07.04.2021

Krkonoše frogs have started spring migration

• Venue: Krkonoše

The period of frog migration in the Giant Mountains has just begun, so drivers in particular should pay increased attention to these amphibians on the roads. The migration time is variable and very much depends on the weather, so it is not possible to determine its exact date. Warm and humid nights are optimal for frogs. Night wandering has a completely prosaic reason, which is the natural protection against predators.

There are six species of amphibians living in the Giant Mountains - the salamander, the newt, the newt, the great newt, the brown frog and the common toad. Some of them, such as toads and jumpers, move on land for most of the year, often far from the water. However, they need water to reproduce, because they lay eggs in it, from which tadpoles hatch. Many amphibians are tied to the same place of reproduction, the so-called spawning ground, throughout their lives. The trajectories remain largely the same for generations. If such a move crosses the road, amphibians do not change their target and fall victim to cars as they overcome the barrier. In the past, there were many such collision places, where amphibians died en masse during the spring migration, also in the Krkonoše and Podkrkonoší Mountains.

Temporary barriers protect frogs

Through the efforts of the KRNAP Administration, the vast majority of them were removed. In many places, therefore, temporary barriers are installed at this time - approximately 30 cm high strips of solid plastic, which are stretched in the most endangered areas. Frogs don't jump over them. On the contrary, thanks to them, it is possible to direct their movement and guide them into the prepared plastic buckets. These are transmitted in the morning and evening by the nature conservation guards of the KRNAP Administration and volunteers through critical sections.

However, the installation of temporary barriers is not the only way to effectively prevent losses when moving frogs to the spawning grounds. In recent years, the KRNAP administration has installed so-called permanent barriers in several places of intense frog migration. In some places you will also find the traffic sign "Attention, frog!".

Unlike temporary barriers, which are packed and stored for another year after the end of migration, permanent barriers remain installed all year round. These are approximately 30 cm high strips of sheet metal, which again direct the movement of the frogs. The longest section with permanent barriers is around the Elbe dam in Špindlerův Mlýn. According to the conservationists, it can be assumed that about two thousand frogs will be able to be transferred and saved.

An effective aid to amphibians is the creation or restoration of small bodies of water in which water is retained. Amphibians migrate here, especially during the breeding season. Such exemplary localities include ponds around Harrachov on the way to the Mumlavský waterfall.

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