Image left: A desert tortoise, Gopherus agassizii.  (Image by Mike Jones, courtesy Encyclopedia of Life)

“Roads are barriers to dispersal for lots of species and usually it takes many generations to show up in the genetic structure of an animal,” says one of the paper’s co-authors Emily Latch, a postdoctoral researcher at the Smithsonian Conservation Biology Institute’s Center for Conservation and Evolutionary Genetics, and now an assistant professor at the University of Wisconsin-Milwaukee. “Because tortoises have such a long life span, we didn’t think the roads would influence their genetic structure so quickly, but they did.”

The study shows for the first time that recent landscape features such as roads “can have rapid effects on the genetic structure of a localized population and are detectible almost immediately,” in as little as one generation, the scientists report. As a result, the scientists conclude, “Roads may become increasingly important in shaping the evolutionary trajectory of desert tortoise populations.”

For the study, DNA samples were taken from 859 tortoises living in an area of 23,969 acres. “A huge number of samples,” for such a small area, Latch says. Data also was taken on each animal’s sex, location, and location elevation and slope.

Image right: A tortoise in the Mojave Desert. (Image courtesy Wikipedia)

The tortoises were sampled as part of a tortoise relocation effort at Fort Irwin Army Training Center and the animals were located by having people walk map transects in the desert. They picked-up, labeled and took data and DNA samples for every tortoise encountered.

“The adult individuals were initially genotyped to develop a baseline genetic database of translocated and resident tortoises so that family groups hatched after the translocations could be identified to particular parents, and the reproductive success of translocated and resident tortoises compared,” says Smithsonian geneticist Rob Fleischer, head of the Center for Conservation and Evolutionary Genetics and senior author on the paper. “This is important to determine if translocation is really an effective mitigation step. It was serendipity that led to our finding a surprising level of genetic structure.”

Roads may inhibit gene flow in desert tortoises by the reptiles being hit by cars, picked up by travelers, and predation and disease associated with pets released by the roadside. Eroded banks and increased vegetation along desert roads also may provide places for the tortoises to burrow and forage for food, causing them to move along a road rather than to cross it.

The article “Fine-Scale Analysis Reveals Cryptic Landscape Genetic Structure in Desert Tortoises,” by Emily K. Latch, William I. Boarman, Andrew Walde, and Robert C. Fleischer appeared recently in the journal PLoS ONE.

-John Barrat

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Image right: Alexander Graham Bell

In 2011, scholars from three institutions—National Museum of American History Curators Carlene Stephens and Shari Stout, Library of Congress Digital Conversion Specialist Peter Alyea and Lawrence Berkeley National Laboratory Scientists Carl Haber and Earl Cornell—came together in a newly designed preservation laboratory at the Library of Congress to recover sound from those recordings made more than 100 years ago. Using high-resolution digital scans made from the original Volta discs, they were able to hear the word “barometer.”

The museum’s collection has about 400 of the earliest audio recordings ever made, including the 200 from Bell’s Volta lab. A reflection of the intense competition between Bell, Thomas Edison and Emile Berliner for patents following the invention of the phonograph by Edison in 1877, these recordings, along with supporting documents, were offered to the Smithsonian by each inventor in his lifetime.

“These recordings were made using a variety of methods and materials such as rubber, beeswax, glass, tin foil and brass, as the inventors tried to find a material that would hold sound,” said Stephens. “We don’t know what is recorded, except for a few cryptic inscriptions on some of the discs and cylinders or vague notes on old catalog cards written by a Smithsonian curator decades ago.”

Image left: Volta Laboratory recording made by Alexander Graham Bell, #287654-11. (Photo by Carl Haber, Lawrence Berkeley National Laboratory)

Now, through a collaborative project with the Library of Congress and Lawrence Berkeley National Laboratory, the mystery of what is on these recordings is being unraveled. To date, the team has successfully submitted six discs—all experimental recordings made by the Volta Laboratory Associates between 1881 and 1885—to the sound recovery process.

The recordings in the museum’s collection are in fragile condition due to their age and experimental nature. Until now, the technology to listen to the recordings without damaging the discs and cylinders was not available. The noninvasive optical technique used in this project to scan and recover sounds was first studied by Berkeley Lab in 2002–2004 and installed at the Library of Congress in 2006 and 2009. The process creates a high-resolution digital map of the disc or cylinder. This map is then processed to remove evidence of wear or damage (e.g., scratches and skips). Finally, software calculates the motion of a stylus moving through the disc or cylinder’s grooves, reproducing the audio content and producing a standard digital sound file. For more information, visit www.irene.lbl.gov.

Recovering sound from the six Volta discs is the first step in an ongoing project to preserve and catalog the museum’s early recording collection and to provide increased access to the collection and its contents for both the academic community and the public. The content of the recordings, studied in conjunction with the innovative nature of the physical discs and cylinders, provides insight into a variety of topics—from the invention process of these well-known 19th-century labs to speech patterns of the late 19th century.

Image right: Electrotyped copper negative disc of a sound recording, deposited at the Smithsonian in October 1881 and sealed in a tin box. Content: Tone; male voice saying: “One, two, three, four, five, six”; two more tones. Click this LINK to listen. (Photo by Brian Ireley)

This project has been made possible with funding from a variety of sources. The National Museum of American History received a special preservation grant from the Grammy Foundation and support from the museum’s Jackson Fund. The museum is looking for additional funding to continue the examination of other recordings in its exceptional collection. The Institute of Museum and Library Services provided funding to Berkeley Lab through a grant to further develop the optical scanning technology and bring it into use in support of collections and special projects around the world.

The Library of Congress, the nation’s oldest federal cultural institution and the largest library in the world, holds nearly 147 million items in various languages, disciplines and formats. The Library serves the U.S. Congress and the nation both on-site in its reading rooms on Capitol Hill and through its award-winning website at www.loc.gov.

Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

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Image right: Northern cardinal (Click to enlarge. All photos by Gerhard Hofmann, Hofmann & Scheffer Photography)

“Animal vocalizations are specifically adapted to both the structural and acoustic characteristics of their local environment,” said Peter Marra, a co-author of the study and an SCBI ecologist. Marra oversaw and helped design the research. “In order to survive and reproduce, it is imperative for birds to be able to transmit their signals to each other. Now it seems they may be having trouble doing so in urban areas.”

Ambient city noise masks certain lower sound frequencies, making it more difficult for birds to hear one another’s calls over long distances. In addition, hard surfaces—such as buildings—can reflect and distort higher frequency sounds by scattering sound waves and creating multiple reverberations. This can confuse birds and make it difficult for them to pinpoint the source of the call.

Image left: Gray catbird

The results of the researchers’ analysis showed that although there was some variation by species, the birds tended to sing higher notes in areas where there was general noise. The birds tended to sing lower and deeper notes, however, in areas where there were many buildings and hard surfaces. But when the two conditions combined, the birds had trouble altering their songs to accommodate both factors.

“At this point we don’t know exactly how birds adjust their songs,” said Jenélle Dowling, an SCBI intern at the time the research was conducted and lead author of the study. “We expect different species, which differ in their capacity to adjust frequency and type, to respond differently to reverberation and noise.”

By vocalizing, birds are able to identify and locate other members of their species, attract mates and defend their territory. So their ability to adapt to urban living could affect their survival. As urban areas develop rapidly, researchers will continue to investigate how sound from these busy areas affects birds and the effects of development on sound transmission.

Image right: House wren

“This is just another example of how humans continue to impact wildlife,” Marra said. “We now need studies to determine if these changes in song translate into differences in reproductive success,” he added.

This research was carried out in conjunction with the Smithsonian’s Neighborhood Nestwatch citizen science project, where participating citizens allow the researchers to use their property as study sites, as well as volunteer their time to assist with data collection.

Dowling, is currently a doctoral candidate at the Cornell Laboratory of Ornithology in New York. Marra is a conservation scientist at SCBI and advised Dowling. They worked in collaboration with researcher David Luther, who is a term assistant professor in the biology department of George Mason University in Virginia.

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Image right: The Smithsonian’s Barro Colorado Island was the site of the first large-scale, long-term forest dyanmics plots. Now there are 42 forest dynamics plots worldwide that use the same methodology, the Smithsonian Institution Global Earth Observatory system managed by the Center for Tropical Forest Science. (Photo by Marcos Guerra)

“Air pollution is fertilizing tropical forests with one of the most important nutrients for growth,” said S. Joseph Wright, staff scientist at the Smithsonian Tropical Research Institute in Panama. “We compared nitrogen in leaves from dried specimens collected in 1968 with nitrogen in samples of new leaves collected in 2007. Leaf nitrogen concentration and the proportion of heavy to light nitrogen isotopes increased in the last 40 years, just as they did in another experiment when we applied fertilizer to the forest floor.”

Nitrogen is an element created in stars under high temperatures and pressures. Under normal conditions, it is a colorless, odorless gas that does not readily react with other substances. Air consists of more than 75% nitrogen. But nitrogen also plays a big role in life as an essential component of proteins. When nitrogen gas is zapped by lightning, or absorbed by soil bacteria called “nitrogen fixers,” it is converted into other “active” forms that can be used by animals and plants. Humans fix nitrogen by the Haber process, which converts nitrogen gas into ammonia—now a principal ingredient in fertilizers. Today, nitrogen fixation by humans has approximately doubled the amount of reactive nitrogen emitted.

Image left: The Smithsonian’s Barro Colorado Island was the site of the first large-scale, long-term forest dyanmics plots. Now there are 42 forest dynamics plots worldwide that use the same methodology, the Smithsonian Institution Global Earth Observatory system managed by the Center for Tropical Forest Science. (Photo by Marcos Guerra)

Nitrogen comes in two forms or isotopes: atoms that have the same number of protons but different numbers of neutrons. In the case of nitrogen, the isotopes are ¹⁴N and ¹⁵N, although only about one in 300 nitrogen atoms is the heavier form. Imagine nitrogen in the ecosystem like a bowl of popcorn. Normally the ratio of popped (light) to unpopped (heavy) kernels stays the same, but when someone starts to eat the popcorn, the lighter, popped kernels get used up first, increasing the ratio of heavy to light kernels (or ¹⁵N/¹⁴N in the case of the ecosystem). Light nitrogen is lost through nitrate leaching and as gases such as N2, and various forms of nitrous oxides or “noxides,” some of which can be important greenhouse gases. In the fertilization study in Panama, mentioned earlier, N₂O emissions were tripled.

“Tree rings provide a handy timeline for measuring changes in wood nitrogen content,” said Peter Hietz from the Institute of Botany at the University of Natural Resources and Life Sciences in Vienna, who faced down a tiger when sampling trees in a monsoon forest on the Thailand-Myanmar border. “We find that over the last century, there’s an increase in the heavier form of nitrogen over the lighter form, which tells us that there is more nitrogen going into this system and higher losses. We also got the same result in an earlier study of tree rings in Brazilian rainforests, so it looks like nitrogen fixed by humans now affects some of the most remote areas in the world.”

“The results have a number of important implications,” said Ben Turner, staff scientist at STRI. “The most obvious is for trees in the bean family (Fabaceae), a major group in tropical forests that fix their own nitrogen in association with soil bacteria. Increased nitrogen from outside could take away their competitive advantage and make them less common, changing the composition of tree communities.”

“There are also implications for global change models, which are beginning to include nitrogen availability as a factor affecting the response of plants to increasing atmospheric carbon dioxide concentrations,” said Turner. “Most models assume that higher nitrogen equals more plant growth, which would remove carbon from the atmosphere and offset future warming. However a challenge for the models is that there is no evidence that trees are growing faster in Panama, despite the long-term increases in nitrogen deposition and atmospheric carbon dioxide.”

Decades of atmospheric nitrogen deposition have caused major changes in the plants and soils of temperate forests in the U.S. and Europe. Whether tropical forests will face similar consequences is an important question for future research.

The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The Institute furthers the understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. Website: www.stri.org.

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Image right: The coral reef crustacean Sadayoshia edwardsii (Photo by Gustav Paulay)

At depths of between 8 and 12 meters (26 to 39 feet), scientists collected dead coral heads from five different locations. At two sites where removing coral is prohibited, the scientists collected man-made sampling devices that had been left in the water for one year. Combined, the coral heads and devices had a surface area of just 6.3 square meters (20.6 square feet), yet 525 different species of crustaceans were found living on them.

Image left: Laetitia Plaisance searches for crustaceans on a dead coral head. (Photo by Christine Hoekenga)

“So much diversity in such a small, limited sample area shows that the diversity of crustaceans in the world’s coral reefs—and by implication the diversity of reefs overall—is seriously under-detected and underestimated,” says Nancy Knowlton, the Sant Chair for Ocean Science at the Smithsonian’s National Museum of Natural History, co-author of the survey that was just published in the journal PLoS ONE.

“We found almost as many crabs in 6.3-square meters of coral as can be found in all of the seas of Europe,” explains Knowlton. “Compared to the results of much longer and labor-intensive surveys we found a surprisingly large percentage of species with a fraction of the effort.” This shows, says Knowlton, that the statistical uncertainty of estimates of the numbers of animals living in the world’s coral reefs “is huge.”

Image right: Nancy Knowlton dismantles a dead coral head in search of crustaceans living inside.

The study is the first biodiversity survey of coral reefs from three tropical oceans to use DNA barcoding. Lead author Laetitia Plaisance of the Smithsonian’s National Museum of Natural History and the Scripps Institution of Oceanography, explains: “Given the urgency of the state of the world’s coral reefs we used DNA barcoding because it is very fast and very cheap,” she says. “We just need to take a bit of tissue from a specimen and sequence it.”

Image left: The coral-reef crustacean Thor ambionensis (Photo by Gustav Paulay)

“DNA barcoding provides a standardized, cost effective method of coming to grips with the staggering diversity of the world’s oceans,” Knowlton explains. “It has enormous potential for use in broad global surveys, allowing us to find out what is living in the ocean now, and to keep track of it in the future.”

Crustaceans collected for the survey were only those the scientists could see, and ranged in size between 5 millimeters and 5 centimeters (0.2 to 1.9 inches) long. All animals from which DNA was sequenced were preserved so they could be examined by taxonomists at a later date.

Image right: A coral-reef crustacean known as Raoulserenea ornata (Photo by Gustav Paulay)

“We collected dead corals because live corals defend themselves from being inhabited by other invertebrates,” Plaisance says. “Live corals have only symbionts—crabs and shrimp—living with them and these animals also defend their coral.”
Once a coral dies its structure becomes covered with algae, sponges, crustaceans, worms, mollusks and other creatures.

Image left: The coral-reef crustacean Pilumnus tahitensis (Photo by Gustva Paulay)

Given the complexity and extent of the world’s coral reefs, the survey covered only a very limited depth and habitat range, Plaisance explains, “and yet we have so many more species than we ever expected.”

Present estimates of reef species diversity are between 600,000 to more than 9 million species worldwide. “We cannot give a new estimate today but we may be able to in a few years,” Plaisance says.

Using man-made sampling structures at some 50 sampling sites around the world, Plaisance is now working with the Smithsonian and the National Oceanographic and Atmospheric Administration on another survey that will include all of the many organisms that live on coral reefs.

“The Diversity of Coral Reefs: What Are We Missing?” was co-authored by Laettia Plaisance, Nancy Knowlton, M. Julian Caley of the Australian Institute of Marine Science; and Russell E. Brainard of the National Oceanic and Atmospheric Administrating.

Sampling locations for this study were: Indian Ocean—Ningaloo, western Australia. Western Pacific Ocean—Lizard and Heron Islands, Great Barrier Reef, Australia. The central Pacific—French Frigate Shoals, northwestern Hawaiian Islands; Moorea, French Polynesia; and the northern Line Islands. The Caribbean—Bocas del Toro, Panama.

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Images: Photos of Michaux’s sumac by Lytton Musselman

Because Michaux’s sumac grows only in areas with few trees where the vegetation has been disturbed, it has long been assumed that its seeds germinate naturally following exposure to the high-temperatures of a brush or forest fire. Decline of this plant has been attributed to the prevention and suppression of brush and forest fires by humans. In Virginia it grows in only two places: on the grounds of the Virginia Army National Guard Maneuver Training Center in Fort Picket and a mowed railway right-of-way in an undisclosed location.

In a recent series of germination experiments, the scientists exposed different sets of Michaux’s sumac seeds to dry heat temperatures of 140, 176, 212, 248 and 284 degrees Fahrenheit, some sets for 5 minutes and other sets for 10 minutes. (The temperatures were determined based on maximum wildfire surface temperatures and burn times recorded in southeastern U.S. forests.) The researchers found that temperatures above 212 degrees F. killed the seeds. Lower temperatures had virtually no impact on breaking the seed’s dormancy.

The highest germination rates—30 percent—occurred after sulfuric acid was poured on Michaux’s sumac seeds and allowed to scarify (dissolve and weaken) the seed coats. This finding, from an experiment done in 1996, has led the researchers to their next experiment using birds. “We are going to feed the seeds to quail and wild turkey to determine if that breaks the seed dormancy,” says Bolin, a research associate with the Department of Botany at the Smithsonian’s National Museum of Natural History and an assistant professor at Catawba College in Salisbury, N.C. Seed passage through the digestive tracts of frugivorous (fruit eating) birds (and exposure to the acid in the bird’s stomachs) may break the physical dormancy of these seeds and help disperse them as well, the scientists write.

The paper “Germination of the federally endangered Michaux’s sumac (Rhus michauxii), authored by Jay F Bolin, Marcus E Jones (Norfolk Botanical Garden, Norfolk Va.,) and Lytton J Musselman (Old Dominion University, Norfolk, Va.) appeared in the Summer 2011 issue of “Native Plants Journal”

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Images left and below: The variation in biodiversity from place to place, called beta diversity, are actually very similar as you move from the tropics to the poles when you account for the number of species present in the first place. (Photos by Christian Ziegler)

“The same ecological processes seem to be working worldwide. The difference is that tropical organisms have been accumulating for vast periods of time,” said Nathan J.B. Kraft, post-doctoral fellow at the University of British Colombia, who led the research team.

“This study shows how collecting data using the same methods at sites around the world, similar to what we do at the Center for Tropical Forest Science–Smithsonian Institution Global Earth Observatories Network, offers new insights into the processes that shape ecological communities,” said Comita, formerly a post-doctoral fellow at the National Center for Ecological Analysis and Synthesis, now an assistant professor at The Ohio State University. “We found that measurements of variation in biodiversity from place to place, called beta diversity, are actually very similar as you move from the tropics to the poles when you account for the number of species present in the first place.”

Forests in Canada and Europe may have much more in common with tropical rainforests than previously believed. “We see that biodiversity patterns can be explained not by current ecological processes, unfolding over one or two generations, but by much longer-term historical and geological events,” said Kraft, who will join the faculty at the University of Maryland next year.

“Fossils tell a similar story,” said STRI scientist, Aaron O’Dea, co-author, with Willem Renema and others, of a 2008 article in Science showing that marine biodiversity hotspots could be traced back to ancient areas of tectonic activity. “Geological history reveals that glaciations and mass extinctions have lasting effects on the structure of biological communities. It bears witness to the devastation that occurs when accumulated biodiversity is lost: a threat we are facing today.”

The team, which also included researchers from institutions in the U.S., Canada and New Zealand, was supported by the U.S. National Center for Ecological Analysis and Synthesis and the U.S. National Science Foundation.–Beth King, Smithsonian Tropical Research Institute

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What’s possibly the most calming yet nerve-racking job in the world? Come behind the scenes of the Smithsonian’s Freer Gallery of Art to find out!

The conservation and scientific research of ancient Asian art takes a large team of experts from many fields. In order to bring thousands of treasures from the East to the galleries of the Smithsonian in downtown Washington, D.C., several critical steps toward ensuring the objects’ continued longevity must be taken.

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