biodiversity crisis Archives

September 26, 2023

PFAS posing threat to wildlife, scientists say

Wildlife exposure to per- and poly-fluoroalkyl substances (PFAS) poses added added threats to species already struggling to adapt to habitat loss and harmful climate change, a new paper warns.

In a discussion paper published Tuesday in Science of the Total Environment, scientists wrote that there is enough evidence of the toxicity of persistent chemicals such as PFAS in humans to cause substantial concern about the same chemicals’ impacts on wildlife. Considering toxic chemicals’ health harms to wildlife is especially important, they write, as multiple pressures cause steep drops in biodiversity worldwide.

“There’s an incredible body of scientific evidence linking PFAS to health harms in humans, and this should really serve as an indicator of the potential health harms that may be occurring in wildlife globally,” said David Andrews, a co-author on the paper and a senior scientist at the Environmental Working Group (EWG), an environmental advocacy group.

PFAS are commonly used for their stain- and water-resistant properties and have been used for years as a common ingredient in firefighting foam and many household products. Almost all US residents have PFAS in their blood, and the chemicals contaminate water systems serving millions of people nationwide. PFAS are abundant in the natural environment, as well: According to one analysis by the Waterkeeper Alliance, over 80% of natural waterways are contaminated with the chemicals.

Toxic across taxa
There are thousands of types of PFAS, and scientists have found evidence that many can impair the immune system and spur developmental and reproductive problems, as well as cause thyroid and hormone disorders, liver problems, cancers, and nervous system effects.

“What we know [about health harms] in humans indicates that this is a threat to wildlife species globally,” said Andrews.

September 7, 2023

Amid steep global bird declines, farmers create refuges

New research finds that certain farming practices are benefiting some types of birds, underscoring the influence agriculture can have on important species at a time when bird populations around the world are in decline.

Farms that make use of smaller plots, varied crops, and tracts of forest, are helping boost bird populations in Costa Rica, scientists wrote in a paper published Monday in the Proceedings of the National Academy of Sciences. The findings add to previous evidence that diversified farming is an important conservation tool, said co-author and Stanford University researcher Nicholas Hendershot.

“There is a really huge benefit for biodiversity from these diversified farming practices,” he said.

Hendershot and his colleagues determined that over 18 years, bird species living on diversified Costa Rica farms were more likely than those in forests to have increasing, rather than decreasing populations. The varied crops and natural features on diversified farms provide a home for the birds and for insects and other animals that birds eat, said Hendershot.

On intensified farms, which generally plant only one crop and make use of high amounts of pesticides, the only species of birds thriving long-term were those that were adapted to highly-degraded landscapes, indicating the importance of diversified farms to provide habitat for other bird species, he said.