Teufelsgraben: Bund Naturschutz warns of amphibian extinction - "Number vanishingly small"

Newts and toads are threatened with extinction in the Devil's Trench. This is the result of this year's amphibian migration. The Bund Naturschutz now wants to concentrate on Sufferloh.

Holzkirchen – As soon as it gets warmer at night, frogs, toads, newts and salamanders migrate back to their spawning grounds in spring. In the county, volunteers help with their buckets to ensure that the amphibians arrive safely across the street. "But things don't look good for the amphibians in the Devil's Trench," says Helmut Schneider. He coordinates the amphibian protection project of the Holzkirchen local group of the Bund Naturschutz (BN). "If it snows so little again next year and the summer is dry, I don't know where the amphibians will spawn."

In the spring, his team of 20 helpers helped the migratory amphibians in the Teufelsgraben and Sufferloh across the road. Over a period of four to five weeks, the team documented exactly which and how many animals were rescued on the way to their spawning grounds.

Balance Devil's Ditch

Their record for the Devil's Trench is bitter: Since the beginning of the amphibian protection campaign in 1998, never before have so few amphibians been detected as this year - only 485 specimens, 40.25 percent less than in 2022. The number of mountain newts and pond newts halved, and the helpers recorded a drop of 39.7 percent in the case of common toads: 393 were counted – in 2016 there were almost ten times as many.

Already in 2022, the BN counted only 774 migratory amphibians, around 35.6 percent fewer than in 2021. Schneider attributes the rapid decline to the fact that the two spawning waters fed by the Hackenseebach in the Teufelsgraben have dried up – as has the Hackenseebach itself over a considerable distance. And this despite the fact that this year it rained several times in the months of March and April and occasionally snowed.

According to the observations of the Holzkirchen amphibian conservationists, the situation has been coming to a head since 2016. Since then, the meadow south of state road 2073 has been less and less sufficiently flooded during the snowmelt. However, the meltwater is necessary because it feeds the spawning waters through a drainage pipe under the road. A few dry summers followed, so that in 2019, for the first time, the spawning waters in the Teufelsgraben only had intermittent water.

As a result, the spawn often dried out before the tadpoles could develop. As a result, the amphibian offspring have been increasingly absent for years. In 2021, the situation improved in the short term, but the results of the past two counts show that the long-term trend is unlikely to be stopped. Disappointing for the conservationists who have been looking after the area for 25 years.

Consequences

The development has consequences for the amphibian conservation project: "There is no future in the Devil's Trench," says Schneider. He sees two scenarios for the amphibians there: "Either they migrate to other areas where they can still spawn, or the amphibian population in the Teufelsgraben area comes to a complete standstill in the near future."

For the first time, the BN local group did not erect a fence for the return migration – also in favor of the protection project in Sufferloh. "Their number has become vanishingly small in recent years," he says. In the past, 600 to 1400 females migrated back every year during the mating season. "This year it was basically zero." The result of years of development, the cause of which the BN clearly states: "There are clear consequences of climate change," says Schneider. In the long run, it is no longer justifiable to provide helpers in the Devil's Ditch for six weeks.

Balance Sheet Sufferloh

In Sufferloh, on the other hand, where there was a second protective fence for returning amphibians for the first time, the population has increased: 1920 amphibians, almost exclusively toads, were helped by the team there across the road – an increase of 31 percent compared to 2022. ever

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