An uphill climb: scientists discover that animals are moving up a mountain in Madagascar.
Despite the challenges, this is the second time Raxworthy has made the climb. Ten years earlier, the herpetologist from the American Museum of Natural History studied reptiles and amphibians in the mountain's remote forests. On that trip, he found so many specimens--some of which he couldn't even identify--that he knew he would come back one day for another look.
Raxworthy's second survey revealed a surprise: Many of the mountain's animals are on the move.
As Raxworthy and his team make their way up the mountain, they scour the slopes at different elevations, or heights above sea level. They record all of the different reptiles and amphibians living in each spot. As he searches, Raxworthy is disturbed to find that some of the animals he spotted the first lime are missing. "That's always very worrying," says Raxworthy. "When you return to a site, you expect to see what you found before."
As the team continues up the mountain, Raxworthy is surprised to discover some of the missing species popping up. The animals now live in new homes farther up the mountain. The reptiles and amphibians Raxworthy studies are adapted to specific habitats and environmental conditions, so they normally stay in relatively restricted regions on the mountain. "In the space of 10 years, species moved uphill to an elevation 19 to 51 meters (62 to 167 feet) higher," says Raxworthy. "That's quite a shift."
ESCAPING THE HEAT
Raxworthy says that the massive relocation is likely due to global warming, or the increase in the average temperature of Earth's atmosphere. In the decade that elapsed between the two surveys, the mean annual temperature in Madagascar's capital rose between 0.10 and 0.37 of a degree Celsius. That temperature rise can cause trouble for many reptiles and amphibians. Warmer temperatures can change their habitats, and make organisms susceptible to disease or cause difficulties with reproduction.
To survive, many animals move uphill, where the climate is cooler. But not all animals can relocate. Some of the species Raxworthy studies were already living near the top of the mountain. "They are literally running out of room," he says.
Raxworthy's data suggest that the warming temperatures may have already caused some organisms to disappear. Two species of frogs that Raxworthy found near the summit of Tsaratanana Massif in the first survey were not found during the second one.
HOPE FOR THE FUTURE?
Raxworthy's research shows that if temperatures continue to rise, many other organisms may be in trouble too. He says the only way to protect them is to prevent further global warming.
Burning fossil fuels such as oil and gas to produce energy releases heat-trapping gases like carbon dioxide into the atmosphere, thereby causing the planet to warm. Raxworthy says that people can limit the extent of global warming by using alternative energy sources like solar and wind power, and by decreasing their overall energy use. "The important thing is that we can fix this problem, but there's not much time," says Raxworthy.
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Amphibians were the first vertebrates to live on land. Now, up to a third of amphibian species are threatened with extinction because of a fungus that infects their skin. Amphibians worldwide have died from chytridlomycosls, the disease caused by the fungus. You can learn more about the evolution, anatomy, and behavior of spotted salamanders and poison dart frogs, as well as sea turtles and Komodo dragons, by asking your teacher or visiting the Hall of Reptiles and Amphibians at the American Museum of Natural History In New York City (www.amnh.org).
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EARTH: Climate Change
DID YOU KNOW?
* More than 250 different species of amphibians live in Madagascar. Most of those species--about 99 percent--can't be found anywhere else.
* Most scientists agree that one of the major factors in climate change is people's reliance on fossil fuels. How can you reduce your usage of things like oil, coal, and natural gas? What alternative energy sources could you use instead?
LANGUAGE ARTS: Imagine that you are a biologist on Raxworthy's trips up Tsaratanana Massif. Write a letter home about your second trip. Be sure to include what changes you saw as you climbed up the mountain and what you think these changes mean for the amphibians on the mountain.
You can access this Web link at www.scholastic.com/scienceworld. * The National Wildlife Federation has a page on how global warming is affecting many different species: http://cf.nwf.org/ wildlifeandglobalwarming/effectsonwildlife.cfm.
CHECK FOR UNDERSTANDING
DIRECTIONS: Circle the incorrect word or phrase and write the correct word or phrase below it.
1. Chris Raxworthy is a hematologist at the American Museum of Natural History.
2. During Raxworthy's second trip to Madagascar, he noticed that many of the species were at the same location as they were on the first trip.
3. Rising temperatures do not affect the health of reptiles and amphibians.
4. The reptiles and amphibians Raxworthy studies normally roam through different regions on the mountain.
5. A way to prevent the average temperature of Earth's atmosphere from rising is to increase our use of fossil fuels.
1. hematologist/herpetologist 2. the same location as/higher elevations than
3. do not affect/have a negative effect on 4. roam through different/stay in relatively restricted
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|Title Annotation:||EARTH: CLIMATE CHANGE; Tsaratanana Massif|
|Date:||Mar 15, 2010|
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