3 February 2012

Icy Pond Advice

With temperatures outside dropping, ice becomes a common feature – making gardens glisten and turning ponds and water features into mini ice rinks. But do you need to worry about it? Froglife’s Conservation Communications Officer Lucy Benyon explains.

“Some common frogs choose to spend the winter at the bottom of ponds and the formation of a layer of ice can be a problem. Buried down amongst the mud and silt, they survive by breathing through their skin but when ice forms the frogs become trapped with limited oxygen and various noxious gases building up.

It can be very difficult to try and protect the amphibians in your pond over the winter. The frogs, and occasionally newts, that choose to overwinter in the pond risk becoming trapped if ice forms and, sadly, it’s natural for a few to die. To minimise deaths from ‘winterkill’ try to clear fallen snow from the ice, so that light can still reach the plants in the pond and they can continue to produce oxygen. If you have a pump, leaving this running throughout the winter can also help.
Frozen ponds: gases under the ice can cause a problem for amphibians
In the past, Froglife has always recommended that a hole is maintained in the ice but recent reports suggest this may not make any difference to the frogs’ survival and in some situations, when the ice becomes very thick, it’s simply not possible.

If you can make a hole it certainly won’t do any harm. Try leaving something floating in the water which can be removed to leave a hole once the ice forms. Alternatively stand a pan of hot water on top to melt one. Never pour the hot water on or try to smash the ice as this can be damaging.
A saucepan of hot water can gently melt a hole
Despite your best efforts it may be that you still lose some frogs over this wintry period. You will see them floating under the ice or rising to the surface once the ice has melted. Although this is not nice to see, it is quite natural for frog populations to suffer losses at this time of year and it should not have too much overall impact.

Fortunately the majority of amphibians will be tucked up in other corners of the garden – under logs or in compost heaps – and should suffer no ill effects from the winter weather.

To help hibernating amphibians, and reptiles, in your garden in future ensure there are plenty of hidey holes such as rockeries and log piles. It’s also a good idea to give your pond a bit of a clear out in the autumn and stock up on oxygenating weed.”

- You can find more advice on ponds in Froglife's Just Add Water publication here.
- Take part in the Pond Conservation Big Pond Thaw Survey 2011/12 here
You can also help support amphibians and reptiles by shopping with Froglife here.  We have some great gifts for wildlife-friendly valentines!

Photos: Lucy Benyon & Jules Howard

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