Widespread Frog Numbers Drop in Farming Areas

Jenn Hoskins
21st March, 2024

Widespread Frog Numbers Drop in Farming Areas

Key Findings

  • In rural Western France, spined toads are less common in ponds near intensive farms
  • The toad population is declining in farmlands, challenging beliefs about their resilience
  • The study suggests modern farming may be harming species once deemed farm-tolerant
Amphibians have long been recognized as key indicators of environmental health, and their global decline has raised alarms about the state of biodiversity. In a recent study by CNRS-La Rochelle Université[1], researchers have turned their attention to the spined toad (Bufo spinosus), a species that has historically been able to coexist with agricultural activities. The study aimed to understand the impact of modern farming practices on the amphibian populations in rural Western France. The research revealed a concerning trend: both the presence and abundance of spined toads were significantly reduced in breeding ponds surrounded by intensive agriculture compared to those in more preserved habitats, such as forests. This finding indicates that current agricultural practices may be contributing to the decline of species that were once thought to be resilient to farming activities. The decline of amphibian populations is not a new concern. Previous studies have highlighted the potential threats that agrochemicals pose to non-target organisms like amphibians. Sulfonylurea herbicides, for instance, have been shown to increase developmental duration and malformations in Bufo spinosus embryos, as well as alter their oxidative status[2]. Similarly, glyphosate's primary metabolite, AMPA, has been found to affect embryonic development and oxidative balance in amphibians[3]. Moreover, endocrine-disrupting actions of agrochemicals have been found to potentially impair amphibians' growth and reproduction by disrupting their metabolic processes[4]. These disruptions can have lasting effects on amphibian populations, affecting important life stages such as metamorphosis and sexual development. Furthermore, a study on the common toad (Bufo bufo) demonstrated that amphibians do not solely inhabit forested areas but are also present in agricultural landscapes where they are at risk of pesticide exposure[5]. This exposure could contribute to the decline of amphibian populations in these areas. The current study builds upon these earlier findings by directly linking the decline of a terrestrial amphibian population to the intensity of surrounding agricultural activities. While the exact factors causing this decline are yet to be identified, the study suggests that modern farming practices, likely including the use of agrochemicals, are having a more detrimental effect on amphibian populations than previously understood. The research conducted by CNRS-La Rochelle Université used a gradient of habitats to assess the spined toad's presence and abundance. This approach allowed the scientists to compare the species' population trends in different environments, from preserved forests to highly agricultural sites. The stark contrast in toad populations between these environments underscores the importance of habitat quality for the survival of amphibian species. The methods used in this study and the alarming results it produced call for further research to pinpoint the specific factors contributing to the decline of the spined toad in farmlands. Identifying these factors is critical for developing conservation strategies that can mitigate the effects of agricultural practices on biodiversity. In conclusion, the study by CNRS-La Rochelle Université not only adds to the growing body of evidence that modern agriculture is a threat to amphibian biodiversity but also emphasizes the urgency of investigating the current factors causing rapid declines in species previously considered tolerant to agricultural landscapes. As we continue to witness unprecedented rates of biodiversity loss, understanding and mitigating the impacts of human activities on wildlife becomes ever more crucial.



Main Study

1) Population declines of a widespread amphibian in agricultural landscapes.

Published 18th March, 2024


Related Studies

2) Nicosulfuron, a sulfonylurea herbicide, alters embryonic development and oxidative status of hatchlings at environmental concentrations in an amphibian species.


3) Aminomethylphosphonic acid (AMPA) alters oxidative status during embryonic development in an amphibian species.


4) Agrochemicals disrupt multiple endocrine axes in amphibians.


5) Potential pesticide exposure during the post-breeding migration of the common toad (Bufo bufo) in a vineyard dominated landscape.


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