Hidden in the greenery: pool frog under pressure in a sea of lookalikes
In a new research report, INBO describes the current occurrence and genetic health of the pool frog in Flanders. The pool frog is the smallest of the three species of green frog found in our region.
This European protected species is no longer found in several of its historical habitats. Where the pool frog still occurs, invasive marsh frogs from various parts of Europe and the Near East threaten its survival. The native edible frog, a cross between the pool frog and the marsh frog, is also under pressure as a result.
In natural mixed populations with edible frogs, the proportion of pool frogs has declined significantly over the past twenty years. The proportion of invasive marsh frogs, on the other hand, has increased in relation to the other species of green frogs.
Pool frogs are often seen as a typical species of nutrient-poor habitats. However, we find important strongholds in nutrient-rich water systems, such as in the isolated metapopulations in the IJzer Valley and the wider area around Damme. These West Flemish populations also stand out for their high genetic diversity. This is in clear contrast to the populations in Limburg and especially Antwerp.
Although the habitat requirements of the various species of green frogs largely overlap, our research results underline the importance of temporary, often rather small water bodies in open landscapes in order to favor the protected pool frog over the other species.
Jeroen Speybroeck, Caroline Mouton, Karen Cox & Loïc van Doorn
Image above: pool frog (photo by Jeroen Speybroeck)