre giant called Megalania (Varanus prisca)," Mr Hocknull said.
"Now we can say Australia was also the birthplace of the three-metre Komodo dragon (Varanus komodoensis), dispelling the long-held scientific hypothesis that it evolved from a smaller ancestor in isolation on the Indonesian islands.
"Over the past three years, we've unearthed numerous fossils from eastern Australia dated from 300,000 years ago to approximately four million years ago that we now know to be the Komodo dragon.
"When we compared these fossils to the bones of present-day Komodo dragons, they were identical," he said.
The varanids are a group of giant monitor lizards, which are the world's largest terrestrial lizards and which were ubiquitous in Australasia for over 3.8 million years, having evolved alongside large-bodied, mammalian carnivores, such as Thylacoleo, the 'marsupial lion'. Growing to 2-3 metres in length and weighing around 70 kilos, the Komodo dragon is the last of the truly giant monitor lizards. New fossil discoveries show that the ancestor of the Komodo dragon evolved on mainland Australia, around 3-4 million years ago and then dispersed west to Indonesia. Historically, Australia was home to many other giant monitor lizards, including Megalania (Varanus prisca)—once the world's largest terrestrial lizard but which died out around 40,000 years ago.
"This research also confirms that both giant lizards, Megalania (Varanus priscus) and the Komodo dragon (Varanus komodoensis) existed in Australia at the same time," Mr Hocknull said.
Scott Hocknull and his international team have compared fossil evidence of Komodo dragons and other giant varanids in order to reconstruct the palaeobiogeography of the world's largest land-based lizards. The researchers hope this will have implications for the conservation of the Komodo dragon, which is now found on just a few isolated islands in eastern Indonesia, between Java and Australia, and vulnerable to extinction, probably due to habitat loss and persecution by modern humans over the last few millennia.
It was previously thought that the Komodo Dragon evolved its large size as a response to insular island processes, lack of carnivore competition, or as a specialist hunter of pygmy elephants called Stegodon. However, Hocknull and colleagues report that the ancestor of the Komodo dragon most likely evolved in Australia and spread westward, reaching the Indonesian island of Flores by 900,000 years ago. Comparisons between fossils and living Komodo dragons on Flores show that the lizard's body size has remained relatively stable since then—a period marked by the extinction of the island's megafauna, the arrival of early hominids by 880,000 years ago, and the arrival of modern humans by 10,000 years ago. Within the last 2,000 years, however, their populations have contracted severely.
Further support for the theory that the giant varanids dispersed to Indonesia from Australia comes from the island of Timor, located between Australia and Flores. Three fossil specimens from Timor represent a new (unnamed) species of giant monitor lizard, which was larger than the Komodo dragon (although smaller than Megalania). More specimens of this new Timor-Australian giant lizard are needed before the species can be formally described.
Journal reference:
Hocknull SA, Piper PJ, van den Bergh GD, Due RA, Morwood MJ, et al. Dragon's Paradise Lost: Palaeobiogeography, Evolution and Extinction of the Largest-Ever Terrestrial Lizards (Varanidae). PLoS ONE, 2009; 4(9): e7241 DOI: 10.1371/journal.pone.0007241
Adapted from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS.