Frogs, toads and other amphibians disappearing faster than thought: study By Baltimore Sun, adapted by Newsela staff on 05.30.13 Word Count 782 A spotted salamander (Ambystoma maculatum). Photo: Greg Schechter BALTIMORE Some of the more notable signs of springtime appear to be fading away, as a new study finds frogs, toads and salamanders disappearing quickly across the United States. Scientists with the U.S. Geological Survey (USGS) and a couple of universities report that declines in environmentally sensitive amphibians are more widespread and more severe than previously thought. Even the most common critters appear to be losing ground. And worse, they also seem to be vanishing from ponds, streams, wetlands and other supposedly protected areas in national parks and wildlife refuges. What we found was a little surprising, said Evan Grant, a USGS wildlife biologist. Grant, who monitors amphibians in the Northeast, co-wrote the study.
If the trend continues, the researchers say, some of the rarer amphibians could be gone from roughly half the sites where they are now found in as few as six years. More common species could see similar declines in 26 years. A Broad Picture Of Amphibians Disappearing Researchers have known for some time that some frogs, toads and salamanders were in trouble. But until now they had not developed a broad national picture of how fast they were disappearing. Besides fascinating children of all ages, amphibians help control mosquitoes and other insects. They are also important sentinels for changes in the environment, because they spend part of their lives in water and part on land. They are cold-blooded, depending on the sun s warmth to stay active, and breathe through their skin, which makes them sensitive to changes in water quality. Amphibians are a good indicator of what s going on, said Joel Snodgrass, a professor and chairman of biology at Towson University. It is hard to observe the animals' behavior because they tend to lurk in the water or under rocks, Snodgrass said. The new study is valuable because it made repeated checks over many locations for a long time. Researchers looked and listened for amphibians at nearly three dozen sites over nine years. Researchers had not expected to see declines in many of the more common species. Earlier studies indicated perhaps one-third of the nation s species were losing ground. So researchers had expected to find some species improving while others faced trouble. Surprise! Common Species Also Declining But looking at results for 48 species across all the sites, the study showed a decline in how often they were found where they normally live. On average, the number of locations where amphibians could be found shrank 3.7 percent per year. If that continued, they would be in half as many places in about 20 years. We don t know how long it s been going on or whether it s a trend that will continue, said Michael Adams, a USGS ecologist in Oregon. The study did not attempt to identify the cause or causes for the declines. Amphibian losses have been linked previously with development, disease, chemicals, climate change and even a new species being added to a habitat. While a fungal disease blamed for killing frogs in other countries is found in the United States, Adams said, we re not seeing patterns that would help us make that link.
The researchers limited their monitoring to sites controlled by the U.S. Department of the Interior, so development likely had little direct effect on the amphibians habitat. The fact that we see declines even in protected areas means there is some larger-scale issue going on with amphibian populations, Grant said. Parts of the nation suffered severe but not unprecedented drought during the study, the researchers noted. That might have reduced the amount of rain sustaining wetlands and ponds. Salt And Frogs Don't Mix Scott Stranko, a government biologist in Maryland, said there have been declines in some of the salamanders more sensitive to changes in landscape or water quality. It s pretty conclusive that where you have urban development you lose salamanders and probably some frogs as well, said Mark Southerland, a private consulting ecologist who has worked with the Department of Natural Resources. The Northern two-lined salamander, for instance, appears to be pretty tolerant of changes to its habitat. It is still found fairly widely, he said. But other apparently more sensitive species show up less often. Another factor likely contributing to amphibian declines in urbanized areas such as Baltimore is the widespread use of salt to keep roads clear of ice and snow, Snodgrass said. Changes in the salt level can kill the freshwater aquatic insects on which salamanders and frogs feed. And the salt also poses a direct threat to amphibians. Because they breathe through their skin, increases in water salinity can cause them to lose vital fluid from their bodies. Basically, they die of thirst in an aquatic environment, Snodgrass said.
Quiz 1 The scientist structures his argument that amphibians are disappearing by asking a rhetorical question and then presenting the answer drawing a conclusion and providing examples to back it up presenting and disproving an opposing view providing a personal anecdote or story 2 In order to show the importance of amphibians, the article's author does all the following EXCEPT providing a connection between water quality and amphibians stating possible causes for the disappearance of amphibians describing how amphibians largely benefit the environment describing a connection between children and amphibians 3 What is the reason amphibians are dying of thirst in urban areas? There was a severe drought in the area. The frogs are contracting a rare disease. Salt on the roads prevents amphibians from being able to breathe. The area's harsh winter froze the ponds and the amphibians' water supply. 4 Which paragraph from the article states the reason why scientists have a difficult time observing amphibians' behavior?
Answer Key 1 The scientist structures his argument that amphibians are disappearing by asking a rhetorical question and then presenting the answer drawing a conclusion and providing examples to back it up presenting and disproving an opposing view providing a personal anecdote or story 2 In order to show the importance of amphibians, the article's author does all the following EXCEPT providing a connection between water quality and amphibians stating possible causes for the disappearance of amphibians describing how amphibians largely benefit the environment describing a connection between children and amphibians 3 What is the reason amphibians are dying of thirst in urban areas? There was a severe drought in the area. The frogs are contracting a rare disease. Salt on the roads prevents amphibians from being able to breathe. The area's harsh winter froze the ponds and the amphibians' water supply. 4 Which paragraph from the article states the reason why scientists have a difficult time observing amphibians' behavior? Paragraph 8: It is hard to observe the animals' behavior because they tend to lurk in the water or under rocks, Snodgrass said. The new study is valuable because it made repeated checks over many locations for a long time. Researchers looked and listened for amphibians at nearly three dozen sites over nine years.