Noord-Brabant on high alert for invasive American bullfrog; One found in Valkenswaard
Noord-Brabant is on high alert for the American bullfrog after a nature club discovered one of these invasive exotics in a small pond south of Valkenswaard. “The bullfrog is a plague for the entire native ecosystem. As a province, we have to protect the latter,” Hagar Roijackers of the Noord-Brabant provincial council told AD.
Like most invasive species, the American bullfrog has no natural enemies in the Netherlands. At the same time, they prey on many naturally occurring animals. “They eat our own green frogs, salamanders, and spread diseases and fungi that can affect all kinds of native species,” Jeroen van Delft of the reptile agency Ravon told the newspaper.
“At most, perhaps only a handful of frogs have crossed the border now, but if you let them have their way, there will be a thousand next year,” Van Delft said. The focus is, therefore, now entirely on nipping the spread of the American bullfrog in the bud.
The province is working with the Belgian government on eDNA research, testing water samples from fens, ditches, ponds, and other bodies of water for signs of the frog. “With this, you can detect a larva in a body of water as large as an Olympic swimming pool. That makes the search a bit easier.”
If researchers come across traces of the frog, they scan the surrounding area for possible spread and then decide how to respond. “By catching the larvae with traps or nets, or by shooting adult frogs with shotgun pellets. If it is safe to do so, we drain a pond, and then you can easily catch the frogs,” Van Delft said.
When asked why the province is going all out against the American bull frog while it scaled down its fight against the Asian hornet last year, Roijackers told AD: “We have to make choices and can only use our invasive species budget once. The fight against the bullfrog can still be won, but the one against the hornet cannot.”
