If you open a window or step outside and listen carefully, pausing for a
moment to filter out shouts, laughter, music, and cars, you’ll hear a different
Carleton soundtrack. The past few weeks the chorus has been growing; voices
swelling and filling the evening air near ponds, drainage ditches, rivers, and creeks.
Spring has sprung, and the amphibian world is making its presence known. Chirps,
squeaks, trills, and rumbles fill the night, deceptively loud for the diminutive size of
the frogs and toads making them. The Arboretum is home to eight species of frogs
and toads, several of which are already calling.
The Arboretum office keeps track of amphibians, conducting a three-part
frog and toad survey every spring. The survey not only tracks when and where
different species are breeding, but also represents a general picture of Arboretum
health. Amphibians are ecological indicators, that is, the health of frog and toad
population is generally indicative of the overall health of the environment.
Amphibians have porous skin, which allows oxygen and water to pass through to
maintain homeostasis and respiration. This unique aspect also means that
amphibians are especially susceptible to any toxins and stresses in their
environments, such as chemicals from agricultural run-off. A decline in the frog and
toad population is a symptom of a greater problem in the environment, and a sign
that we could be doing a better job of mitigating threats to the land.
The frogs and toads around Carleton, for me, are a comforting backdrop to
my routine, reminding me of the natural processes in the ever-changing cycle that
I’m also a part of. I grew up catching frogs and toads, spending afternoons poking
around creeks, and the familiarity of the amphibian life is reassuring. The next time
you hear a frog, think of it as a sign that the ecosystem around you, that you also
reside in, is continuing to thrive.
- Anna Persmark ’15, for the Cole Student Naturalists