Science News · Science

Yosemite Toads Contract Deadly Fungus During Winter Underground

Young Yosemite toads are emerging from their first winter with infections of the chytrid fungus Batrachochytrium dendrobatidis (Bd), a finding that suggests their winter burrows may pose a significant risk.

The chytrid fungus, which attacks amphibians' skin and can cause heart failure, has been linked to declines in hundreds of amphibian species. Yosemite toads, listed as threatened, spend about half the year underground in a hibernation-like state called brumation.

Researchers collected skin swabs from Yosemite toads of various ages in Yosemite National Park. They found that Bd was more common in juvenile toads after their first winter than in adult toads.

While about 23 percent of juveniles tested positive for Bd before brumation, over 90 percent emerged with infections after their first winter. In contrast, less than half of breeding adults tested positive.

It remains unclear how the waterborne fungus persists underground or why it appears to affect young toads more severely after brumation. Potential explanations include the growth of undetectable infections or transmission when toads burrow together.

The study also raises questions about whether other hibernating amphibians face similar risks. However, the findings have already influenced conservation efforts, with a reintroduction program now prioritizing the release of older toads that have passed their most vulnerable years.

AI-samenvatting op basis van de bron.