I leaned against a fence post on a warm night last week and listened to a chorus of frogs calling from a nearby pond.
In the still night air I could clearly hear the calls of bullfrogs and green frogs calling from the water and gray tree frogs emanating from the tall wetland grasses.
The chorus was calming - a sign that the hot sun that had baked the earth all day had now yielded to the relief offered by the night sky.
And the frogs were taking full advantage of it as their calls - all three distinct but meshing perfectly, filled the night sky.
It was a good sound, but one that one day may never be heard.
A recent study yielded some startling findings when it comes to frogs, toads and salamanders.
They’re declining. Apparently faster than we believed.
In the 1990’s research first showed that amphibian populations were dropping. The new study showed that the drop is continuing and things haven’t stabilized.
The study was released on May 22 and published in the scientific journal PLOS ONE and the reaction among the biology community was one of serious concern.
“The paper points to some startling declines,” said David Miller, assistant professor of wildlife population ecology at Penn State University. “What is most disconcerting is that these declines are occurring for not only the species that we already knew were threatened or endangered but also for the species that were considered low concern.”
The declines are occurring everywhere in the country, including the swamps, ponds and bogs of Pennsylvania. The fact that it shows amphibians once considered stable are declining is startling.
Does that mean that future generations, or even our generation, may one day no longer hear a big bullfrog bellow from a pond?
I thought about that as during a last-minute gobbler hunt on Friday morning. I approached a beaver pond nestled deep in the woods and was serenaded with an early morning chorus of pickerel frogs. It was a good sound to wake up to in the springtime woods, and with the study fresh in my mind, I stopped to appreciate the calls of the pickerel frogs a little longer.
Just in case.
According to the study, populations of those amphibians examined vanished from their habitats at a rate of 3.7 percent each year. If that rate continues, some species could disappear from half of the habitats they currently occupy in about 20 years, according to the report.
For those species that are already threatened, they disappeared at a rate of 11.6 percent each year. If that continues, those species would vanish from half of their habitats in about six years.
“The evidence has been pretty strong that declines have occurred, but it has been hard to make systematic inferences,” Miller said. “This paper quantifies population patterns across the United States, providing a representative picture of what is occurring with amphibians.”
Even in areas where habitats are protected amphibians showed declines, which is cause for further concern. That means whatever is impacting frogs, toads and salamanders in areas vulnerable to things like pollution, disease and poor water quality are also impacting those very areas that are supposed to be protected from such threats.
Basically, the study has concluded that the declines are continuing, they are serious and we should be concerned. But exactly what is causing them isn’t known. Could it be pollution, disease, invasive species or something else?
And could it actually continue to the point that one day we will no longer hear the shrill call of the tree frog, the croak of a bullfrog or the peep of a spring peeper fill the night air?