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/. 

 

 

 

The Other Half of Our Mission

 

by Beth Sullivan

Our Mission: We preserve natural habitats in southeastern Connecticut by acquiring and protecting lands, and by communicating the value of these irreplaceable resources.

Communicating the value of these
irreplaceable resources.

Everyone who is aware of Avalonia as a land conservancy in southeast CT,  understands the first part of that statement,  about preserving, acquiring and protecting.  Over the last several years Avalonia has acquired, or is in the process of acquiring, almost 1000 acres.  Now, over 4,300 acres are protected for the future, for generations of wildlife and people. From our shoreline, which is imperiled by rising sea level, to coastal forests that are being lost to development;  from small vernal pools, to swamps and bogs,  ponds, streams and rivers;  from meadows and thickets to forests with rocky ledges and towering old trees;  Avalonia has a wonderful and diverse cross section of habitats to share.

An illustrated sign captures the
interest of a young hiker.

That’s where the second part of the mission comes in: sharing these resources, communicating and educating all who will listen, about the importance of habitat conservation and diversity. Many of us took refuge in nature over this past year.  Our trails saw enormous increases in traffic.   It is always my hope that people truly think about where they walk, see with different eyes, keep their ears alert, when they are on a trail in the woods and not merely walk for exercise with ear phones securely plugged in! You can learn so much, just on your own, by paying attention.

However, sometimes we are lucky to be able to truly, actively, educate people about our preserves, and sometimes they educate us!    A few preserves have informational signage to point out special elements  along the trail.  We are hoping to do a little more of that.  There is a lot of information on our website about each of the preserves, and links to articles that may offer more insight. Hike and Seek has remained popular with children, families and even older adults who have found our trails and preserves to be sources of learning, respite and  exercise.

The students become the educators

This is the time of year when we also begin to think about some special programs that offer different levels of education.   The Conn College Goodwin Niering Center for the Environment will be joining forces with Avalonia for the ninth year!  Since 2013 I have worked with some of the brightest  young minds, enthusiastic, hopeful and eager to participate in some aspect of Avalonia’s work.  Over the years we have had projects from stewardship and on the ground research, to fundraising and social media efforts. We never quite know what direction their projects will take, but in the next semester, you will be introduced to some of them as we learn together.

I am also so very lucky to be working with a great team from UConn on the Hoffman Project.  Through these connections, I myself am learning a lot about forest management, climate change and also ways to impart that knowledge to others.  We are creating more informational signs for trail side learning.  Under the leadership of a Stonington Town Committee member, a professor from GWU,  Avalonia will be offering a series of webinars about how changing climate is influencing our forests and their ability to adapt.  Entitled “Finding the Right Trees for the Right Time”,  the seminars will discuss the planning and planting we are doing to ensure a resilient coastal forest at the Hoffman Preserve.   Find out more on our website here.  We are also planning to work with the local schools and teachers to offer Hoffman as a living laboratory for learning and field work.   At a time when classrooms are often challenging to keep safe, an outdoor classroom may prove perfect!

Putting heads together to explore
life found in a  vernal pool.
(Photo credit:Kim Bradley) 

There are also many Citizen Science opportunities for students and families to participate in, providing opportunities to learn,and to contribute data to the knowledge base about wildlife in our area.   There is an ongoing opportunity to record bird sightings on eBird   https://ebird.org/.   We have just finished the Great Backyard Birdcount   https://www.birdcount.org/   and Project Feeder Watch  https://feederwatch.org/ continues.  Both websites offer great information about observing birds wherever you may be.   Believe it or not, next month we will be watching for the return of the Osprey to their nesting sites. Osprey Nation offers great information and opportunities to monitor these magnificent birds.  https://www.ctaudubon.org/osprey-nation-home. We will also begin to listen for and report,  those first sounds of spring, from frogs and toads in the Frog Watch Program https://www.aza.org/frogwatch,  sponsored locally by the Mystic Aquarium.

We may still be in the middle of winter, but we can think forward to spring. Avalonia provides the land and opportunities to communicate the value of these irreplaceable resources.

At Hoffman, educational signage helps
visitors understand conservation practices.

Citizen science activities can start early and last a lifetime.
Photo credit: Nick Young

Education and outreach can take many forms.

Start thinking spring!

By MaryEllen Mateleska & Beth Sullivan

It is definitely not too early to start thinking spring.

If you are like us, spring doesn’t truly arrive until you start to hear the “peeps” of spring peepers and the “quacks” of wood frogs. These signals let us know that during a walk to the vernal pools of Pequotsepos Brook Preserve and White Cedar Swamp, we may witness the movements of frogs as they hop into the water and hope to see the telltale signs of amphibian breeding season – egg masses!

Spring Peeper-little frog with a big voice

Connecticut diversity

Connecticut is home to 23 amphibian species, including 12 species of salamanders and newts, and 11 species of frogs and toads (including the newly discovered Atlantic Coast leopard frog!). As spring changes into summer, the breeding calls will begin to change as well. The spring calls of the wood frogs transition to the bellows of bull frogs, to the haunting call of the pickerel frog, or the unforgettable squawks of the endangered Eastern spadefoot. What is amazing is that these calls not only create the nocturnal music we’ve all grown to love but provide valuable information on the health of our local wetland and forest ecosystems, including Avalonia preserves.

Bull Frog in full voice. Photograph courtesy of the Mystic Aquarium.

Currently, a third of the world’s amphibian populations are listed as threatened or endangered. While habitat destruction and pollution are the top causes for population decline in our region, invasive species, and diseases like chytrid fungus, are threatening populations not just locally but globally. Now is the time to take actions to help save these vanishing species! Programs like FrogWatch USA train citizen scientists (next training is on February 27!) on how to collect and submit information on frog and toad calls; these calls inform us of any changes in breeding seasons and an estimate of population size.

Green Frog

Jefferson salamander egg masses. Photograph courtesy of the Mystic Aquarium.

Not sure if you can learn calls? Participation in guided walks flipping rocks and logs will help us understand salamander and newt populations.

Spotted salamanders are silent, and not easily found except during breeding season.

Still not sure how you can help? Try washing your shoes, boots and nets after you leave a preserve – this small step will help to stop the spread of any invasive species from one area to another.

Toads prefer to be dry, but go to wetlands to trill and breed.

Although there may still be ice and snow covering the vernal pools and ponds, we are looking forward to the day that we hear the first sounds our local frogs and toads. Happy Frog Watching!

Pickerel frogs sound like a low pitched snore.

Wood frogs sound like quacking ducks.

Frog Watch USA

To get ready for the season, without getting your feet wet yet, please join many of us at the Mystic Aquarium on Feb 27^th , from 6pm-9pm for an introduction (or immersion) into the art of listening for the sounds of spring amphibians and turning into Citizen Scientists by collecting and submitting data. The training is free but registration is required and participants must be at least 15 years of age This is a great family activity. Email educationinfo@mysticaquarium.org  to reserve your spot.

Once you are ready to listen, search, and identify, head out to an Avalonia Preserve that has wetlands. There are many: Pequotsepos Brook, White Cedar Swamp and Deans Mill Preserve, Knox Family Farm, Knox Preserve, Paffard Woods, Preston Nature Preserve, Henne Preserve, Babcock Ridge, Bindloss Preserve, Hoffman Preserve. These are just a few of the easily accessible preserves with wetlands just waiting for Spring. Check the Avalonia website for preserve descriptions, locations and directions.

Photographs by Beth Sullivan unless otherwise indicated.