Norfolk’s rich pond heritage gets new lease of life
PUBLISHED: 11:20 18 February 2012
Restoring overgrown and neglected ponds could transform the Norfolk countryside and achieve major wildlife and diversity improvements, according to a leading ecologist.
Norfolk has one of the highest densities of field ponds in Britain with a total number estimated at between 25,000 and 30,000, Dr Carl Sayer told members of Holt & District Farmers’ Club.
He said ponds, which were often in the middle of arable fields, were a very rich and potential centre of natural biodiversity – for plants, amphibians, fish and predators, but had been allowed to become overgrown and neglected.
Dr Sayer surprised his 40-strong audience when he revealed that there were 22 field ponds within 1km of Bodham Church in the parish where his father, Derek farmed.
Norfolk had a rich heritage of ponds, partly because of the huge number of marl pits. “They originated about the 13th century when they were dug for marl [calcareous clay]which was spread over the fields in an early version of liming to make soils more productive. It peaked in the late 1700s and early 1800s but ended during the first world war. It has left a fantastic legacy of ponds,” said Dr Sayer, of University College London.
Although many had been lost to general agricultural improvements, when shielded from run-off from surrounding fields and managed with care, they were an incredibly rich wildlife reservoir, he said.
Some of ponds, including many close to Holt, support two-thirds of all the 80 aquatic species which are native to the UK. North Norfolk was also nationally important for the thriving populations of creatures including rare species of damselfly and especially great-crested newts.
Dr Sayer had become fascinated by Britain’s native Crucian carp, which was against all the odds, thriving in some parts of North Norfolk. As a youngster, it had been the very first fish that he had caught.
Today, he was determined to reverse the 75pc decline in the population of this native British species, which had happened in the past half century.
Dr Sayer said that a survey in the 1960s and 1970s found the species in about 50 ponds – now it is down to just 13 ponds in North Norfolk.
When the Environment Agency suggested that it had become extinct in Norfolk in 2008, it fired his enthusiasm. “It is known to be virtually the toughest fish in the world and can live for months without oxygen. It is an amazingly tough fish and likes small weedy ponds, ideally without any fish species.”
Dr Sayer said that the Crucian carp was now a biodiversity action species. “We’re restoring ponds for Crucian carp and will reintroduce into suitable ponds. We’ve just started this as a long-term project and have made three introductions of species to different ponds. We’re started bringing the species back from the brink,” he added.
On one farm near Holt, which had about 40 ponds, the results of positive management had been amazing. “Over the past few years, we’ve recorded 90 species of dragonfly, 50 water beetles, 25 species of water plants and great crested newts all over the place. The ponds are managed by rotation because every three or four years, the farmer manages them – by taking trees around the edge and letting more light into the pond.”
One over-grown pond on his father’s Bodham farm had been brought back to life. “It is an incredible diversity resource,” he said. “One with 80pc shade had no plants, three invertebrates, no fish, one toad but another pond had 14 plant species, 25 invertebrates, 10 different dragon flies, one fish, and a lot of British amphibian species. A tale of two ponds,” said Dr Sayer.