Monday, 22 June 2015

Saving Private Natterjack

As I make my way over to the Natterjack toad pools the time is 9:06 and the sun is already beating down fiercely. The dry spell has been going on for months here at Hokham NNR and while the drying out of these shallow pools is an important part of Natterjack ecology if it happens too early it will kill the fragile tadpoles before they can undergo metamorphosis. Having taken measurements, I calculated that almost 400 litres of water is being evaporated from the ponds each day!

The Natterjack is also known as the ‘running toad’ as the 
short hind limbs allow it to run after prey rather than hop.

So with no rain in sight, it’s time for some drastic action! Today I have brought reinforcements. Using a borrowed 1000 litre water water Tank and a fair bit of ingenuity we intend to top up the pools over this dry spell. This is no easy feat as the topography of the reserve makes it very difficult for the water tank to get close enough to the slacks. As well as avoiding rabbit holes the water (1.5 tonnes) needs to flow downhill in a trickle, this enables warm water to enter the pools, if the water was too cold then the tadpoles would take longer to metamorphose and that would mean a likelihood of higher predation.

It was difficult finding a hosepipe long enough to reach
the ponds! 

Getting the water levels right is crucial for the Natterjack toads to breed successfully. Too much water could spell disaster because the tadpoles could be eaten by diving beetle and dragonfly larvae, too little and the ephemeral ponds will dry out before they have had chance to change.

Depending on the weather Natterjacks breed from 
April to June in Britain.

Why go to all this trouble I hear you ask? In the UK Natterjack populations are small, fragmented and threatened by habitat loss. They are also one of Britain’s rarest amphibians. Holkham NNR is one of only 60 sites in the UK where Natterjack toads can be found. It is therefore vital that we take action to help the Natterjack toads through the breeding season by preventing the ponds from drying out.

Natterjacks are described as being Europe's noisiest 
amphibian. On still, sunny evenings its chorus can be heard 
over several kilometres.

Be sure to check back in a couple of months to see how successful our rescue mission has been.

Please note
As a European protected species, under The Wildlife and Countryside Act 1981, schedule 2 and 5, it is an offence to capture, possess, disturb, kill, injure, or trade individuals of this species. It is also an offence to destroy the places they use for breeding or resting. Therefore we ask you to stick to the paths, tread carefully and enjoy listening to these charismatic noisy amphibians. Please do not go off to look for toads in the dunes, pools, and fields or enter any pools (including dogs) as this can cause disturbance.

Jonathan Holt