New Animal And Plant Species Found In Vietnam

Source:

http://www.sciencedaily.com/releases/2007/09/070925204929.htm

Science Daily — World Wildlife Fund scientists have just announced the discovery of 11 new animal and plant species in a remote area in central Vietnam. They say this underscores the importance of conservation efforts in the ancient tropical forests of the region.

Within the ancient tropical forests of a region known as Vietnam's "Green Corridor," scientists found a snake, five orchids, and two butterflies as well as three other plants new to science and exclusive to the Annamites Mountain Range. Ten other plant species, including four orchids, are still under examination but also appear to be new species.
"Discoveries of so many new species are rare and occur only in very special places like the Green Corridor," said Dr. Chris Dickinson, WWF's chief conservation scientist in the Green Corridor. "Several large mammal species were discovered in the 1990s in the same forests so these latest discoveries may be just the tip of the iceberg."
The rainforests of the Central Annamites likely existed as continuous undisturbed forest cover for thousands of years, and, as a result, offer unique habitats for many species, said WWF experts.
The new snake species, called the white-lipped keelback, prefers living by streams where it catches frogs and other small animals. With a beautiful yellow-white stripe sweeping along its head and red dots covering its body, the white-lipped keelback can reach 31 inches--almost a yard in length.
Three of the new orchid species are entirely leafless, a rarity even among orchids. Containing none of the chlorophyll or green pigment commonly found in plants, these orchids live on decaying matter like many fungal species. The other new plants include an aspidistra which produces a nearly black flower and a newly-discovered species of arum with beautiful yellow flowers. Arum plants have funnel-shaped leaves surrounding the flowers.
The two new butterfly species are among eight discovered in the province since 1996. One is a skipper -- a butterfly with quick, darting flight habits--from the genus Zela and the other is a new genus in the subfamily of Satyrinae.
According to WWF experts, all of these species are at risk from illegal logging, hunting, unsustainable extraction of natural resources and conflicting development interests. However, local authorities -- in particular the Thua Thien Hue Provincial Forest Protection Department -- have committed to conserve and sustainably manage these valuable forests.
"The area is extremely important for conservation and the province wants to protect the forests and their environmental services, as well as contribute to sustainable development," said Hoang Ngoc Khanh, director of Thua Thien Hue Provincial Forest Protection Department.
Stretching from the mountainous forests of the Annamites to one of the last remaining lowland wet evergreen forests, the Green Corridor supports significant populations of threatened species and includes some of the longest remaining stretches of lowland river with intact forest habitat in Vietnam feeding into the Perfume River.
Recent surveys found 15 reptiles and amphibians and six bird species among the threatened species living there. It is also home to one of the world's most endangered primates--white-cheeked crested gibbons--and the best location in Vietnam to save the saola--a unique type of wild cattle just discovered by scientists in 1992.
According to WWF experts, the forests of the Annamites are important water catchments, supplying water for thousands of people who depend on the region's rivers. Local ethnic minority groups earn more than half of their income from the non-timber resources of these same forests. Note: This story has been adapted from a news release issued by World Wildlife Fund.

Fausto Intilla

www.oloscience.com

Extinction Crisis Escalates: Red List Shows Apes, Corals, Vultures, Dolphins All In Danger

Source:

http://www.sciencedaily.com/releases/2007/09/070912152659.htm

Science Daily — Life on Earth is disappearing fast and will continue to do so unless urgent action is taken, according to the 2007 IUCN Red List of Threatened Species.

There are now 41,415 species on the IUCN Red List and 16,306 of them are threatened with extinction, up from 16,118 last year. The total number of extinct species has reached 785 and a further 65 are only found in captivity or in cultivation.
One in four mammals, one in eight birds, one third of all amphibians and 70% of the world’s assessed plants on the 2007 IUCN Red List are in jeopardy.
Julia Marton-Lefèvre, Director General of the World Conservation Union (IUCN), said: “This year’s IUCN Red List shows that the invaluable efforts made so far to protect species are not enough. The rate of biodiversity loss is increasing and we need to act now to significantly reduce it and stave off this global extinction crisis. This can be done, but only with a concerted effort by all levels of society.”
The IUCN Red List of Threatened Species is widely recognized as the most reliable evaluation of the world’s species. It classifies them according to their extinction risk and brings into sharp focus the ongoing decline of the world’s biodiversity and the impact that mankind is having upon life on Earth.
Jane Smart, Head of IUCN’s Species Programme, said: “We need to know the precise status of species in order to take the appropriate action. The IUCN Red List does this by measuring the overall status of biodiversity, the rate at which it is being lost and the causes of decline.
“Our lives are inextricably linked with biodiversity and ultimately its protection is essential for our very survival. As the world begins to respond to the current crisis of biodiversity loss, the information from the IUCN Red List is needed to design and implement effective conservation strategies – for the benefit of people and nature.”
Some highlights from this year’s IUCN Red List
Decline of the great apes
A reassessment of our closest relatives, the great apes, has revealed a grim picture. The Western Gorilla (Gorilla gorilla) has moved from Endangered to Critically Endangered, after the discovery that the main subspecies, the Western Lowland Gorilla (Gorilla gorilla gorilla), has been decimated by the commercial bushmeat trade and the Ebola virus. Their population has declined by more than 60% over the last 20-25 years, with about one third of the total population found in protected areas killed by the Ebola virus over the last 15 years.
The Sumatran Orangutan (Pongo abelii) remains in the Critically Endangered category and the Bornean Orangutan (Pongo pygmaeus) in the Endangered category. Both are threatened by habitat loss due to illegal and legal logging and forest clearance for palm oil plantations. In Borneo, the area planted with oil palms increased from 2,000 km2 to 27,000 km2 between 1984 and 2003, leaving just 86,000 km2 of habitat available to the species throughout the island.
First appearance of corals on the IUCN Red List
Corals have been assessed and added to the IUCN Red List for the very first time. Ten Galápagos species have entered the list, with two in the Critically Endangered category and one in the Vulnerable category. Wellington’s Solitary Coral (Rhizopsammia wellingtoni) has been listed as Critically Endangered (Possibly Extinct). The main threats to these species are the effects of El Niño and climate change.
In addition, 74 seaweeds have been added to the IUCN Red List from the Galápagos Islands. Ten species are listed as Critically Endangered, with six of those highlighted as Possibly Extinct. The cold water species are threatened by climate change and the rise in sea temperature that characterizes El Niño. The seaweeds are also indirectly affected by overfishing, which removes predators from the food chain, resulting in an increase of sea urchins and other herbivores that overgraze these algae.
Yangtze River Dolphin listed as Critically Endangered (Possibly Extinct)
After an intensive, but fruitless, search for the Yangtze River Dolphin, or Baiji, (Lipotes vexillifer) last November and December, it has been listed as Critically Endangered (Possibly Extinct). The dolphin has not been placed in a higher category as further surveys are needed before it can be definitively classified as Extinct. A possible sighting reported in late August 2007 is currently being investigated by Chinese scientists. The main threats to the species include fishing, river traffic, pollution and degradation of habitat.
India and Nepal’s crocodile, the Gharial (Gavialis gangeticus) is also facing threats from habitat degradation and has moved from Endangered to Critically Endangered. Its population has recently declined by 58%, from 436 breeding adults in 1997 to just 182 in 2006. Dams, irrigation projects, sand mining and artificial embankments have all encroached on its habitat, reducing its domain to 2% of its former range.
Vulture crisis
This year the total number of birds on the IUCN Red List is 9,956 with 1,217 listed as threatened. Vultures in Africa and Asia have declined, with five species reclassified on the IUCN Red List. In Asia, the Red-headed Vulture (Sarcogyps calvus) moved from Near Threatened to Critically Endangered while the Egyptian Vulture (Neophron percnopterus) moved from Least Concern to Endangered. The rapid decline in the birds over the last eight years has been driven by the drug diclofenac, used to treat livestock.
In Africa, three species of vulture have been reclassified, including the White-headed Vulture (Trigonoceps occipitalis), which moved from Least Concern to Vulnerable, the White-backed Vulture (Gyps africanus) and Rüppell’s Griffon (Gyps rueppellii), both moved from Least Concern to Near Threatened. The birds’ decline has been due to a lack of food, with a reduction in wild grazing mammals, habitat loss and collision with power lines. They have also been poisoned by carcasses deliberately laced with insecticide. The bait is intended to kill livestock predators, such as hyenas, jackals and big cats, but it also kills vultures.
North American reptiles added
After a major assessment of Mexican and North American reptiles, 723 were added to the IUCN Red List, taking the total to 738 reptiles listed for this region. Of these, 90 are threatened with extinction. Two Mexican freshwater turtles, the Cuatro Cienegas Slider (Trachemys taylori) and the Ornate Slider (Trachemys ornata), are listed as Endangered and Vulnerable respectively. Both face threats from habitat loss. Mexico’s Santa Catalina Island Rattlesnake (Crotalus catalinensis) has also been added to the list as Critically Endangered, after being persecuted by illegal collectors.
Plants in peril
There are now 12,043 plants on the IUCN Red List, with 8,447 listed as threatened. The Woolly-stalked Begonia (Begonia eiromischa) is the only species to have been declared extinct this year. This Malaysian herb is only known from collections made in 1886 and 1898 on Penang Island. Extensive searches of nearby forests have failed to reveal any specimens in the last 100 years.
The Wild Apricot (Armeniaca vulgaris), from central Asia, has been assessed and added to the IUCN Red List for the first time, classified as Endangered. The species is a direct ancestor of plants that are widely cultivated in many countries around the world, but its population is dwindling as it loses habitat to tourist developments and is exploited for wood, food and genetic material.
Banggai Cardinalfish heavily exploited by aquarium trade
Overfishing continues to put pressure on many fish species, as does demand from the aquarium trade. The Banggai Cardinalfish (Pterapogon kauderni), which is highly prized in the aquarium industry, is entering the IUCN Red List for the first time in the Endangered category. The fish, which is only found in the Banggai Archipelago, near Sulawesi, Indonesia, has been heavily exploited, with approximately 900,000 extracted every year. Conservationists are calling for the fish to be reared in captivity for the aquarium trade, so the wild populations can be left to recover.
These highlights from the 2007 IUCN Red List are merely a few examples of the rapid rate of biodiversity loss around the world. The disappearance of species has a direct impact on people’s lives. Declining numbers of freshwater fish, for example, deprive rural poor communities not only of their major source of food, but of their livelihoods as well.
Species loss is our loss
Conservation action is slowing down biodiversity loss in some cases, but there are still many species that need more attention from conservationists. This year, only one species has moved to a lower category of threat. The Mauritius Echo Parakeet (Psittacula eques), which was one of the world’s rarest parrots 15 years ago, has moved from Critically Endangered to Endangered. The improvement is a result of successful conservation action, including close monitoring of nesting sites and supplementary feeding combined with a captive breeding and release programme.
Background information
The IUCN Red List of Threatened Species classifies species according to their extinction risk. It is a searchable online database containing the global status and supporting information on more than 41,000 species. Its primary goal is to identify and document the species most in need of conservation attention and provide an index of the state of biodiversity.
The IUCN Red List threat categories are the following, in descending order of threat:
Extinct or Extinct in the Wild;
Critically Endangered, Endangered and Vulnerable: species threatened with global extinction;
Near Threatened: species close to the threatened thresholds or that would be threatened without ongoing specific conservation measures;
Least Concern: species evaluated with a low risk of extinction;
Data Deficient: no evaluation because of insufficient data.
Critically Endangered (Possibly Extinct): This is not a new Red List category, but is a flag developed to identify those Critically Endangered species that are in all probability already Extinct but for which confirmation is required (for example, through more extensive surveys being carried out and failing to find any individuals).
The total number of species on the planet is unknown; estimates vary between 10 - 100 million, with 15 million species being the most widely accepted figure. 1.7 - 1.8 million species are known today.
People, either directly or indirectly, are the main reason for most species’ decline. Habitat destruction and degradation continues to be the main cause of species’ decline, along with the all too familiar threats of introduced invasive species, unsustainable harvesting, over-hunting, pollution and disease. Climate change is increasingly recognized as a serious threat, which can magnify these dangers.
Major analyses of the IUCN Red List are produced every four years. These were produced in 1996, 2000 and 2004.
Key findings from major analyses to date include:
The number of threatened species is increasing across almost all the major taxonomic groups.
IUCN Red List Indices, a new tool for measuring trends in extinction risk are important for monitoring progress towards the 2010 target. They are available for birds and amphibians and show that their status has declined steadily since the 1980s. An IUCN Red List Index can be calculated for any group which has been assessed at least twice.
Most threatened birds, mammals and amphibians are located on the tropical continents – the regions that contain the tropical broadleaf forests which are believed to harbour the majority of the Earth’s terrestrial and freshwater species.
Of the countries assessed, Australia, Brazil, China and Mexico hold particularly large numbers of threatened species.
Estimates vary greatly, but current extinction rates are at least 100-1,000 times higher than natural background rates.
The vast majority of extinctions since 1500 AD have occurred on oceanic islands, but over the last 20 years, continental extinctions have become as common as island extinctions.
Note: This story has been adapted from a news release issued by World Conservation Union.

Fausto Intilla

www.oloscience.com

Enormous Spider Web Found In Texas

Source:

http://www.sciencedaily.com/releases/2007/09/070912145919.htm

Science Daily — An arachnaphobe’s worst nightmare, the gauzy, insect-laden web drew more than 3,300 curious visitors over the three-day holiday to this 376-acre park on the shore of Lake Tawakoni, 50 miles east of Dallas. On Labor Day, the park recorded 1,275 people visiting just to see the web.

“When I first saw it,” said Park Superintendent Donna Garde, “I was totally amazed. What ran through my mind was that this looked like something out of a low-budget horror movie, but I was looking at something five times as big as what you’d see on a Hollywood set.”
Stumped as to the web’s origin, the initial consensus of arachnologists and entomologists who saw an online photo of the web sent by Texas Parks and Wildlife Department biologist Mike Quinn was that it may have resulted from a “mass dispersal” event. In such an event, millions of tiny spiders or spiderlings spin out silk filaments to ride air currents in a phenomenon known as “ballooning.”
Quinn collected a sample of spiders Aug. 31 from in and around the gigantic web and took them to Texas A&M University in College Station for analyses. Entomology Department researcher Allen Dean identified 11 spider families from the sample. The most prevalent species was the Tetragnatha guatemalensis, or what Quinn dubbed the Guatemalan long-jawed spider, since this species didn’t have a common name. Guatemala was the country in which it was first documented.
“I drove 50 to 100 spiders to A&M on Saturday,” Quinn said. “Spider experts tend to specialize in one or few families of spiders. There are nearly 900 species of spiders known from Texas, so no one is an expert on all the species.”
Quinn described the Lake Tawakoni web as “sheet webbing” since it covers a large area of trees, which is more typical of a web spun by a funnel web spider rather than the classic Charlotte’s web, or orb web, like that produced by long-jawed spiders. He speculates that the park’s spider population exploded due to wet conditions this summer that resulted in an abundance of midges and other a small insects upon which the spiders feed.
The Guatemalan long-jawed spider ranges from Canada to Panama, and even the islands of the Caribbean. According to Quinn, the spider is about an inch in length with a reddish-orange head- and-thorax. Spiders, like mites and scorpions, are arachnids, a group of arthropods with four pairs of legs, saclike lungs and a body divided into two segments.
So popular was the monster Lake Tawakoni spider web phenomenon that it ran as the lead story in the Nation section of the Aug. 31 New York Times, and was the newspaper’s most e-mailed article that day. The nightmarish quality of the story prompted satirical takes on several Internet Web sites and led to national coverage on Fox News, the Discovery Channel, CNN and other networks. Quinn termed the degree of news coverage “remarkable.”
Dr. Norman Horner, a retired dean of the College of Science and Mathematics at Midwestern State University in Wichita Falls, was on his way to the park mid-week to study the “not very common” phenomenon, when he received a call from park staff telling him that a heavy overnight rainstorm had made the trail impassable and knocked down much of the giant web.
“So far,” Horner said, “we have been informed of webs of this nature occurring in Florida, California, Canada, Italy, Ohio and now Texas. In all cases, they appear to have been produced by tetragnathids, but have other species associated with them.”
Superintendent Garde said Sept. 5 that the crowds coming to see the wondrous creation had slowed to a trickle, and that they were not being allowed to access the nature trail due to the sloppy conditions.
“It was fun, but we were really tired,” Garde said. “The spiders are great little guys. They put our park on the map.”
Note: This story has been adapted from a news release issued by Texas A & M University.

Fausto Intilla

www.oloscience.com

Corals Added To IUCN Red List Of Threatened Species For First Time

Source:

http://www.sciencedaily.com/releases/2007/09/070912094029.htm

Science Daily — For the first time in history, the IUCN Red List of Threatened Species includes ocean corals in its annual report of wildlife going extinct.

A comprehensive study of marine life sponsored by Conservation International (CI) and implemented jointly with the IUCN (World Conservation Union) used data from the Galapagos-based Charles Darwin Research Station and other regional institutions to conclude that three species of corals unique to the Galapagos Islands could soon disappear forever.
The 2007 IUCN Red List designates two of the corals -- Floreana coral (Tubastraea floreana) and Wellington's solitary coral (Rhizopsammia wellingtoni) -- as Critically Endangered, while a third -- Polycyathus isabela -- is listed as Vulnerable. The Red List also includes 74 Galapagos seaweeds, or macro-algae, with 10 of them receiving the most threatened status of Critically Endangered. Prior to 2007, only one algae species had been included on the Red List.
"There is a common misconception that marine species are not as vulnerable to extinction as land-based species," said Roger McManus, CI's vice president for marine programs. "However, we increasingly realize that marine biodiversity is also faced with serious environmental threat, and that there is an urgent need to determine the worldwide extent of these pressures to guide marine conservation practice."
The Galapagos marine research was conducted by the Global Marine Species Assessment (GMSA), a joint initiative of IUCN and CI launched in 2005 with the support of dozens of experts and research institutions. The GMSA is studying a large portion of Earth's marine species to determine the threat of extinction.
"These Galapagos corals and algae are the first of many marine species that will be added to the Red List due to our findings," said GMSA Director Kent Carpenter of Old Dominion University in Virginia. "What is significant is that climate change and over-fishing -- two of the biggest threats to marine life -- are the likely causes in these cases."
Scientists blame climate change for more frequent and increasingly severe El Niño events that have caused dramatic rises in water temperatures and reduced nutrient availability around the Galapagos Islands in the Eastern Tropical Pacific Ocean, off South America. The warmer water harms corals and algae, both of which constitute the structural foundation of unique and diverse marine ecosystems.
Corals build reefs that are habitat for fish and other marine life, and also are a major attraction for divers in the Galapagos, where tourism makes a significant contribution to the local and national economy.
The recovery of algae species following strong El Niño events is harmed by over-fishing of the natural predators of sea urchins, which feed on the algae. Mushrooming urchin populations scour rocks clean of algae, depleting a major food source for other species such as the Galapagos marine iguana.
"Marine ecosystems are vulnerable to threats at all scales -- globally through climate change, regionally from El Niño events, and locally when over-fishing removes key ecosystem building blocks," said Jane Smart, head of the IUCN Species Program. "We need more effective solutions to manage marine resources in a more sustainable way in light of these increasing threats."
Other coral and algae species lacked sufficient information to determine their IUCN Red List status, so they received the designation of Data Deficient. Researchers believe many of these species are likely to be listed as threatened with extinction when more detailed information becomes available.
The GMSA is the first strategic global review of the conservation status of marine species, including every marine vertebrate species and selected invertebrates and plants. Funded predominantly by CI, the five-year GMSA initiative is engaging experts from around the world to compile and analyze all existing information on the status of approximately 20,000 marine species to determine their risk of extinction according to the IUCN Red List Categories and Criteria. The resulting analysis will identify marine "hotspots" of high conservation priority in order to focus protection efforts on their habitats and species.
Note: This story has been adapted from a news release issued by Conservation International.

Fausto Intilla

www.oloscience.com

Primates Expect Others To Act Rationally

Source:

http://www.sciencedaily.com/releases/2007/09/070906140753.htm

Science Daily — When trying to understand someone's intentions, non-human primates expect others to act rationally by performing the most appropriate action allowed by the environment, according to a new study by researchers at Harvard University.

The work was led by Justin Wood, a graduate student in the Department of Psychology in the Faculty of Arts and Sciences at Harvard, with David Glynn, a research assistant, and Marc Hauser, professor of psychology at Harvard, along with Brenda Phillips of Boston University.
"A dominant view has been that non-human primates attend only to what actions 'look like' when trying to understand what others are thinking," says Wood. "In contrast, our research shows that non-human primates infer others' intentions in a much more sophisticated way. They expect other individuals to perform the most rational action that they can, given the environmental obstacles that they face."
The scientists studied the behavioral response of over 120 primates, including cotton-top tamarins, rhesus macaques and chimpanzees. These species represent each of the three major groups of primates: New World monkeys, Old World monkeys and apes. All three species were tested in the same way, and the results showed the same responses among the different types.
In the first experiment, the primates were presented with two potential food containers, and the experimenter either purposefully grasped one of the containers, or flopped their hand onto one of the containers in an accidental manner. For all three species, the primates sought the food container that was purposefully grasped a greater number of times than the container upon which the hand was flopped. This indicates that the primate inferred goal-oriented action on the part of the experimenter when he grasped the container, and was able to understand the difference between the goal-oriented and accidental behavior.
In the second experiment, the researchers asked if the primates infer others' goals under the expectation that other individuals will perform the most rational action allowed by the environmental obstacles. Again, the primates were presented with two potential food containers. In one scenario, an experimenter touched a container with his elbow when his hands were full, and in another scenario, touched a container with his elbow when his hands were empty.
The primates looked for the food in the container indicated with the elbow more often when the experimenter's hands were full. The primates considered, just as a human being would, that if someone's hands are full then it is rational for them to use their elbow to indicate the container with food, whereas if their hands are empty it is not rational for them to use their elbow, because they could have used their unoccupied hand.
Developmental psychologists have long understood that young children are able to engage in this type of rational action perception, but scientists have not understood if this ability is unique to human beings, or shared with other animals. This study suggests that this ability evolved as long as 40 million years ago, with non-human primates.
"This study represents one of the broadest comparative studies of primate cognition, and the significance of the findings is reinforced by the fact that these results were consistent across three different species of primates," says Wood. "The results have significant implications for understanding the evolution of the processes that allow us to make sense of other people's behavior."
The findings appear in the Sept. 7 issue of the journal of Science.
The research was funded by the National Institutes of Health, the Guggenheim, and the National Science Federation.
Note: This story has been adapted from a news release issued by Harvard University.

Fausto Intilla

www.oloscience.com

PCBs May Threaten Killer Whale Populations For 30-60 Years

Source:

http://www.sciencedaily.com/releases/2007/09/070910094122.htm

Science Daily — Orcas or killer whales may continue to suffer the effects of contamination with polychlorinated biphenyls (PCBs) for the next 30 -- 60 years, despite 1970s-era regulations that have reduced overall PCB concentrations in the environment, researchers in Canada report. The study calls for better standards to protect these rare marine mammals.

In the study, Brendan Hickie and Peter S. Ross and colleagues point out that orcas face a daunting array of threats to survival, including ship traffic, reduced abundance of prey and environmental contamination. Orcas, which reach a length exceeding 25 feet and weights of 4-5 tons, already are the most PCB-contaminated creatures on Earth. Scientists are trying to determine how current declines in PCBs in the environment may affect orcas throughout an exceptionally long life expectancy, which ranges up to 90 years for females and 50 years for males.
The new study used mathematical models and measurements of PCBs in salmon (orcas' favorite food) and ocean floor cores to recreate a PCB exposure history to estimate PCB concentrations in killer whales over time. It concluded that the "threatened" northern population of 230 animals will likely face health risks until at least 2030, while the endangered southern population of 85 orcas may face such risks until at least 2063. PCBs make whales more vulnerable to infectious disease, impair reproduction, and impede normal growth and development, the researchers say.
"The findings provide conservationists, regulators, and managers with benchmarks against which the effectiveness of mitigative steps can be measured and tissue residue guidelines can be evaluated," the study reported. "The results of our study on PCBs may paint an ominous picture for risks associated with emerging chemicals, as the concentrations of structurally-related PBDEs are doubling every 4 years in marine mammals," researchers added.
"Killer Whales (Orcinus orca) Face Protracted Health Risks Associated with Lifetime Exposure to PCBs" Environmental Science & Technology, September 15, 2007
Note: This story has been adapted from a news release issued by American Chemical Society.

Fausto Intilla

www.oloscience.com

Ecologists Get To The Bottom Of Why Bears Rub Trees

Source:

http://www.sciencedaily.com/releases/2007/09/070909221303.htm

Science Daily — Ecologists have at last got to the bottom of why bears rub trees – and it's not because they have itchy backs. Speaking at the British Ecological Society's Annual Meeting in Glasgow the week of September 10, Dr Owen Nevin of the University of Cumbria will reveal that adult male grizzly bears use so-called “rub trees” as a way to communicate with each other while looking for breeding females, and that this behaviour could help reduce battles between the bears.

Many theories have been advanced as to why bears rub trees: some thought females might rub trees as they came into oestrous, and others that bears might be giving their backs a good scratch to get rid of parasites or pick up sap to act as insect repellent. Until now these ideas have been extremely difficult to test because bears usually live at low densities and rubbing is relatively rare behaviour.
Because bears use the same rub trees for generations, and because he has logged rub trees over almost a decade working on bears in British Columbia in Canada, Nevin has been able to gain a unique insight into grizzlies' behaviour. Over the past two years, he used four digital cameras with infra-red trips set up opposite rub trees to collect data on which bears used the trees and when. He coupled this with satellite telemetry equipment to track individual bears' movements.
“The cameras show that adult male bears are the most likely to rub trees, and the satellite telemetry tells us that males move from valley to valley in large loops, marking trees as they go, while looking for breeding females,” Nevin says.
Nevin believes that by marking trees, adult males may be getting to know each other better, and that this scent familiarity could act as a way of reducing fighting among adult male bears. According to Nevin: “Big male bears can seriously injure and even kill each other when they get into a fight. If one recognises the other from the scent marks on the rub trees in the area he knows he’s in for a tough fight - he’s on the other guy’s patch so to speak - so it might be better to back away than make a serious challenge.”
Like other species, male bears will sometimes kill a female’s offspring to get a chance to mate with her; scientists refer to this as sexually-selected infanticide. Nevin’s work suggests that very young bears may be using the rub trees to help them trick potentially killer males.
“It’s really hard to document, but on several occasions the cameras caught cubs who are being chased away from their mother by a large male visiting and rubbing on trees which he has marked. They can visit the tree two or three times in a day, sometimes within an hour of the big male, so it may be that smelling like him makes them safer – related animals smell similar and animals are less aggressive towards relatives,” Nevin says.
As well as improving our understanding of how bears communicate, the results should also help improve bear conservation by affording an insight into the behaviour of secretive male bears. Earlier work in Canada and Alaska has shown that tourist activities can change how adult male bears behave during the autumn salmon-feeding season, which has been the focus of eco-tourism, but spring viewing when the bears are breeding is becoming increasingly popular.
According to Nevin: “Understanding normal behaviour has to be the starting point for managing bear populations and our activities around them. It doesn’t matter whether we’re considering impacts of tourism or sport hunting on these dense North American populations or reintroductions and enhancements in threatened European populations: knowing how these animals interact with each other will help us to make the right decisions.”
Dr Nevin will present his findings on Monday 10 September 2007 at the British Ecological Society Annual Meeting.
Note: This story has been adapted from a news release issued by British Ecological Society.

Fausto Intilla

www.oloscience.com