Author Archives: Susan

09/16/11

Chytrid Fungus: Hope for Fighting Deadly Amphibian Disease

Researchers at Oregon State University have discovered a freshwater organism that might help in fighting the chytrid fungus, which is a principal cause for the worldwide amphibian decline. A freshwater species of zooplankton, called Daphnia magna, could provide a tool for biological control of the deadly fungus whose impact, one researcher has called “the most spectacular loss of vertebrate biodiversity due to disease in recorded history.”

Daphnia magna is a variety of water fleas of the genus Daphnia, some species of which are commonly used as food for aquarium fish. It was known that the zooplankton could devour some types of fungi. Oregon researchers wanted to find out whether Daphnia magna could also consume the chytrid fungus that has been devastating amphibian populations worldwide, including Colorado’s endangered boreal toad.

Through extensive research, scientists confirmed that Daphnia magna could consume the free swimming spores of the fungal pathogen. According to lead researcher Julia Buck, an OSU doctoral student in zoology, in an Oregon State University press release:

We feel that biological control offers the best chance to control this fungal disease, and now we have a good candidate for that. Efforts to eradicate this disease have been unsuccessful, but so far no one has attempted biocontrol of the chytrid fungus. That may be the way to go.

Now scientists need to conduct field studies to confirm the zooplankton’s effectiveness in a natural setting. The OSU scientists have found that Daphnia inhabits amphibian breeding sites where chytrid transmission occurs and may be able to stem the unprecedented population declines and extinctions.

For background on the chytrid fungus, please see the video below that we found on the Save the Frogs site, produced by the National Science Foundation:

The Oregon State University research was reported in the journal Biodiversity and Conservation, and was  supported by the National Science Foundation. Click here for the full report.

09/10/11

How Do Hurricanes Affect Wildlife?

After Hurricane Irene, Susan posed the question to me: what happens to wildlife during a hurricane? I decided to try and find out the answer to this.  Because Irene affected such an enormous area—from North Carolina to New England—it’s difficult to generalize. I began with the National Wildlife Federation’s Seven Things to Know about How Hurricanes Affect Wildlife, which I’ve summarized below. Please see the NWF site for more information.

Wind Dislocation

The powerful winds in a hurricane can blow birds off course and push them away from their home habitat. While songbird and woodland birds can cling to branches, and woodpeckers and other cavity nesters ride out the storm inside trees, sea birds and waterfowl are exposed to the high winds.

Other tree dwelling animals are also effected. During Irene, many baby squirrels were orphaned after being blown out of their nests in trees.

Courtesy www.humanesociety.org

Tree Loss

Loss of coastal forests and trees can be devastating to wildlife dependent on the trees for food and habitat. High winds will often strip trees and bushes of food for wildlife: fruits, seeds, and berries.

Dune and Beach Loss

Storm surges, wave action, and winds can cause beach and dune erosion, which has severe effects on species, especially those that live in ecological niches in the sandy areas and dunes of coastal barrier islands.  Sea turtle nests, for example, can be washed out, or a water surge, called a “wash over” that can submerge these nests. Tern and plover nesting areas may also be affected. In some cases, the storm can cause an entire beach area to disappear.

Saltwater Intrusion

The sustained and powerful winds of a hurricane may cause salty ocean water to pile up and surge onshore.  These storm surges can be huge. Hurricane Irene’s surges brought water levels that were as much as 8 feet above normal high tide. In addition to the physical damage this causes, the salt contained in sea water dramatically shifts the delicate balance of freshwater and brackish wetland areas. Creatures and vegetation that are less salt-tolerant may be harmed and many may not survive this influx of sea water.

Freshwater Flooding

Heavy rains generated by hurricanes dump water in coastal area river basins (called watersheds) and this, in turn, can send vast amounts of fresh water surging downstream into coastal bays and estuaries.  This upsets the delicate and finely tuned freshwater/salt water balance that can be so vital for the health of these ecosystems.

Turbidity

Heavy rainfall in upstream areas also washes soil, sediment, and pollutants into coastal and marine environments.  Similarly, sediment can wash over coral reefs, blocking needed sunlight.

Marine and Aquatic Species

Hurricane Irene generated massive waves and violent action on the surface.  When hurricane Andrew hit Louisiana the government estimated that more than 9 million fish were killed offshore.  Similarly an assessment of the effect of that same storm on the Everglades Basin in Florida showed that 182 million fish were killed.

Close to Home

Where I live in Hoboken, New Jersey, many of the city’s residents (including my family) were subject to a mandatory evacuation because of the danger of flooding; in worst case scenarios, possible storm surges were predicted to cause water to rise to the second story of the city’s apartment buildings. While the flooding wasn’t as severe as predicted, we did notice that the water on the sidewalks, in our basements, and backyards smelled toxic. Considering that this water flows into storm drains and eventually into waterways is disturbing. This “witch’s brew,” as it was called in various news reports, consisted of raw and partially treated sewage, chemicals from industrial facilities, bacteria, oil, and gasoline.

This commentary by Jeff Tittel in the New Jersey Newsroom.com about the possibility of this toxic brew being released during hurricanes from New Jersey’s many superfund sites was disturbing:

The New Jersey DEP only has one inspector reviewing institutional controls and caps and ensuring flooding and other impacts do not impact the controls. We have 118 superfund sites, 16,000 contaminated sites, and 7,000 sites that have been remediated, some of which are very complex. There are about 500 toxic sites near our rivers and about 3,500 are located near groundwater sources and 500 near major water supply wells. Flooding and polluted stormwater could result in toxins from these sites entering our waterways.

The other day I heard about a woman in Hoboken who sloshed around in the water in flip flops the day after the hurricane and who now has a serious infection. I could smell this toxic brew right in my own flooded basement and backyard. This can’t be good for wildlife (or for people either).

Hoboken after Hurricane Irene. Photo by Mary Jo Rhodes

How did Hurricane Irene affect the environment and the wildlife in your area?

08/29/11

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

Tadpole Metamorphosizing into Frog

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!