CONTENTS
November 1999

Urban Wetlands - Too Much Salt in Your Diet?
Alternatives to Dissection in the Classroom
St. Johns School Pond Update
Sleeping Beauties: When Frogs Hibernate
The A-Team - An Activity for Student
A Wetland Word Search
Fabulous Frog: Gray Treefrog

URBAN WETLANDS CORNER!
By Erin Shapero
Adopt-A-Pond Assistant

Too Much Salt in Your Diet?

It's that time of year again when the snowflakes are flying, snow blankets the ground, and the icicles hang from just about everywhere! This winter wonderland though beautiful can prove dangerous especially in urban areas where much of the ground has been paved over. As the ice and snow build up on roads, driveways and walkways, the pavement becomes extremely slippery. For years, city planners and homeowners have used road salt (and to a lesser extent sand) to solve the icy road conditions (when temperatures are below -10o Celsius salt is ineffective). After a heavy snow fall or ice storm you will routinely see the city salting trucks out on the roads, while homeowners sprinkle handfuls of salt all over their driveways and walkways.

Why do we use salt? Salts are primarily composed of (sodium) chloride, which makes them a low cost, convenient and effective method of dissolving snow, ice and slush. It is not surprising that chloride mixtures, which can include any inorganic or organic salt formulations such as sodium chloride (NaCl), calcium chloride (CaCl2), magnesium chloride (MgCl2), and potassium chloride (KCl), have become the most widely used de-icing agents across Canada.

How does salt work? When salt is poured onto ice what happens is the ice and salt form a saltwater solution. This saltwater solution has a lower freezing temperature than pure water (about -10 0 C depending on the amount of salt used). Since the solution has a lower freezing temperature, it stays as a liquid instead of freezing. Many kilograms of inorganic chloride salts are released into the environment each year�But where exactly do all of these chlorides end up, and what does all of this have to do with wetlands, habitats and amphibians? The answers to both of these questions are closely linked so read on!

Although in the winter months, it is easy to forget about the wetlands and natural habitats that surround us in urban settings, our actions in winter are critical to the habitats of living plant and animals that inhabit wetland ecosystems year round. The use of road salt is one such activity. Yet, until recently, there had been little research regarding the impact of urban salt use on the quality of ground water, and wetland, river, stream and watershed ecology. Environmental groups, university researchers and government agencies are now examining the implications of salt use, and their ecological effects upon these ecosystems.

In the mean time, preliminary studies by Environment Canada(EC) indicate there is cause for concern. EC acknowledges that road salts, if entering aquatic ecosystems, have the potential to harm aquatic and terrestrial plants, and animals through their release into the environment. Once in the environment, road salts are dissolved, dissociated and transported by spray, precipitation, runoff or wind. It is known that chloride compounds enter aquatic ecosystems in a variety of ways, through direct applications of salt to road and driveways, the dumping and disposal of snow piles containing salts, and from the leaching of salt runoff from storage sites. Eventually chlorides from these sources runoff into surrounding streams, lakes, rivers, wetlands and water tables.

Ecosystems adjacent to urban development sites are thought to be more vulnerable to disruptions caused by the addition of chlorine compounds, primarily because the volume of salt used in these areas tend to be greater. In addition, most of the ground in urban centres has been paved, resulting in changes in the landscape which dramatically alter the natural water cycles. This means that water, snowmelt and runoff that would have originally been absorbed directly into the ground will instead runoff directly into storm sewers which empty into local rivers and streams. Polluted storm - water runoff from urban areas brings with it a host of harmful pollutants from the streets such as oil, salt and gasoline, which go directly and untreated into surrounding waterbodies and underlying watertables.

While the impacts of salt use on the human and natural environment are not yet certain, researchers warn that if chloride levels continue to increase at the current rate, the integrity of urban wetlands, streams, rivers, marshes and watersheds and watertables may be at risk, as well as the survival of many aquatic and terrestrial plants and animals. In addition to these adverse ecological effects, there is also the threat that urban drinking water supplies may become heavily polluted with sodium levels exceeding the maximum concentration of 250 mg/L. Anything from in excess of 200-500mg/L may adversely impact aquatic life. There is little known about the human health risks. It can thus be concluded that major organic components of sodium and chlorides are indeed a threat to water quality.

The problem of high levels of chloride in waterbodies is not an easy one to solve as chloride is not easily removed from water, due to its solubility, and unreactive nature. If you consider that road salt can cause vehicle erosion, and the disintegration of concrete over a period of time, it is little wonder that it may be responsible for damaging plant and aquatic life, and threatening the quality of urban water supplies across Ontario.

WHAT YOU CAN DO: Although the problems surrounding the use of road salt are complex and not easily solved, there are simple measures that you can take to ensure that you are not contributing to the degradation of local ecosystems in your area. You can help by encouraging your family members and friends to reduce the use of road salt they put on the driveway, let them know there are alternatives such as sand, as well as removing the ice with a metal shovel or pick axe. And remember, what eventually goes into the sewer or down the street eventually finds its way into the water ecosystems we as humans depend on, as well as terrestrial and aquatic life that swim, breath and live in our Wetlands, rivers, streams and lakes.

ALTERNATIVES TO DISSECTION IN THE CLASSROOM
by: Peter Wonnacott
Adopt-A-Pond Assistant

For many years, one of the key components in high school biology classes, has been the classroom dissection. But now things are beginning to change, as students and teachers are beginning to question the morality and practicality of this exercise, and how much students actually gain from conducting dissections. Another factor of concern is the environmental impact of these dissections. This is an important issue for amphibian conservation because one of the most popular and commonly used species for dissections is the Leopard Frog (Rana pipiens).

As Leopard Frog populations are in decline in North America, many wonder if collection for the purpose of dissection may actually be accelerating this decline. So, why are these frogs are still being used in high school labs?

Many teachers still place a value on the importance of the hands - on experience of dissections. In the past if a student chose not to do a dissection there was often no way of making up for the information covered in the lab. The students would consequently learn about frog anatomy from textbooks, figures, and diagrams, which were often not effective or interesting, due to poor graphics. Now there are many alternatives to actual dissections, teachers can use to instruct lessons on amphibian biology and anatomy.

With technology now available in the form of computer programs and internet sites, dissections could become a thing of the past. Computer programs are now a very worthwhile alternative, with the development of detailed realistic graphics. Some companies are even developing three- dimensional graphics to be viewed with special glasses. One particular company that has been at the forefront of frog dissection graphics is Digital Frog International. Digital Frog International has just recently released their second edition of the Digital Frog dissection, Digital Frog 2.

If classroom computers are accessible and available, one of the major benefits of computer programs, such as Digital Frog, is that in the end they can turn out to be less expensive than having to purchase entire class sets of specimens. This means that there is only a one-time cost for the program and the computers instead of the annual cost in acquiring specimens for each class. For more information about Digital Frog International please check out their web page at www.digitalfrog.com.

The internet is also an excellent resource for issues relating to dissection as well as finding ways around doing a real live dissection in the classroom. Just by typing "Alternatives to Dissection" into any of the search engines you find many different options. Some of these include the "Virtual Frog" found at www-itg.lbl.gov/FROG, and the "Interactive Frog" at teach.virginia.edu/go/frog/menu.html. Both of these sites include visuals of the frog and all of its biological systems. The Interactive Frog includes pictures of an actual dissection, while the Virtual Frog uses an animated cartoon frog. For more than just frog dissections there is a list of different dissections on the internet at www.alaska.net/~zimco/dissect.htm. This list includes virtual dissections of earthworms, fetal pigs, and starfish as well as many others. Also on the internet are many different organizations and their policies surrounding the ethical issues of dissections. This debate can also be useful for students to research and examine the pros and cons of dissection.

Also available are dissection anatomy books or anatomy colouring books that can be used as alternatives or supplements to dissection. These books give good diagrams and descriptions of biological systems and functions.

Another option is to record the complete dissection procedure for the students to watch on video. This is an option that allows everyone to see what is going on, and it also allows for a complete and thorough dissection, because the educator is performing the dissection.

Whether these alternatives are used for the single student who voice a concern, or opposes dissections, or for the whole class, the class needs to develop a respect for the animals. Before entering into the dissection unit, discussions with the students about any of their concerns, the environmental impacts, animal rights, and the morality of dissections should be conducted. If this is done prior to the dissections, the students will respect the animals and hopefully learn more from them.

ST JOHNS SCHOOL POND UPDATE!
Contributed by: Mrs. L. Aucoin
St. John School, Red Lake ON

This year, the St. John students had a wonderful surprise when they came back to school. When they made their first visit of the year to their pond� the pond had undergone amazing change! The cement blocks, cable and other building supplies had vanished. In their place was green grass, warm brown earth. The sweet smell of clover hung in the air and as they arrive three ducks took to the air� where there are ducks, there are frogs! Sure enough, sitting at the pond edge was a little brown frog. The children were delighted.

This was quite a change for the pond. Four years ago, when the first class adopted the pond through the Adopt-A-Pond program sponsored by the Toronto Zoo, the pond was dying. Not only was there building debris, but oil on the water and paint cans lying on the bottom. Small insects were caught on the banks, covered in black goo� dying. We didn't see one frog; an endangered species that the children were interested in preserving.

The class began to clean up the pond. They brought their boots, rakes, shovels and together they began year after year to drag garbage out of the pond. Year by year, the water became clearer and cleaner. Frogs and toads began to appear� and of course, the ducks too!

Last summer, the Grade 4/5 class invited the local newspaper woman to come in and discuss the pond with them. They told her that they were frustrated that the garbage they had pulled from the pond was ending up right back in the pond again! Four years ago, the town council had promised to pick up the garbage from the pond. Over the years they had stopped coming. Now it was time to act. During "Meet the Candidate" night, Steven Blanchard volunteered to attend and ask the candidates their views on conservation and would they support them in their efforts to protect this little pond on block G. Every candidate promised that if elected they would support them. Kids can make a difference.

The teachers and students of St. John School are very proud of Steven and all the children that have protected this pond over the years. When you walk there today, a sign proudly announces that this pond is St. John School's pond and two other signs warn "no dumping allowed". Birds sing, small animals wander the bush and frogs croak on the banks of St. John's pond.

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SLEEPING BEAUTIES: WHEN FROGS HIBERNATE
By: Joyce Chingcuangco
Adopt-A-Pond Assistant

Brr! While we're wrapped in our winter coats, mittens and scarves, we wonder what happened to the frogs and toads that leaped and croaked in our ponds last spring.

During the winter, Ontario frogs and toads hibernate and lie dormant. Some amphibians are "freeze-tolerant" and can regulate the amount of water present in their blood and reduce their intercellular space. They can also convert large amounts of glycogen in their liver into glucose to act as anti-freeze. This is how "freeze-tolerant" frogs such as spring peepers, wood frogs, chorus frogs and gray treefrogs are able to prevent tissue damage during these winter months.

Some frogs are not "freeze-tolerant" at all. So how do they survive the winter? Some toads and frogs hibernate down below the frost line. These hibernation areas include soil pockets, leaf litter, sunken logs and vegetation. Bullfrogs hibernate submerged under permanent bodies of water, while toads burrow in sandy soil.

The different adaptations to colder temperatures may also affect the emergence times and the range of these amphibians. Frogs that hibernate in permanent bodies of water tend to come out later from hibernation, are more territorial and tend to breed later in the season. On the other hand, "freeze-tolerant" frogs emerge from hibernation earlier since they can tolerate colder climates and even the occasional spring freeze. They breed in the first spring pools. They also have a wider range since they can withstand colder temperatures. In fact, Wood frogs are even found as far north as the Arctic!

As we shiver this winter while frogs and toads hibernate, we can look forward to the coming of spring when we will hear frogs and toads call in chorus once again!

THE A-TEAM (AN ACTIVITY FOR STUDENTS)

Purpose: To recognize that animals have specific adaptations required for survival in a wetland environment.

What You Need:paper � pencil � imagination

What You Do:

1. Select an animal from the Adaptation Team listed below and create a story, poem or illustration as to how that animal obtained its adaptation for survival in wetlands.

THE A-TEAM

Leopard frog		Bullfrog
Dragonfly		Great Blue Heron
Snapping turtle		Cattail
Mudpuppy		Duck
Garter Snake		Beaver
Mosquito		Black fly
Butterfly		Little brown bat
Snail			Spotted Salamander

OR

Select the animal and adaptation of your choice from the list below:

duck -  webbed feet		beaver - flat tail
great blue heron - long legs	bullfrog - long sticky tongue
crayfish - strong claws		turtle -  hard shell
catfish - barbels		leopard frog - spots
rattlesnake - rattle		waterboatman - long, paddle-shaped legs

2. Send your story to the Adopt-A-Pond Program, and we will print a selection in the Amphibian Voice newsletter.

NOTE: This wetland activity can be found in "Adopt-A-Pond's Wetland Curriculum Resource: A Toadally Awesome Wetland Guide for Educators." (Activity 4.7)

A WETLAND WORD SEARCH

Find the words listed below in the word search. The words can be found either forwards or backwards, up or down, side to side, or diagonally.

Bullfrog � American Toad � Leopard Frog � Pond � Treefrog � Cricket Frog � Wood Frog � Pickerel Frog � Mink Frog � Mudpuppy � Red Eft � Salamander � Water lily � Duckweed � Bulrush � Arrowhead � Toad Abode

FABULOUS FROG: GRAY TREEFROG

Gray treefrogs are masters of disguise. Their skin colour can actually change depending on the temperature in their environment. Low temperature makes their skin colour charcoal-grey while warmer temperature makes their skin bright grey-green. Their ability to change their skin colour not only serves as effective camouflage, but can also help to regulate body temperature by reflecting or absorbing the amount of radiant heat from the sun. These frogs can also be tricky to find for amateur frogwatchers, as their calls can sound like chirping birds!

Other special adaptations include toe-pads that allow it to cling onto smooth vertical surfaces, and a bright orange-yellow streak on the underside of its thigh that temporarily distracts the gray treefrog's predators.

Gray treefrogs feed on a variety of invertebrates including; aphids, beetles, crickets, grasshoppers, moths and houseflies. These agile, long-limbed frogs are "acrobatic feeders" that can leap into the air to catch their prey.

Gray treefrogs are well adapted to the harsh winter climate. They are freeze tolerant and can convert large amounts of glycogen from their liver into glucose to act as "anti-freeze." Due to this adaptation, gray treefrogs can actually survive being frozen for short periods of time.

These frogs overwinter under leaf litter and emerge from hibernation in the spring. On wet or humid nights, male gray treefrogs call out to potential mates while perched on an overhanging branch or rock. Males will actually defend their territory by kicking and shoving the intruder. Female treefrogs choose a mate by nudging the calling male.

The usual time for egg-laying is in early June. Eggs are attached singly or in small groups to the stems of pond vegetation. The eggs hatch within a few days into golden-coloured tadpoles with red tails. After transforming, emerald-green froglets migrate towards the nearest woodlots and shelter under bushes, bark and leaf litter.

Gray treefrogs are versatile and wonderful creatures that have interesting behaviours to observe and study. They are also well-camouflaged which makes finding them a greater pleasure to behold!

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