Elk populations in the Yellowstone area are declining and scientists from Montana State University have been trying to identify the cause. Wolves, one of the elks' natural predators, were reintroduced to Yellowstone in 1995. Although some elk are killed directly by wolves, scientists have found that the wolves have also had an indirect effect on elk populations. Where wolves share land with elk, elk have altered their foraging behavior to avoid confronting their predators. This change in foraging behavior has meant that elk are not receiving the nutrition they need and as a result are producing fewer calves each spring.

Instead of grazing on grass in open meadows where they are vulnerable to attacks by wolves, elk now opt for the greater protection of wooded areas where they browse on twigs, branches and shrubs in the relative safety of forest cover. This dietary change is significant—grasses are rich in nutrients and are a high quality food source, especially in winter when it is crucial the elk obtain adequate food supplies. But the twigs, shrubs, and branches they feed on when in wooded areas are a lower quality food source than grasses. During the winter, the elk that feed on woody vegetation cannot obtain enough food to maintain their body weight. As the winter months press on, they loose weight and grow weak. When spring comes, they bear fewer calves.

• Greater Yellowstone Elk-Wolf Study Shows Elk Having Fewer Calves Due to Changes in Nutrition (Eurekalert)

Photo © BirdofPrey / iStockphoto.

During the breeding season, male and female crested auklets (Aethia cristatella) grow a distinct group of bristle feathers on the top of their head. Scientists have for some time known that both sexes show a preference for selecting mates with larger crests. Now, a team of researchers from the University of Alaska Fairbanks have discovered that the larger feathers a male crested auklet has, the lower its stress hormones. This suggests that males with larger crests may be better able to cope with the demands of reproduction, foraging, and competition. As a result, they could be better mates than males with smaller crests and higher stress hormones.

Crested auklets are small seabirds that gather to breed in colonies along the coastlines and islands of the Bearing Sea, North Pacific, and Okhotsk Sea. They nest on cliffs, in boulder fields, and on sea-facing talus slopes. Crested auklets are socially monogomous but Hector Douglas, one of the study's lead authors, noted that females will abandon their current mate in favor of a male with a larger crest:

Douglass and colleagues studied the crested aukets on Big Koniuji in the Shumagin Islands in the Aleutian Chain during June and July of 2002. They collected blood samples from the birds and analyzed them for levels of the stress hormone corticosterone.

The research was published in the April issue of the Journal of Comparative Pysiology B.

• Douglas, H., Kitaysky, A., Kitaiskaia, E., Maccormick, A., & Kelly, A. (2008). Size of ornament is negatively correlated with baseline corticosterone in males of a socially monogamous colonial seabird Journal of Comparative Physiology B, 179 (3), 297-304 DOI: 10.1007/s00360-008-0312-6
• Researchers Tie Crest Size to Seabirds’ Suitability as a Mate (University of Alaska Fairbanks)

Photo © Hector Douglas / University of Alaska Fairbanks. Pair of auklets on a rock on St. Lawrence Island in June of 2007.

New software has been developed that will help wildlife researchers to better identify tigers photographed via remote cameras. The software, developed by experts from Conservation Research Ltd. and the Wildlife Conservation Society, relies on technology similar to that of fingerprint-matching software used by crime investigators.

Camera trap photography is a non-intrusive method for studying animals in their natural habitat. Camera traps are automatic, motion-sensitive cameras that are placed at various locations throughout a study site. They are equipped with infrared triggers that snap an image when an animal wanders through the field of vision.

Camera traps are used extensively to study wild tigers. Images of tigers are captured by the camera trap and researchers inspect the photos to identify individual tigers. Scientists can estimate the sizes of local tiger population by measuring how many times individual tigers are re-photographed. Previously, the process of identifying individual tigers was time-intensive and methodical. But now, this new software enables fast matching of the individual stripe patterns.

The software, available for download at www.conservationresearch.co.uk, has also been applied to zebras, grey seals, cheetahs, whale sharks, wildebeest, salamanders, chital, and crested newts. When used to identify tigers, the software was measured to be up to 95 percent accurate.

• Tracking Tigers in 3-D (Eurekalert)
• Conservation Research

Photo © Wildlife Conservation Society.

The Amazon rainforest is a moist broadleaf forest that blankets 5,400,000 square kilometers of the Amazon River basin in South America. The shear vastness of this forest is difficult to comprehend. It stretches across the boundaries of nine nations—Brazil, Colombia, Peru, Venezuela, Ecuador, Bolivia, Guyana, Suriname, and French Guiana. Its biodiversity is unparalleled—an estimated one in ten animals on the planet inhabits the Amazon rainforest.

The staggering proportions of the Amazon rainforest earns it high rank among the planet's most significant biological repositories of carbon. The old-growth forests of the Amazon basin store an estimated 120 Pg of carbon in their biomass—that's 1.2 x 10¹⁷g of carbon neatly locked-up in rainforest roots, trunks, branches, and leaves (Malhi 2008). The Amazon rainforest is for this reason a key stockpile of carbon, it is an immense carbon sink. But its storage of carbon is anything but stagnant.

Like all forests, the Amazon rainforest breaths. It inhales sunlight and carbon dioxide through photosynthesis. It exhales carbon dioxide through respiration and decomposition. This cycle is quietly comforting if you envision the forest as a large, slumbering organism. Comforting, that is, until you realize that this living organism, this carbon behemoth, is capable of losing its breath. If stressed, it might inhale less or exhale more. The vast Amazon forest may transform from carbon sink to carbon source, and in the process it might pump carbon dioxide skyward at alarming rates.

But for a moment, let's put talk of vast forests and carbon sinks aside and simply consider a single leaf. The leaf I would like to consider is pictured at the right. It is a moisture-stressed leaf and appears to be the only leaf left clinging to a young but fast-fading sapling. It was photographed in November 2005 in the Columbian Amazon during the worst drought to strike the Amazon basin in 100 years.

When this leaf inevitably dropped to the ground and the sapling died, it ceased taking up carbon dioxide from the air to photosynthesize. It decomposed and gradually returned the carbon stored in its cells back into the atmosphere in the form of carbon dioxide. When a single, tiny sapling parches and fades in this manner, the carbon dioxide it releases is minute. But when extreme drought causes widespread leaf loss and tree death, the volume of carbon dioxide that is released may be enough to swell atmospheric carbon dioxide concentrations.

The drought that descended upon the Amazon River basin in 2005 was one such extraordinary event. Its more visible effects were well documented in the mainstream media (see here, here, here, and here for a few examples). There were reports of rivers that had turned to mudflats, boats that became stranded whilst waterways evaporated, and thousands of fish that perished amidst receding currents. At the time, the media attributed the lack of rainfall in the Amazon to climate change, deforestation, and abnormally warm sea surface temperatures in the North Atlantic Ocean. But from a scientific perspective, the true causes and effects of the drought would require methodical analysis to understand.

In 2008, a careful analysis of climatic data surrounding the 2005 drought event was published in Environmental Research Letters by a team of scientists lead by Ning Zeng of the University of Maryland. The figures below (from Zeng 2008) illustrate two key events that occurred in 2005, an abnormally dry Amazon River basin and an abnormally worm tropical North Atlantic Region.

Figure (a) above illustrates just how dry the Amazon basin was in 2005 as compared to mean rainfall measurements for the region over the preceding 25 years (1979-2005). Where the shaded areas are the darkest brown, rainfall deficits were the most pronounced. The regions where the drought was the most devastating were in the western and southern parts of the Amazon basin. Figure (b) above shows the abnormally warm sea surface temperatures in the North Atlantic region, with the more elevated temperatures marked by increasingly darker shades of red.

These two images—one of a dry Amazon basin and another of elevated Atlantic sea surface temperatures—provided the backdrop against which Dr. Oliver Phillips from the University of Leeds and his colleagues ventured into the depths of the Amazonian rainforest. They visited 55 study sites—plots that had been monitored for 25 years as part of the long-term research project RAINFOR. They collected data (such as tree diameter and wood density) at each location and compared it to that of past years. What they found was sites that had previously acted as carbon sinks became carbon sources under drought conditions. The diagram below (from Phillips 2009) articulates this reversal.

Figure A shows that in the years leading up to 2005, the above ground biomass (AGB) at many of the sites was on the increase (they were acting as carbon sinks). Then in 2005, shown in Figure B, there was a reversal of AGB accumulation at many sites (they had transformed to carbon sources). Figure C further isolates the situation in 2005 by showing the difference between 2005 and pre-2005 AGB accumulation. The shaded areas on the map indicate rainfall data (the darker areas reveal regions of more intense drought).

One additional part of the Amazon basin drought story is the atmospheric carbon levels. In 2005, carbon dioxide concentrations crept to the third highest level since records began. Phillips and his colleagues make mention of this in the concluding remarks of their paper (Phillips 2008) but remain cautious about what to conclude from it:

Although the role that the Amazon rainforests play in the global carbon cycle remains cryptic, the droughts of 2005 shed light on how this vast forest ecosystem might respond to and recover in a changing climate.

• Y. Malhi, J. T. Roberts, R. A. Betts, T. J. Killeen, W. Li, C. A. Nobre (2008). Climate Change, Deforestation, and the Fate of the Amazon Science, 319 (5860), 169-172 DOI: 10.1126/science.1146961
• O. L. Phillips et al. (2009). Drought Sensitivity of the Amazon Rainforest Science, 323 (5919), 1344-1347 DOI: 10.1126/science.1164033
• Ning Zeng, Jin-Ho Yoon, Jose A Marengo, Ajit Subramaniam, Carlos A Nobre, Annarita Mariotti, J David Neelin (2008). Causes and impacts of the 2005 Amazon drought Environmental Research Letters, 3 (1) DOI: 10.1088/1748-9326/3/1/014002

Photo (top) © Peter van der Steen. The Amazon forest canopy from above, blanketed in a dawn mist. Photo (bottom) © Peter Vitzthum. Moisture-stressed leaf. Diagram (top) from Malhi 2008. Diagram (bottom) from Phillips 2009.

Forest ecologist Dr. Nalini Nadkarni has a singular passion for trees. For the better part of two decades she has studied the plants and animals that inhabit rainforest canopies around the world. Her research has taken her to the forests of Costa Rica, Papua New Guinea, the Amazon and the Pacific Northwest. Now, she spends much of her time reaching beyond the boundaries of the academic world to engage non-scientists in the preservation of forest species and ecosystems.

Dr. Nadkarni has worked with people from diverse walks of life—poets, artists, and prisoners—on projects that include growing moss, making music about trees, and breeding endangered frogs. You can find out more about Dr. Nadkarni's innovative work via the TED website, which has a terrific video of her talking about the beautiful, fragile world of rainforest treetop ecosystems:

Photo © Avtg / iStockphoto.

Komodo dragons (Varanus komodoensis) are the largest of all lizards, they can grow to lengths of 3m and can weigh as much as 165kg. Komodo dragons belong to the Family Varanidae, a group of reptiles known more commonly as the monitor lizards. Adult Komodo dragons are dull brown, dark grey, or reddish in color, while juveniles are green with yellow and black stripes.

Komodo dragons are carnivores and scavengers. They are the top carnivores in their ecosystems. Komodo dragons occasionally capture live prey by hiding in ambush and then charging their victims, although their primarily food source is carrion. They have good vision and adequate hearing but rely mostly on their acute sense of smell to detect potential prey. Komodo dragons have a long, yellow, deeply-forked tongue and sharp serrated teeth.

Komodo dragons have a rounded snout, strong limbs, and a muscular tail. They establish home ranges of up to 1.9 square meters in area, but they do not defend these territories. When Komodo dragons encounter one another, the dominant lizard (usually the largest male) prevails.

The mating season for Komodo dragons takes place each year during July and August. In September, females dig an egg chamber in which she lays up to 30 eggs. She covers the eggs with leaves and lies over the nest to incubate the eggs. After about 8 months they hatch and the mother provides no additional care. When born, the young are approximately 37cm in length. They are vulnerable to predation by adult Komodo dragons, birds, and mammals. For this reason the young climb up into trees where an arboreal lifestyle gives them refuge from predation until they are large enough to defend themselves.

• Mass: 165kg
• Body Length: 3.1m
• Diet: carnivores, carrion
• Breeding Season: July to September
• Sexual Maturity: 9 years (female)
• Gestation: 8 months
• Number of Offspring: up to about 30
• Predators: Adults have no predators. Juveniles fall prey to large mammals and birds.
• Average Lifespan: 50 years (wild)
• Habitat: tropical savannah forests, open lowland habitat, beaches, dry riverbeds.
• Geographical Range: Indonesian islands of Komodo, Flores, Rinca, and Padar.

• Kingdom: Animalia
• Phylum Chordata
• Class: Reptilia
• Order: Squamata
• Suborder: Autarchoglossa
• Family: Varanidae
• Genus: Varanus
• Species: Varanus komodoensis

Komodo dragons inhabit the Indonesian islands of Komodo, Flores, Rinca, and Padar. They live in tropical savannah forests.

• Burnie D, Wilson DE. 2001. Animal. London: Dorling Kindersley. 624 p.
• Cooke F, Dingle H, et. al. 2004. The Encyclopedia of Animals: A Complete Visual Guide. Los Angeles: University of California Press. 608 p.
• Lawwell L, Fraser A. 2006. Varanus komodoensis, Animal Diversity Web. February 11, 2009.
• Komodo Dragon (National Zoo)

Feathers are unique to birds. They are a defining characteristic of the group, meaning simply that if an animal has feathers, then it is a bird. Feathers serve many functions in birds but most notable is the critical role feathers play in enabling birds to fly. Unlike feathers, flight is not a characteristic restricted to birds—bats fly with great agility and insects fluttered through the air several million years before birds joined them. But feathers have enabled birds to refine flight to an art form matched by no other organism alive today.

In addition to helping to enable flight, feathers also provide protection from the elements. Feathers provide birds with waterproofing and insulation and even block harmful UV rays from reaching birds' skin.

Feathers are made up of keratin, an insoluble protein that is also found in mammalian hair and reptilian scales. In general, feathers consist of the following structures:

• calamus - the hollow shaft of the feather that attaches it to the bird's skin
• rachis - the central shaft of the feather to which the vanes are attached
• vane - the flattened part of the feather that is attached on either side of the rachis (each feather has two vanes)
• barbs - the numerous branches off the rachis that form the vanes
• barbules - tiny extensions from barbs that are held together by barbicels
• barbicels - tiny hooks that interlock to hold the barbules together

Birds have several different types of feathers and each type is specialized to serve a different function. In general, feather types include:

• primary - long feathers located at the tip of the wing
• secondary - shorter feathers located along the trailing edge of the inner wing
• tail - feathers attached to the bird's pygostyle
• contour - (body) feathers that line the bird's body and provide streamlining, insulation, and waterproofing
• down - fluffy feathers located under the contour feathers that serve as insulation
• semiplume - feathers located under the contour feathers that serve as insulation (slightly larger than down feathers)
• bristle - long, stiff feathers around the bird's mouth or eyes (the function of brislte feathers is not known)

Feathers suffer wear and tear as they are exposed to the elements. Over time, the quality of each feather deteriorates and thus comprimises its ability to serve the bird in flight or to provide insulation qualities. So to prevent feather deterioration, birds shed and replace their feathers periodically in a process called molting.

• Attenborough, David. 1998. The Life of Birds. London: BBC Books.
• Sibley, David Allen. 2001. The Sibley Guide to Bird Life & Behavior. New York: Alfred A. Knopf.
• The University of California, Berkely (UCB). 2006 (Accessed Online). Museum of Paleontology.

Carotenoids are a class of over 600 organic pigments that range in hue from red to orange to yellow. Carotenoids are produced in the chloroplasts of plants as well as some algae and bacteria. Examples of plants rich in carotenoids include sweet potatoes, carrots, kale, broccoli, and pumpkins.

Carotenoids function in plants to absorb light energy for use in photosynthesis and also help to protect chlorophyll from degrading. Carotenoids are divided into two subclasses, carotenes (orange and red pigments) and xanthophylls (yellow pigments).

Animals are not able to synthesize carotenoids so they must obtain these compounds by eating plants and other organisms rich in carotenoids. Animals benefit from cartenoids in a number of ways. Carotenoids are responsible for coloration in many animals (notably birds and crustaceans) and this color is often used in courtship as a signal of health of the individual. Carotenoids are also believed to enhance vision and immune systems in some animals.

Some examples of animals whose color results from carotenoids include lobsters, sally lightfoot crabs, greater flamingos, and scarlet ibises.

Photo © Photoblueice / iStockphoto. Sally lightfoot crabs owe their color to carotenoids.

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• Carotenoids Bolster Birds' Feather Color

A new tiger protection effort has been launched by the Wildlife Conservation Society, the World Bank, and the Global Environment Facility. Together, these organizations have committed $2.8 million to tiger conservation under a project called Tigers Forever.

Today, estimates of tiger populations in the wild place their numbers in the region of 5,000 individuals, of which about 2,300 are breeding adults. As recently as a few hundred years ago, wild tigers may have numbered in the region of 100,000 to 500,000 individuals. Tigers are listed as endangered on the IUCN Redlist of Threatened Species.

The Tigers Forever project is breaking new ground by coordinating efforts by a variety of institutions:

The project's objectives are exceptionally concrete: to increase tiger numbers within a selection of sites throughout Asia by 50 percent over the next ten years. Conservationists involved in the project have for the first time placed such finite numbers on their goals. There are currently 800 individuals in the selected sites. The Tigers Forever project sets out to increase tiger numbers in the selected sites to 1,200 individuals.

Photo © Wildlife Conservation Society. Siberian tiger captured by a remote camera in the Russian far East.

• Tiger Gets a Stimulus Plan (Eurekalert)
• Tigers Get a Business Plan (Wildlife Conservation Society)

Until recently, small migratory songbirds, too small to track via satellite, have eluded scientists who wish to follow their annual migrations. Now, a tiny device that senses light levels and records sunrise and sunset times, enables scientists to gain new, detailed insight into songbird migration.

The device, referred to as a 'light-level geolocator', is made of plastic and weights about 1.5 grams. To use it, scientists must first capture several individual birds that they wish to track and attach the geolocators to each bird. They then release the birds back into the wild and wait for the birds to complete their migration. Later, scientists recapture the birds and retrieve the devices. The data is downloaded from the devices and the sunrise and sunset times are analyzed. The sunrise and sunset times are used by scientists to calculate where the birds were at different points during their migration.

Bridget Stutchbury, a professor of biology from York University, Toronto, was the lead author of the study. Stutchbury's team used the the light-level geolocator devices to map the migratory routes of two species, purple martins (Progne subis) and wood thrushes (Hylocichla mustelina). In addition to pioneering a new way to track small birds, the team was able to establish data on the songbirds' speed of migration. They found that the birds migrated more than 300 miles a day, far more than the 90 miles per day that had previously been estimated.

Photo (top) © of Elizabeth Gow. Male wood thrush with a geolocator. Photo (bottom) © of Tim Morton. Female purple martin with geolocator on her back.

• Stutchbury BJ et al. 2009. Tracking Long-Distance Songbird Migration by Using Geolocators. Science. Vol 323(5916) p 896.

In many species of birds, bright, colorful feathers serve as a signal of vitality and as a result the more vibrant birds often are more successful at attracting mates. In species such as house finches, flamingos, scarlet ibises and Northern cardinals, their colorful feathers are the result of a diet rich in carotenoids.

Carotenoids are a class of organic pigments that are produced by plants. These red, yellow, and orange pigments help plants to absorb light energy for photosynthesis and prevent degradation of chlorophyll. But the advantages of carotenoids are not restricted to the plants that synthesize them. Animals that eat plants rich in carotenoids enjoy numerous benefits from these compounds as well.

Carotenoids function as antioxidants and boost the immune system. They serve as coloring agents in many organisms. Numerous species of birds (for example, Northern cardinals, scarlet ibises, house finches, flamingos) feast on carotenoid-rich foods. As a result individuals with the best diets are the most colorful and potentially more successful at attracting mates.

Now, scientists from Arizona State University are investigating several other ways carotenoids might be beneficial to birds. The team, lead by Professor Kevin McGraw, is studying house finches, mallards, and northern pintails.

• Poly Wants a Pigment (Eurekalert)

Photo © Michael Stubblefield / iStockphoto.

Despite their common name, gray wolves (Canis lupus) are a colorful bunch of canines. Their coat color can range from white to gray to black and is regulated by a complex set of genetic factors.

The frequencies of coat colors within a wolf population vary depending on the type of habitat the wolves occupy. For example, wolf packs that live in open tundra habitat consist of primarily light-colored individuals. This enables the wolves to blend in with their surroundings and, in turn, conceal themselves when pursuing caribou, their primary prey. Wolf packs that living in boreal forests contain higher numbers of dark-colored individuals, as their habitat enables the darker colored individuals to blend in.

Of all the wolves' color variations, the black individuals are the most intriguing. Black wolves are so colored due to a genetic mutation at the K locus gene. This mutation causes a condition known as melanism, an increased presence of dark pigmentation which causes an individual to be black (or nearly black).

Black wolves are also intriguing because of their distribution. There are significantly more black wolves in North America than there are in Europe. Until now, there has been little indication of why this distribution difference existed.

To better understand the genetic underpinnings of black wolves, a team of scientists from Stanford University, UCLA, Sweden, Canada and Italy was assembled. The team, lead by Stanford's Dr. Gregory Barsh, analyzed DNA sequences of 150 wolves (about half of which were black) from Yellowstone National Park. What they pieced together turned out to be a suprising genetic story that stretched back tens of thousands of years to a time when humans were breeding domestic dogs in favor of the darker varieties.

It turns out that the presence of black individuals in Yellowstone's wolf packs is the result of historical matings between black domestic dogs and gray wolves. In the past, humans bred dogs in favor of darker, melanistic individuals, thus increasing the abundance of melanism in domestic dog populations. When domestic dogs interbred with wild wolves, they bolstered melanism in wolf populations.

Unravelling the genetic past of any creature is tricky business. Molecular analysis provides scientists the ability to estimate when genetic shifts could have occurred in the past, but attaching a firm date to such events is not possible. Based on genetic analysis, Dr Barsh's team estimates that the melanism mutation in canids arose sometime between 12,779 and 121,182 years ago (with the most likely date being 46,886 years ago). Since dogs were domesticated around 40,000 years ago, this evidence fails to confirm whether the mutation arose first in wolves or in domestic dogs.

But the story does not end there. Because melanism is far more prevalent in North American wolf populations than it is in European wolf populations, it suggests that the cross between domestic dogs populations (rich in melanistic forms) likely occurred in North America. Study co-author Dr. Robert Wayne has dated the presence of domestic dogs in Alaska to about 14,000 years ago. He and his colleagues are now investigating ancient dog remains from that time and location to determine whether (and to what degree) melanism was present in those ancient domestic dogs.

Scientists studying sedimentary rocks in south Oman have discovered high concentrations of steroids that they believe were produced by ancient, multicelluar animals. The team proposes that the fossilized steroids, which date back 635 million years, were produced by sponges, one of the most basic forms of animal life on Earth.

Sponges (Phylum Porifera) are a diverse group of aquatic animals, with about 5000 known species worldwide. Sponges are primarily marine creatures but there are also a few species of freshwater sponges. Sponges are sessile animals that attach themselves to the sea floor and feed by filtering food from the surrounding water.

The discovery of the ancient sponge steroids in Oman suggests that multi-celled animals were present on Earth 100 million years prior to the Cambrian Explosion, a period in our planet's history when animal life diversified rapidly. The steroids that were discovered are of a type present in the cell membranes of sponges. They function to provide the sponge with structural support.

The research team included scientists from University of California, Riverside, Massachusetts Institute of Technology, and other institutions. The study was headed by Gordon Love, an assistant professor of Earth sciences from MIT. Love hopes to focus future study efforts on analyzing sedimentary rocks that are between 850 and 635 million years old. He hopes that by studying these ancient sediments, he and is colleagues will be able to further their understanding of the first multicellular animals to have inhabited Earth.

Researchers Find Earliest Evidence for Animal Life (Eurekalert)

Photo © Love lab / UC Riverside.

Scientists studying southern right whales (Eubalaena australis) have discovered that mothers teach their young where to feed. Southern right whales gather off the coast of the Argentina’s Peninsula Valdés between June and December each year. The site serves as a calving ground, with peak calving occurring in August. Females give birth to a single calf once every three years, on average. After about three months, the mother-calf pairs set off for the South Atlantic to feed for the remainder of the year. They feed on krill and other crustaceans.

The study combined two techniques that revealed the relationships between whales as well as an indication of where the whales were feeding, relative to one another.

The first technique involved the analysis of the whales’ maternal DNA. This enabled scientists to establish how the whales were related to one another. The second technique analyzed small skin samples from the whales to determine where the whales were feeding. This technique relies on the fact that the different chemical isotopes are deposited in the whale’s skin depending on the location of its feeding ground. This means that although scientists know very little about the exact location of southern right whale feeding grounds, they can still establish which individuals are feeding in the same location since those individuals will exhibit similarities in their skin chemistry.

The pairing of these two techniques was a new approach for the team--never before had they used genetic analysis and chemical isotope analysis together to characterize whale biology and behavior.

The study authors included Victoria Rowntree, Jon Segar, and Luciano Valenzuela from the University of Utah as well as Mariano Sironi, scientific director of the Institute for the Conservation of Whales in Argentina.

The results of this research sheds light on the possible vulnerability southern right whales have to climate change. Victoria Rowntree explains:

The influence of climate change on southern right whales is not new territory for Rowntree. In a paper published in 2006, Rowntree and her colleages establish a strong correlation between sea surface temperatures in the southwest Atlantic and breeding success in southern right whale populations. That researched showed that if sea surface temperatures are elevated in during the fall, the southern right whales experienced reduced breeding success the in following season.

• Mama Whales Teach Babies Where to Eat (Eurekalert)
• Leaper R, Cooke J, Trathan P, Reid K, Rowntree V, Payne R. 2006. Global Climate Drives Southern Right Whale Population Dynamics. Biology Letters. Vol 2(2) pp 289-292.

Photo (top) © John Atkinson / Ocean Alliance. For a month after birth, Southern right whale mothers and their calves rest and nurse before embarking on a long migration in the South Atlantic to reach their feeding grounds.

Photo (bottom) © John Atkinson / Ocean Alliance. A mother and calf pair of southern right whales swims in waters off Argentina’s Peninsula Valdes.

The decline in amphibian populations around the world has caused much concern among biologists and conservationists during recent years. Yet to this point, most of the data documenting amphibian declines has focused on frog populations. Now, a new study offers evidence of salamander population declines as well.

A team of biologists from the University of California, Berkeley compared recent salamander population data to population data collected between 1969 and 1978. The results of the comparison indicated a similar sharp decline in salamander populations as has been observed in frog populations.

Salamanders lead a more secretive life than many species of frogs do, so detecting a decline in salamander numbers can be more difficult and their disappearance are often less visible.

The study revealed that at one site located on the Tajumulco volcano along the west coast of Guatemala, the three most common species that were present 40 years ago had suffered alarming declines. Two of the three species have disappeared completely and the third was very difficult to locate.

"There have been hints before—people went places and couldn't find salamanders. But this is the first time we've really had, with a very solid, large database, this kind of evidence," ~ study leader David Wake, professor of integrative biology at UC Berkeley and curator of herpetology in the campus's Museum of Vertebrate Zoology.

The decline in frog populations has been shown to be the result of multiple factors such as habitat destruction, climate change, pollution, disease, and over-exploitation. But this study sheds light on a single prominent cause behind salamander declines: climate change. Since many of the salamanders studied inhabit narrow elevation bands, they are especially susceptible to temperature fluctuations, which may drive them to higher elevations and less suitable habitats.

• Scientists Document Salamander Decline in Central America (Eurekalert)

Photo © Sean M. Rovito / UC Berkeley. The terrestrial salamander Pseudoeurycea goebeli, once common to the cloud forests of the Tajumulco volcano.

Researchers from the University of Calgary have revealed that the caribou (Rangifer tarandus) that inhabit Canada's southern Rocky Mountains are unique blend of two distinct caribou lineages. Their work suggests that after the last ice age ended about 10,000 years ago, the receding glaciers left an open corridor that enabled once-isolated populations of caribou to intermix.

It is thought that barren-ground caribou (Rangifer tarandus groenlandicus) migrated southward via this ice-free channel until their range overlapped with the more southerly breed of caribou, the woodland caribou (Rangifer tarandus caribou). The two lineages interbred and this genetic 'mixing' produced the mountain caribou of Canada's southern Rocky Mountains.

The discovery of this unique breed of caribou highlights the need for the careful management and conservation of the various caribou subspecies and populations. At present, there are four subspecies of caribou:

• Woodland caribou (Rangifer tarandus caribou)
• Barren-ground caribou (Rangifer tarandus groenlandicus)
• Peary caribou (Rangifer tarandus pearyi)
• Svalbard reindeer (Rangifer tarandus platyrhynchus)

McDevitt A, Mariani S, et. al. 2009. Survival in the Rockies of an Endangered Hybrid Swarm From Diverged Caribou (Rangifer tarandus) Lineages. Molecular Ecology. Vol 18(4). pp. 665-679.

Photo © Mark Bradley / Boreal Nature Photos.

A fossilized turtle unearthed by geologists working in the Canadian Arctic has shed new light on what the Arctic Ocean was like during the late Cretaceous period, some 90 million years ago. The fossil, named Aurorachelys (or 'aurora turtle'), is believed to be a tropical, freshwater species that originated in Asia.

Auroracheyles presented scientists with a puzzle. Here was a tropical species in a polar region, a freshwater turtle in marine habitat, and an Asian turtle in North America. How did Auroracheyles end up in the Canadian Arctic and how did it survive?

The scientific team that made the discovery was lead by John Tarduno of the University of Rochester. His team suggests that during the time Auroracheyles lived, there may have been a freshwater sea floating atop the marine Arctic Ocean. Additionally, they suggest that a series of volcanic events may have produced a chain of islands that may have facilitated migration of species from Russia to Canada.

Tarduno and his colleagues also believe the Arctic was warmer during the time Aurorachelys lived. A 'super-greenhouse' effect, thought to have occurred 90 million years ago, could have generated enough polar heat to enable the tropical species to thrive.

"We've known there's been an interchange of animals between Asia and North America in the late Cretaceous period, but this is the first example we have of a fossil in the High Arctic region showing how this migration may have taken place," ~John Tarduno, professor of geophysics at the University of Rochester and leader of the expedition.

Ancient Turtle Migrated from Asia to America Over a Tropical Arctic (University of Rochester)

Photo (top) © University of Rochester. Fossil of Asian, tropical, freshwater turtle found in Arctic Canada.

Photo (bottom) © University of Rochester. Arctic region where turtle fossil was found.

Recent molecular studies have revealed that Zosteropidae—a family of birds commonly referred to as white-eyes—diversify into new species faster than any other group of birds. Scientists estimate that every one million years, between 2.24 and 3.16 new species of white eye appears. The Zosteropidae family presently includes more than 100 species and the family is estimated to be between 4.46 and 5.57 million years old.

White-eyes are so named for the white ring of feathers that encircles their eyes. The range of the white eye family extends from from Asia to Africa and into Oceania.

White-eyes' tendency for rapid diversification first caught the attention of evolutionary biologists Ernst Mayr and Jared Diamond nearly 80 years ago when they visited the Solomon Islands. Mayr and Diamond observed that within geographical regions where other birds showed little or no diversification, white-eyes were highly varied. Mayr and Diamond went on to suggest that white eyes may possess a set of inherent traits that made them 'great speciators'. Until recently, there was no way to test their hypothesis.

But with the advent of molecular genetics, the mechanism of speciation in white-eyes could be explored in greater detail than ever before. A team of experts banded together to delve deeper into the mysteries of white eye speciation—the team included Christopher Filardi (Biodiversity Scientist for the Pacific Programs at the Center for Biodiversity and Conservation at the American Museum of Natural History), Rob Moyle (University of Kansas), Catherine Smith (Missoula, Montana), and Jared Diamond (University of California at Los Angeles).

That Jared Diamond was able to participate in this research was particularly significant—it enabled him to answer questions he had posed with Mayr nearly eight decades earlier:

The molecular evidence gathered by the team supports the 'great speciator' hypothesis proposed by Mayr and Diamond and suggests that there are indeed some inherent traits enabling white eyes to rapidly form new species. Such traits might include the ability of the species to survive in a wide variety of habitats, and the short time between generations when compared to other groups of birds.

• White-eyes Diversity Across a Hemispheric Range Faster than any Other Bird (American Museum of Natural History)
• ‘Great speciators’ explained: It’s intrinsic (Eurekalert)

Photo © C. Filardi / CBC-AMNH. The splendid white-eye (Zosterops splendidus) is found only on the tiny island of Ranongga is one of seven species endemic to islands of the New Georgia Group, Solomon Islands.

In this issue of Wildlife News Roundup, we find out about a jellyfish that, when stressed, reverts to an earlier stage in its life cycle. We also learn of an underlying trigger for locusts to switch from a solitary to swarming lifestyle. There's news of a brewing argument between the Nature Conservancy and the Department of Homeland Security. There is also reports of a rise in the mountain gorilla population in Virunga National Park and a sharp decline in the northern rockhopper penguin population.

• Rising Acidity Is Threatening Food Web of Oceans (New York Times) — January 30, 2009. Our planet's oceans are natural buffers for climate. They absorb a significant amount of carbon dioxide from the atmosphere and in doing so help to temper global warming. But the carbon dioxide absorbed by our oceans raises the acidity of the water and that means coral reefs, shellfish, and marine food webs are at risk.
• 'Immortal' Jellyfish Swarm World's Oceans (National Geographic) — January 29, 2009. When the tiny jellyfish, Turritopsis dohrnii, encounters stresses such as lack of food or physical damage, it reverses its life cycle and transforms back into a polyp colony.
• Locust Swarms Switched On by Brain Chemical (National Geographic) — January 29, 2009. Locusts live a dichotomous lifestyle, alternating between solitary individuals and swarming masses. Now scientists believe they have found the mechanism that turns on and off the two very different lifestyles of the locust.
• Mountain Gorilla Population Increases Despite War (WWF) — January 27, 2009. The WWF reports that the mountain gorilla population in Virunga National Park has risen despite war in the region. The gorilla numbers rose from 72 individuals in 2007 to 81 at present.
• Nature Conservancy Fights Planned Border Fence (NPR) — January 26, 2009. The Department of Homeland Security intends to erect a border fence made of concrete and barrier, 18-feet high, inside the boundaries of the Nature Conservancy's Lennox Foundation Southmost Preserve. The Nature Conservancy is fighting the action and has turned down $114,000 in mitigation moneys from the government.
• Growing Taste for Reef Fish Sends Their Numbers Sinking (New York Times) — January 19, 2009. Demand for reef fish at restaurants in Southeast Asia and mainland China is having a severe impact on the fish populations in the Coral Triangle, a protected marine region home to the world’s richest ocean diversity.
• Penguins Are Walking an Increasingly Rocky Road (BirdLife International) — January 16, 2009. The northern rockhopper penguin population has plummetted 90 precent over the last five decades according to BirdLife International. The northern rockhopper penguins inhabit primarily UK territories throughout the South Atlantic and as a result British conservationists are looking to the UK Government to provide resources to protect the threatened birds.
• Mystery Ailment Killing Endangered Pelicans (NPR) — January 16, 2009. Scientists have found that an unknown illness is spreading through populations of California brown pelicans. Sick birds grow thin, dehydrated and disoriented. As of yet, no cause has been determined.
• Ten Extinct Beasts That Could Walk the Earth Again (New Scientist) — January 7, 2009. The deciphering of the DNA sequence of the extinct woolly mammoth prompted science writer Henry Nicholls to speculate about the animals scientists might someday be able to bring back to life.
• Move Over, Polar Bear (New Scientist) — January 7, 2009. The polar bear is not alone in its vulnerability to climate change. There are thousands of species that inhabit the planet's tropical rainforests that face equal peril in as temperatures rise.

About Wildlife News Roundup

Wildlife News Roundup is a monthly digest featuring animals and wildlife headlines from around the web. It includes headlines from well-established sources such as the World Wildlife Fund, BBC News, New York Times, National Public Radio, National Geographic, and Birdlife International. The sources are selected with care and include only those that archive articles for many years, offer top-notch science writing, and follow stories as they develop over time.

Photo © Fotoron / iStockphoto. Northern rockhopper penguin.

A population study of Asian elephants (Elephas maximus) living in Taman Negara National Park, Malaysia, has revealed that there may be as many as 631 of the endangered elephants in the park—making it the largest known population of the endangered elephants in Southeast Asia. The current range of Asian elephants includes India, Southeast Asia, Sumatra and Borneo. Their former range also included areas south of the Himalayas and China, north to the Yangtze River. Unfortuantely, the species has suffered greatly at the hands of habitat destruction and poaching. Today as few as 30,000 to 50,000 individuals remain in 13 Asian countries.

The Taman Negara National Park elephant population study was conducted by scientists from the Wildlife Conservation Society and Malaysia's Department of Wildlife and National Parks. To estimate elephant numbers, the researchers counted the number of dung piles left behind by the elephants. What such a task lacks in glamour it makes up for in reliability—it turns out that dung piles provide a very reliable means of estimating the number of elephant that are present in an area.

The results of the survey highlight the importance of the Taman Negara National Park in protecting the rare elephants:

Taman Negara National Park is a 4,343 square kilometer protected area located in the heart of the Malay Peninsula. The park was established in 1938 and encompasses pristine lowland evergreen rainforest habitats within three Malaysian states: Kelantan, Terengganu, and Pahang.

Jumbo-Sized Discovery Made in Malaysia (Newswise)

Photo © Simon Hedges / Wildlife Conservation Society.