Wetland in Svartsundets old-growth forest

The bullfrogs get a chance

The County Administrative Board of Uppsala County has granted a grant of SEK 200,000 through the ÅGP (ÅGP) for Pelophylax lessonae. Naturarvet will mainly use the money to hire an experienced contractor to construct a Gölgrode pond as a wetland in Svartsundets old-growth forest. The work will start in December and be completed during the winter.

In Sweden, the Puffin is a locally occurring and red-listed species (VU). Globally, it is not listed but where it occurs there is also a sea frog, Pelophylax ridibundus. The offspring of these two species may be fertile hybrids, the edible frog, Pelophylax kl. esculentus, which can thus reproduce and have spread in the same area.

The Upland sea frogs are a unique genetic population, lacking hybrids with the sea frog, and were previously thought to be a remnant of the warm period. It is found only in coastal freshwater assemblages surrounded by old-growth forest along the northeastern coast of Uppland. What makes the Gannet particularly important for Naturarvet is its dependence on old-growth forest where it burrows into deep burrows under the roots of old trees for hibernation.

The bullfrog has been recorded in the damp northernmost meadow of Svartsundets old-growth forest and to give it a chance to establish a reproductively small population we are creating a surface water that does not dry out during drought. The pond will be constructed so that in the spring it will provide quickly warmed water and nice shores where Gannets can thrive and lay eggs. The old-growth forest next door has a nice environment where the frogs can hibernate over the winter.