Frogs and other Amphibians

Aminomethylphosphonic acid alters amphibian embryonic development at environmental concentrations  (Environmental Research, Volume 190, November 2020, MarionCheron,FrançoisBrischoux)   Environmentally relevant concentrations of AMPA (the main metabolite of glyphosate) have been found to affect embryonic survival, development duration and hatchling morphology in spined toads. Non-linear concentration response patterns were likely to occur at low concentrations, meaning that the effect did not increase with the dose – greater effects were found at low concentrations of AMPA than higher levels. The study concluded that regulatory decision-making needs to go beyond the use of high-dose studies to identify official no-effect concentrations.'     'Our experimental concentrations of AMPA were 100–6000 times lower than official Predicted-No-Effect-Concentrations. We found that these low-level concentrations of AMPA decreased embryonic survival, increased development duration and influenced hatchling morphology.'

filed under Wildlife/amphibians 

Pesticides in the real world: The consequences of GMO-based intensive agriculture on native amphibians  (M. Gabriela Agostinia et al, Biological Conservation, Vol. 241, Jan. 2020, 108355)   ' ...we evaluated the effects (survival and mobility) of common pesticides applied by farmers (cypermethrin, chlorpyrifos, endosulfan, glyphosate, and 2,4-Dichlorophenoxyacetic acid) on tadpoles. We assessed these effects in four common amphibian species from South America across 91 ponds located in the Pampas of central Argentina.'

• Tadpole survival dramatically decreased after pesticides reached the ponds.
• 93% of surviving tadpoles exposed to insecticides, exhibited impairment of mobility.
• Glyphosate exposures caused sublethal effects, reducing tadpole mobility in 79%.
• We detected pesticide impacts on amphibians in real exposure scenarios.

Neonicotinoids Found to Change Frog Behavior  Beyond Pesticides, November 15, 2018)  In a study published late last month, scientists from the National Wildlife Research Center in Ottawa, Canada found that chronic exposure to real-world levels of the neonicotinoid imidacloprid limits the ability of juvenile wood frogs to escape a predator attack.

Literature review of impacts of glyphosate herbicide on amphibians: What risks can the silvicultural use of this herbicide pose for amphibians in B.C.?  by  Purnima P. Govindarajulu, Ph.D. includes an EXECUTIVE SUMMARY. "the expected environmental concentration (EEC) of glyphosate herbicides of 1.43 mg a.e./L is at or above the estimated LC50 (lethal dose kiling 50% of the study animals) value for some amphibians." Many serious sublethal effects are known to occur well below this concentration. Indirect impacts also occur...The formulant POEA appears more toxic to amphibians. Alternative formulations that do not use POEA are now available in some parts of the world (but not in Canada) and these formulations have been shown to have much lower toxicity to amphibians. There is insufficient information on the levels of glyphosate contamination in small ephemeral wetlands, which are favoured habitats of amphibians, and which may be exposed to direct overspraying with herbicide under current use guidelines."  also filed under fact sheets/ glyphosate 

Glyphosate Stresses Tadpoles to Produce More Venom  (Beyond Pesticides, August 9, 2017)  Scientists tested the effects of formulated glyphosate products on toad tadpoles through experiments in a laboratory setting, as well as a mesocosm, a controlled outdoor environment that replicates natural conditions. This is not the first instance of glyphosate altering the normal development of amphibians. Earlier this year, the same team of researchers found that glyphosate products reduced the survival and growth of common toads, and otherwise slowed down their development. A 2012 study from the University of Pittsburg found that glyphosate induced morphological changes in the development of leopard and wood frogs similar to those seen under significant predatory threat. The results of accumulated scientific research on stress-induced changes following glyphosate exposure points to underlying flaws in U.S. regulation of pesticides. Ecosystem-wide impacts caused by the secondary effects of pesticide use are rarely, if ever, considered under the risk assessment framework used to register pesticides.

Report Links Pesticide Exposure to Globally Declining Amphibian Population 3/8/2013 12:02:41 PM By Victoria Pitcher. Link to full scientific report. Effects were not restricted to a specific class of pesticides and seem to be influenced not only by the active substance but also the formulation additives  The commercially available Headline formulation caused 100% mortality just after 1 h at the label rate.