08/29/11

Back to School: Thoughts about Grow-a-Frog Kits in the Classroom

It’s back-to-school time again, a time when teachers may be planning their life science classes. What better way to illustrate an animal’s life cycle than by teaching kids about the remarkable transformation of a tadpole into a frog? Unfortunately teachers may decide to use grow-a-frog kits to teach children about metamorphosis.

I have to admit I have mixed feelings about advising teachers not to raise live amphibians in the classroom. As a child, my love of animals was fostered by the various animals I kept at home, including fish and turtles. I probably would have enjoyed having a live frog in the classroom.

But the authors of an article in the Herpetological Review, “Considerations and Recommendations for Raising Live Amphibians in Classrooms,” remind us that the world is no longer a simple place: innocent acts like catching tadpoles and releasing them later into local ponds are much more complicated than they used to be.

Releasing live frogs “grown” in the classroom into the wild can potentially harm native amphibians (even if the animals are native to the area) by possibly spreading infectious diseases, such as the deadly chytrid fungus, a disease that has wiped out entire frog populations. It may also introduce species (such as bullfrogs) that might become invasive and disrupt local amphibians.

After we wrote a few posts discouraging people from buying the Frog-o-Sphere kits, quite a few readers who owned the kits were distressed and emailed us, asking if they should “let the frogs go.” We wrote back immediately, telling them not to release the frogs into the wild. Instead we referred them to frog care sites and books. If you’ve already purchased a frog kit, it is your responsibility to take care of the frog. Releasing it into the wild helps neither the frog nor the environment.

The problems with the classroom grow-a-frog kits are similar. After the tadpole grows into a frog, the children may become bored with it and the teacher may decide to release it into a local pond. Or at the end of the school year, the teacher may give it to a family, who then releases it somewhere in the neighborhood. As advised in the article above: “This should never be done, and in fact, it is illegal in several states. No amphibian purchased or received from any commercial or informal (e.g., a neighbor) source may be released into the wild. This recommendation applies whether the species is technically ‘native’ to the region of release, or not.”

If you decide to purchase a grow-a-frog kit (which we hope you don’t), you will be making a commitment to take care of the frog for its natural lifespan.

How can teachers and parents teach children about the life cycle of frogs without raising live frogs? We would suggest contacting a local nature center and setting up a field trip in the spring, where the children can see eggs and tadpoles in the wild. This past spring while hiking I frequently saw frog egg clusters in ponds and swamps, and it’s fairly easy to see tadpoles as well. A local naturalist will know where to look.

To prepare the children for what they might see in the spring, here are some resources:

The Amphibian Project : Classroom curricula, field projects and hands-on activities, fundraising ideas for students, and links.

Amphibians. 35 min. (Eyewitness DVD) Describes amphibian life cycle and anatomy; behaviors and adaptations; and amphibian characteristics. Grades 5-12

Two frog life cycle plastic sets:

For more information:

Joseph R. Medelson III et al. “Considerations and Recommendations for Raising Live Amphibians in Classrooms,” Herpetological Review, 2009.

The authors of the article above recommend this pamphlet, produced by Partners in Amphibian and Reptile Conservation (PARC) entitled “Don’t Turn it Loose.”

08/21/11

Why Are Beetles Destroying Western Forests?

Recently Susan visited Colorado for a vacation where she has been many times before to visit family. She always enjoys getting out of the city to experience the beauty of the Rocky Mountains. But this time, she was truly alarmed by the sight of dead trees everywhere. She asked me to look into this and write a post about it.

Dead Trees due to Pine Beetle in Bristish Columbia

Courtesy azimuthproject.org

The culprit is the native mountain pine beetle, an insect about the size of a grain of rice, which has been destroying trees in British Columbia, Canada, and across Colorado and Wyoming.

The mountain pine beetle is a predator of many western pine trees, particularly mature lodgepole pines. It must kill the trees in order to successfully reproduce. The beetle typically kill trees already weakened by disease or old age. But even a healthy tree isn’t able to fight off the beetles when they are at epidemic levels.

The beetles attack pines in late summer, dispersing a chemical signal that attracts other beetles to mass-attack the tree. When the beetles bore through the bark of the tree, they introduce blue-stain fungus, which can work quickly to kill the tree. The beetles form tunnels and lay eggs underneath the bark, which hatch into larvae. The larvae spend the winter underneath the bark and emerge as adults in the summer, beginning the cycle again.

The U.S. Forest Service estimates that by 2012, the majority of lodgepole pines in northern Colorado and southern Wyoming will be killed by the beetle. Extensive beetle kill has resulted in ecosystem-wide impacts such as increased potential for wildfires and some loss of other tree species such as Douglas fir.

What has caused this infestation? It appears that global warming is a major factor in the infestation. The beetle eggs, pupae, and young larvae are the most susceptible to freezing temperatures. According to a British Columbian government site, in the winter, temperatures must consistently be below -35 Celsius to -40 Celsius (-31 to -40 degrees Fahrenheit) for several straight days to kill off large portions of beetle populations. In the early fall or late spring, sustained temperatures of -25 Celsius (-13 degrees Fahrenheit) can freeze mountain pine beetle populations to death.

Amy Nicholas, a U.S. Fish and Wildlife Service biologist in Rock Springs, Wyoming, says: “Because of warming temperatures, scientists are now seeing significant beetle impacts even in the high elevation sites occupied by whitebark pine. These sites are usually quite cold and unfavorable for epidemic levels of mountain pine beetle. That no longer seems to be the case.”

In addition to global warming, other factors, such as extended droughts and dense forests, have created a “perfect storm” for the infestation.

Lodgepole pine forests dominate the forested ecosystems of western North America and can provide breeding and foraging habitat for many coniferous wildlife species, including song birds, woodpeckers, and red squirrels.

Research by biologists with the U.S. Fish & Wildlife Service aims to determine which alternative stand types may best support wildlife species until lodgepole stands can regenerate after the ongoing infestation.

Unfortunately the spread of the beetle and its deadly fungus reminds us at Frogs Are Green of another disease linked to climate change, the chytrid fungus, that is wiping out populations of frog species worldwide.

Most of the information for this post came from a press release issued by U.S. Department of Fish and Wildlife, Wyoming: Perfect Storm Fuels Mountain Pine Needle Epidemic

08/14/11

Frogs: A Chorus of Colors in NYC at American Museum of Natural History

The other day Susan and I ventured into New York City to see the traveling exhibit Frogs: A Chorus of Colors again at the American Museum of Natural History because we enjoyed it so much the first time we saw it. The exhibit features over 200 live frogs in re-created natural habitats, complete with rock ledges, live plants, and waterfalls.

If you live near NYC or need an excuse to visit the Big Apple, we highly recommend this exhibit, which runs until January 8, 2012. Most of the exhibits are at eye level for even the youngest kids, who had fun trying to spot the well-camouflaged frogs. They can also push buttons to hear frog calls, view videos of frogs in action, and even dissect a frog virtually with a program called Froguts. (Teachers take note: the kids were fascinated by this and several tried their hand at it.)

Here are a few things you will learn:

The Cuban tree frog is probably the smallest frog at only 1/2 inch in length
The cane toad lays 35,000 eggs in a single string
The Australian water-holding frog digs in desert soils and can remain underground for years
The world’s biggest frog is the West African goliath at 15 inches and weighing 7 lbs, as much as a newborn infant.

The stars of the exhibit were the dart poison frogs. Their jewel-like colors warn predators not to eat them. One type of poison dart frog can kill 20,000 mice or 10 people with its poison, which is excreted through the skin. As the label on this exhibit says, “Don’t kiss these frogs!” The baby dart poison frogs, hiding in the palm leaves, were pretty cute. They were about the size of a fingernail.

Susan took some videos of the frogs in the exhibit:

Note: This is a partial repost of our original visit in 2009

08/6/11

The Froglog: Helps Frogs Avoid Drowning in Pools

This summer, my family and I have been visiting public gardens in the New York area and have noticed something in each one we’ve visited—drowned frogs in the gardens’ fountains and pools. We thought we’d repeat a blog post from a couple of years ago about this problem. It has such an easy solution: frogs just need a way out of the pools. I watched some frogs trying to climb out of the stone pools and they weren’t able to get out. They need a ramp, a step, or some other way to escape. Here’s one way that frogs can escape: The Froglog.

A couple of summers ago, we received a wonderful photograph taken by Mary Lascelles for our photo contest of a frog (whom she named Fritz) who hung out on the filter line in her pool sunning himself. Luckily, Fritz never fell in the pool.

fritz-mary-lascelles

Unfortunately many frogs do fall in pools and are poisoned by chlorine, which is absorbed into their bloodstream through their permeable skin. Recently on the Mother Nature Network blog, I read about a new invention, called a Froglog, that is an escape ramp that helps frogs and other small animals escape from pools.

The froglog was created by Rich Mason, a wildlilfe biologist with the U.S. Fish and Wildlife Service, who was disturbed that so many frogs and other animals were dying in pools. The froglog is a thick foam tile with angled edges that allow frogs to climb out of the pool. The froglog can also be used in hot tubs, spas, fountains, and backyard ponds.

As Mason writes on his website, due to suburban sprawl, pools are now often built close to the natural habitats of amphibians. He mentions a friend with a pool in Maryland who found over 50 animals trapped in his pool in one night.

Check out this video of frogs and turtles using the froglog escape ramp. And if you have a pool, fountain, etc… and live in an area with lots of wildlife, definitely consider getting a froglog!

07/30/11

Frogs Legs: Worldwide Consumption Contributing to their Extinction

Eating frogs legs is a bit of a joke to Americans. Most of us would never consider eating them. Yet we need to take this very real threat to frogs seriously.

A recent article in Scientific American, “How Eating Frogs Legs Is Causing Frog Extinctions,”* listed some pretty amazing statistics:

Over two thousand metric tons of frog legs are imported into the U.S. each year. Another two thousand metric tons of live frogs are imported every year for sale in Asian-American markets.
The European Union imports an annual average of 4,600 metric tons of frog legs, mostly to Belgium (53 percent), France (23 percent) and the Netherlands (17 percent), the equivalent of about one billion frogs.

The numbers in the Scientific American article come from a recent report, “Canapés to Extinction: The International Trade in Frogs’ Legs and Its Ecological Impact” (pdf), released on July 26 by the wildlife conservation groups Pro Wildlife, Defenders of Wildlife and the Animal Welfare Institute.

According to Alejandra Goyenechea, acting director of international conservation programs for Defenders of Wildlife:

Humans have been eating frogs for ages. But today the practice is not sustainable on a global scale. Billions of frogs are traded internationally each year for human consumption, and that industry is responsible for depleting wild populations, spreading deadly disease, and allowing invasive species to destroy the health of native ecosystems.

This huge demand for frogs legs is contributing to frog extinctions for two reasons:

Too many frogs, collected from the wild, are depleting natural populations
The international trade in frogs legs and live frogs is the major reason for the spread of the deadly chytrid fungus (Batrachochytrium dendrobatidis), which has already been blamed for amphibian extinctions around the globe.

According to the report, most frog and frog leg imports to the U.S. come from China, Taiwan, Ecuador, Brazil, the Dominican Republic, Vietnam, Mexico and Indonesia. One of the species farmed is the Bullfrog, an American native species that has spread around the world. But Bullfrogs are one of the most notorious carriers of the chytrid fungus. According to Save the Frogs, as quoted in the SciAm article:

A recent study estimated that 62 percent of the bullfrogs entering California from Asian frog farms are infected with the chytrid fungus. Bullfrogs serve as perfect vectors for fungus, as the frogs can survive infection loads of millions of chytrid zoospores. Because the infected frogs don’t die from the fungus, they are able to spread the pathogen to native amphibian populations.

Bullfrogs are usually resistant to the chytrid fungus and rarely, if ever, die from exposure to it. Most other amphibian species have an 80 percent mortality rate when exposed to the fungus.

Exact statistics on which species are being imported and eaten are incomplete, because most imports are already skinned, processed and frozen, making them hard to identify.

The three organizations behind this report are now calling for increased regulation of the frog trade under the Convention on Trade in Endangered Species of Wild Fauna and Flora (CITES). That agency has the authority to restrict some hunting and harvesting, create humane standards for frog handling and killing, set monitoring criteria for wild populations, and require that all imported meat be frozen, which would slow the spread of disease.

Last year, the U.S. Fish and Wildlife Service asked for public comments on a proposal to ban the import of live frogs under the Lacey Act, which regulates the import or transport of wildlife species that are either dangerous to humans or the environment. The public comment period ended in December, but so far there is no word yet on if the proposal will become law.

For more information:

*Information from this post comes from:

Scientific American, “How Eating Frogs Legs Is Causing Frog Extinctions

Defenders of Wildlife: Amphibians in Crisis

Save the Frogs: The Problem with Frogs Legs

07/19/11

Rare Rainbow Toad Rediscovered after 80 Years

Conservation International has announced the rediscovery in Malaysian Borneo of a vanished amphibian: the long-legged Borneo rainbow toad. Below is one of the first photographs ever of this long-legged brightly colored toad.

Inspired by Conservation International’s (CI) Global Search for Lost Amphibians, scientists with support from Universiti Malaysia Sarawak found three individuals of the missing toad species, up a tree during a night time search after months of scouring remote forests.

The Sambas Stream Toad, or Bornean Rainbow Toad (Ansonia latidisca) was last seen in 1924. Prior to the rediscovery, the mysterious and long-legged toad was known only by illustrations. The rare toad was listed by Conservation International as one of the World’s 10 Most Wanted Lost Frogs, in a global campaign to seek out amphibians that have not been seen in a decade or longer.

Dr. Indraneil Das of Universiti Malaysia Sarawak (UNIMAS) and his team searched at night along the high rugged ridges of the Gunung Penrissen range of Western Sarawak. They did not find the elusive toad after searching for several months, but the team didn’t give up. Dr. Das eventually changed his team’s strategy to include higher elevations and they resumed the search. Pui Yong Min, one of Dr Das’s graduate students, found a small toad up a tree. When he realized it was the long-lost toad, Dr. Das expressed relief at the discovery:

Thrilling discoveries like this beautiful toad, and the critical importance of amphibians to healthy ecosystems, are what fuel us to keep searching for lost species. They remind us that nature still holds precious secrets that we are still uncovering, which is why targeted protection and conservation is so important. Amphibians are indicators of environmental health, with direct implications for human health. Their benefits to people should not be underestimated.

Amphibian specialist Dr. Robin Moore of Conservation International, who launched the Global Search for Lost Amphibians to raise awareness of the serious plight of the world’s declining amphibian populations, also expressed disbelief when Das shared the good news. As he said, “It is good to know that nature can surprise us when we are close to giving up hope, especially amidst our planet’s escalating extinction crisis. “

The Global Search for Lost Amphibians, launched by Conservation International (CI) and the IUCN Amphibian Specialist Group (ASG), with support from Global Wildlife Conservation (GWC), sought to document the survival status and whereabouts of threatened species of amphibians which they had hoped were holding on in a few remote places.

The search took place between August and December 2010 in 21 countries, on five continents, and involved 126 researchers. It represented a pioneering effort to coordinate and track such a large number of “lost” amphibians. The goal was to establish whether populations have survived increasing pressures such as habitat loss, climate change, and disease, and to help scientists better understand what is behind the amphibian crisis.

After 80 years, the rainbow toad is most definitely ready for his/her close up: