Thom Smith | NatureWatch: Pesticides cited in amphibian deaths


Q: I read your article, "Watch for salamanders, frogs on roads," The Berkshire Eagle, April 7, and I have a question: Do lawn pesticides harm amphibians? My reason for asking is this: When we moved to our neighborhood in Dalton back in 1992, lots of frogs and toads lived here, and dozens were killed in the street by passing cars. Since then, more and more of our neighbors have been using lawn services that include pesticide treatment and weed killers, and the population of frogs and toads has dropped to almost none. After they spray, I occasionally find a frog or toad on the sidewalk — not crushed, just dead. We used to hear spring peepers every year in April and May. Last spring, I heard only one lonely peeper calling.

Are we are headed for "Silent Spring," thanks to my neighbors' desire for lush green lawns? Is there a remedy for this poisoning of Mother Earth?

— Glendyne W, Dalton

A: A less technical explanation from Mother Jones Magazine: "Amphibians (cold-blooded vertebrates) show more effect to pesticides than any other vertebrate group from terrestrial as well as the aquatic environment. Risk for pesticide exposure increases due to permeable skin for water and ions. Contamination may cause alteration in their behavior." (Source:

From Save The Frogs: "Pesticides (insecticides, fungicides, herbicides, etc...) are toxic chemicals that generally undergo little to no testing on amphibians prior to their being approved for use. Unfortunately, the law of gravity has it that many of these pesticides end up in waterways, where amphibians live and breed. Amphibians have permeable skin that is highly absorbent, making them extremely susceptible to pollutants and pesticides. (Source:

For even more information than you expected, read the article from the Journal of Toxicological Analysis, published Nov. 26, 2018, "Impact of Pesticides on Amphibians: A Review. J Toxicol Anal Vol.1 No.2:3.Copyright: 2018 Islam A, et al." "Amphibians can be indirectly exposed to pesticides through runoff from land that has been treated with pesticides, and even through skin contact with contaminated soil. A 2013 study published in PloS ONE found that amphibians are vanishing at a rate of about 3.7 percent each year, which means that they will be absent from half of the habitats they currently occupy in about 20 years. An abundance of scientific literature has demonstrated the negative effects of an array of commonly used pesticides on amphibians: delayed metamorphosis, immunosuppression, hermaphroditism, sex reversal, and outright mortality. There are over 18,000 registered pesticides in the USA. According to the Center for Biological Diversity, 200 million pounds of pesticides are applied each year in California alone, and two billion pounds throughout the U.S.A. annually." For more information, visit

Article Continues After These Ads

From The Smithsonian: Even in remote Sierra Nevada ponds, The Los Angeles Times reports, frogs are not safe from the deleterious effects of pesticide exposure. Ten poisons applied to crops up to 100 miles away are turning up in the frogs. One of these is "a degraded form of DDT," the infamous pesticide of Rachel Carson's "Silent Spring," which has been banned in the U.S. since the 1970s. Amphibians are particularly sensitive to chemicals in the environment since they have one webbed foot in the terrestrial world, another in the aquatic world. And many amphibious species go through a metamorphosis during their lifetimes, which makes them extra sensitive to developmental disruptions. In this study, U.S. Geological Survey scientists sampled tree frogs in seven sites in the Sierra Nevada, including in national parks.


Q: On many occasions, I have observed squirrels hopping up on my deck railing, near the bird feeders, and urinating and/or defecating before heading to the feeders. Are they marking their territory or is this just a (frequent) coincidence?

— Nancy S.

A: Both.


Another subject close to my heart is illegal exportation and importation of any wild animal, that often dies in shipment or its parent(s) are killed to capture the young. These animals are frequently endangered, and some even are slaughtered for body parts. Email Biological Diversity and sign the petition to stop importation of endangered wildlife. Email:


If you'd like to leave a comment (or a tip or a question) about this story with the editors, please email us. We also welcome letters to the editor for publication; you can do that by filling out our letters form and submitting it to the newsroom.

Powered by Creative Circle Media Solutions