Amphibians As Indicators of the Environment

by Edin Sisson and Alaine Zhang 

Green frogs sound like a banjo
being plucked!

Avalonia Land Conservancy owns a large variety of wild habitats and local ecosystems and its mission is to steward and manage these habitats in a way that benefits both their ecological health and the  communities surrounding them.  In order to aid in these intentions, one crucial group of animals must be considered as both a concentration of care and a tool to gain insight on environmental health within Avalonia’s Preserves: Amphibians.  Frogs, toads and salamanders are complex organisms that are not only intriguing but are important to focus on when studying local ecology. During the past semester as students at Connecticut College, we partnered with Avalonia to help create awareness of amphibian life on our local preserved lands. In order to do this, we collected data weekly regarding the intensity of frog calls and wanted to create a blog post that reflects the significance of frogs within the areas studied. 

 

Vernal pond at White
Cedar Swamp

There are three main groups that Amphibians are categorized into; urodeles, anurans, and gymnophiones.  Urodeles are composed of newts and salamanders, anurans include frogs and toads all of which are vertebrates.  Gymnophiones are also vertebrates but have no limbs, and are otherwise known as caecilians. Amphibians are one of the oldest types of vertebrates and are distinctive because they live on both water and land at some point during their lives. Frogs and toads spend their early stages of development with gills, and then develop lungs and limbs to be able to survive on land as well. This unique development is what makes vernal pools, swamps, and shallow areas of ponds such great habitats for them to live. In addition to lacking hair and laying eggs, frogs and toads are exothermic, meaning their internal temperature is externally regulated by factors such as the sun. Frogs and toads are active during the spring and summer and hibernate during the rest of the year, usually in the mud of ponds. What we hear most frequently in the spring are the male mating calls, sung to attract females. The males fertilize the eggs after they are laid, during a process called external fertilization. In order to gain the upper hand over other males during mating season, they practice amplexus, in which they climb onto the female and wait for her eggs to be laid so that they can be the ones to fertilize them. Depending on the frog species, mating happens at different times during spring, the duration fluctuates as well depending on factors such as temperature and climate. There are some key differences between true frogs and true toads. True frogs are skinny with smooth, slimy skin and long legs. They leap and jump fairly long distances, and they have an upper jaw with small teeth. Frogs also lay eggs in large, often round, clusters. Toads, on the other hand, are generally warty and dry, live mostly on land, have fat bodies with short legs, and don’t hop that far. They also do not have teeth and lay their eggs in long strands rather than clumps. 

 

White Cedar Swamp is great habitat 
for frogs!

This spring we focused on frogs specifically, which can be hugely beneficial to us as humans, and to the ecological systems on Avalonia’s lands. They control insect populations as they are the main part of their diet, as well as providing food for predators such as fish, mammals, reptiles, and birds. With their skin and eggs being especially permeable, frogs are very sensitive to factors such as pollution, UV light, disease, and microscopic organisms. The pores on their skin allow them to absorb gasses like oxygen through their skin to breathe, but they also make the organisms prone to environmental changes in the water or air. When the pH of water or soil, for example, becomes too low and therefore acidic, materials such as heavy metal dissolve more easily, and therefore create toxins that are unhealthy for the local ecosystem. When exposed to these toxins, frogs are some of the first animals to die, or have mutations. Their small size also makes them susceptible to fatal environmental factors before larger animals like humans even become aware of the issue. There are many reasons for frog population decline including habitat loss, non-native species, climate disruption, parasites, and over-collection by humans. However, where  frogs are generally locally abundant, they are a great, accessible resource for scientists to use to study the changing environment. By recognizing fluctuations in frog populations and breeding time, we can observe what environmental issues might be problematic within our area here in Connecticut, and if possible, address them in productive manners. 

 

Pond at Pequotsepos Brook Preserve

While exploring both Avalonia’s Pequotsepos Brook Preserve and White Cedar Swamp, we heard three main species of frogs: The Spring Peeper (Pseudacris crucifer), the Green Frog, (Rana Clamitans), and the Pickerel Frog (Lithobates palustris). Spring Peepers are small frogs active from the end of the winter until the late fall and the most abundant frog species that we heard at our Avalonia sites. The Green Frog is a green or brown colored frog that feeds on insects as well as small amphibians. Green Frogs usually mate in April and early May but can continue into the summer months. Their call sound similar to the buckling of a banjo, which we heard during our final visits to White Cedar Swamp. Finally, we heard the Pickerel Frog at Pequotsepos Brook Preserve, which is a medium-sized frog with a lower-pitched call. It is also dark-colored somewhat rectangular dark spots and yellow or orange on the underside of its legs.

We performed research on the intensity of frog calls this spring under the protocols of the national Frog Watch USA organization. This organization calls upon trained volunteers all over the US to collect data on local populations of frog species and use it to monitor population decline, environmental changes, and potentially make positive steps to protect species countrywide. With the mission statement of Avalonia being to “[preserve] natural habitats in southeastern Connecticut by acquiring and protecting lands and by communicating the value of these irreplaceable resources,” these goals align extremely well, especially when applied to the conservation of the wetland habitats that Avalonia protects. By monitoring frogs on Avalonia’s lands, we can observe and analyze behavioral and population changes that could correlate with environmental concerns that negatively impact the ecosystems we cherish. 

 

Works Cited:

 

“Frogwatch Training Manual.” FrogWatch USA, www.aza.org/frogwatch?locale=en. 

Marshall, John. “Indicator Species: Using Frogs and Salamanders to Gauge Ecosystem Health.” GRIT: Rural American Know-How, 2021, www.grit.com/departments/indicator-species-zm0z13jazgou/. 

Mosseso, John J. “Green Frog.” Connecticut Frogs and Toads, NBII, wildlifeofct.com/green%20frog.html. 

“Pickerel Frog.” Virginia Herpetological Society, Virginia Herpetological Society, 2021, www.virginiaherpetologicalsociety.com/amphibians/frogsandtoads/pickerel-frog/pickerel_frog.php. 

Signs of the Seasons: A New England Phenology Program, The University of Maine Cooperative Extension, extension.umaine.edu/signs-of-the-seasons/. 

 

 

 

A Journey to Community

 

Over the last 8 months or so, I have had the great pleasure of working with a Local Girl Scout Troop. These are middle school aged students, who have had to juggle a lot during this last year. In addition to their school upheaval, they had also planned to work toward their Silver Award, a high honor in Scouting circles.  Their proposal was to create a pollinator garden at the Parker Brothers Preserve on River Rd. in Pawcatuck.   This sweet garden-like preserve was a somewhat underappreciated parcel, and over the years, the invasives began to take over. It was looking a bit unloved.  As soon as the girls came forward with their ideas, it made me look at the preserve with new appreciation.  We ourselves began to try and uncover and recover its potential.   As the girls began their research and we consulted about their base plan, we stewards began to attack the greater problems.  Over this past year we have untangled many trees, rescued and rejuvenated berry shrubs and cleared some of the stone walls.   The pollinator garden took shape with help from parents and neighbors. Last fall they planted and this spring we have already welcomed pollinators to the early spring flowers.  In a few weeks, the scouts: Nora, Sierra and Kate and their families will celebrate their Silver Award Winning project. 

For them it wasn’t just about making a garden to fulfill a requirement. It truly was helping to create a benefit for pollinators, as well as creating a lovely spot for community members to gather and enjoy being outside again.

Please watch their video here.  Read their report and take some time to visit their garden at the Parker Brother’s Preserve.    Thank you to all involved.  Beth

A Journey to Community by Sierra Redfern

The star of the show - a Monarch!

We began the Pollinator Project looking to change our community for the better.  Make a difference together.  It started as a project for a silver award and became so much more.  We found that we could help others through this project. 

Last fall the preserve was
cleaned up and
the garden dug.

We started on planning our garden, researching on what plants
would work best. We divided the research between the three of us and attended a weekly meeting every Tuesday at 5.  Once all of our research was finished we put our plan into action.  We dug up our garden and cleaned up the area around it.  Now we were ready to get our plants!

Nora's PAWSOME
dog treat fundraiser!

One of our girl scouts, Nora, had raised money selling dog treats so we could fund our project, so we purchased our plants and began to plant them.  They were all perennials so they could come back every year without our help.  We wanted our project to last a long time.  Our garden was planted but we weren’t done.  We still had to add our butterflies!  Because you can’t have a butterfly garden without butterflies!

We had to wait though because the best time to release these insects is near the end of April, so we decided we weren’t done quite yet with pollinators.  We all collaborated on a 3 part video explaining the importance of pollinators, why they’re going extinct, and how we can save them.  This was one of the most important parts of our project.  And once we were done we got to share it with local areas that wanted to help spread our message. (Editor's note: You can watch it here!)

Early spring bulbs welcomed the insects!

To bring some more passion to the garden we made signs for our plants, a care tip book, and painted rocks.  All to help bring our garden to life, and once our butterflies are released then our garden will have truly been completed.  Completed but not finished, the whole point of our silver award was to give back to the community, and our garden will help bring more pollinators to the neighborhood, bring people together, and make some new memories.

Getting donations from Stonington Gardens 
and Pequot Plant Farm

Planting in the fall

Later this season, there will be many more
welcoming flowers for bees!