Vernal pools are a surprising hub of biodiversity

Vernal pools house rich biodiversity and significant invertebrate activities. It is time to pay more attention to these overlooked environments.

Vernal pools are ephemeral pools that fill with water in the spring and autumn and dry during the summer. Because of their changing nature, they often get ignored as a significant home of biodiversity.

Researchers at the University of Helsinki studied ten vernal pools and ten permanent wetlands in the Evo Natura 2000 area in Finland. Many of the vernal pools were situated near the valuable esker habitats Syrjänalusen harju and Peikkovuori.

"We found that there was significantly higher bird activity in vernal pools than in permanent wetlands during the spring period. The study also revealed greater numbers of visits of elk (Alces alces), roe deer, and hares by vernal pools than by permanent wetlands," says Charly Dixneuf.

Furthermore, higher small mammal activity was detected in April by vernal pools compared to permanent wetlands. In contrast, during May and June this activity was significantly higher by permanent wetlands than by vernal pools.

"Threats to these pools are increasing because of the climate change, ditching practices, and forests drainages. More research investing more time and resources would help further investigate for example the microclimate, bird activity throughout the whole year, water cycle of the pool, and entire breeding period," Charly Dixneuf proposes.



Charly Dixneuf, Parami Peiris, Petri Nummi, Janne Sundell. Vernal pools enhance local vertebrate activity and diversity in a boreal landscape, Global Ecology and Conservation, Volume 31, 2021,