Cornwall Wildlife Trust has issued a warning that moving frog spawn from pond to pond can cause serious damage to nature.
As Cornwall Wildlife Trust Information Co-ordinator, Nic Harrison-White explains: “When transferring spawn to another location you will inevitably carry other organisms with it – which may include diseases and invasive exotic plants.”
He adds: “A number of Trust nature reserves have already been affected by introduction of problem pond plants such a parrot’s feather and Australian swamp stonecrop, which are impossible – or very expensive – to control. When these plants enter the countryside they can cause significant damage by choking up ponds, waterways and drainage systems leading to flooding and often smothering our native flora. We believe they often get there through ‘donations’ of spawn.”
Each year, the Trust receives many calls from householders who say they have ‘too much spawn’ in their garden ponds – but Nic is quick to point out that this is a misunderstanding.
“Amphibians have evolved a strategy of laying huge numbers of eggs. This is because just about every animal in a pond eats tadpoles! By producing such a lot of spawn, frogs ensure that at least some will grow into froglets. Competition between tadpoles that escape the predators helps keep the population under control, with only the fittest tadpoles surviving.”
While most people are fond of frogs, Cornwall Wildlife Trust does occasionally receive requests for advice on getting rid of them and their spawn.
“It’s a pity not everyone appreciates these creatures and the vital role they play in nature – as food for other wildlife an as controllers of pests,” says Nic. “If they are determined to reduce the number of frogs in their ponds, the safest option – for nature – is to take out the newly laid spawn and put it on the garden compost heap for wildlife to eat. ”
For those who want to increase frog numbers, the Trust’s advice is to create extra ponds – of all sizes – and wait for the frogs to arrive.
“Even if you know of no other ponds in your area, it’s surprising how quickly frogs will find you,” Nic advises.
For information on how to create and manage a wildlife-friendly pond, contact Nic Harrison-White on the Trust’s Wildlife Information Service on 01872 273939 ext 213.
If you are concerned that you may have harmful invasive plants see the ERCCIS website for information about the POND CHECK project or contact Lisa Rennocks on 01872 273939 ext 242 to find out how to prevent them spreading into the countryside.
