Mark Collins, Chair, the Broads Society
It’s all too easy to overlook familiar habitats and species that are actually very rare and
important in the wider world. For example, those of us lucky enough to visit or drive around
the Broads regularly will often see a Marsh Harrier soaring across a reedbed and perhaps
think little of it. But little more than 50 years ago, in 1971, after years of persecution and
habitat loss, only one nesting female remained in the whole country! It took decades of
conservation effort to build up the Broads as a centre for breeding pairs to thrive once again.
Some very rare ecosystems also have their heartland in Norfolk and the Broads, for example
carr woodland. Dominated by alder, sallow and birch trees, with guelder rose, buckthorn, dog
rose and brambles in the understorey, carr is an impenetrable, wet and shady wilderness
with dense trees and an abundance of ferns, fungi, mosses, lichens and liverworts. It has
increased in the Broads by a third in the past 50 years, perhaps principally due to climate
change and reduced commercial management of reedbeds but is little-known elsewhere in
Britain.
A habitat that lies mainly outside the wetlands of the Broads protected landscape but is vital
to its ecology is chalk streams. Surprisingly, three-quarters of the world’s 210 classified chalk
rivers and streams are to be found in England, and about 10% of them are in Norfolk. In the
UK we have our own more detailed classification that lists 224 of them, 58 of which are in
East Anglia, making our region important for this very rare habitat, both globally and
nationally.
Map: Chalk streams and rivers of Norfolk
They arise from springs in landscapes on chalk bedrock, where rainwater permeates quickly
into the soil rather than flowing across the surface and taking sediment with it. This explains
why chalk rivers and streams are generally beautifully clear, pure, and rich in freshwater
plants and fish, such as Brown Trout, that spawn in the gravelly riverbeds.
Most chalk streams flow through an agricultural landscape and few fall under legal
protection. Many are over-abstracted by water companies, causing weak flow, ecological
damage and ingress of sewage, while others have suffered from poor bankside
management, canalisation, invasive species and loss of biodiversity. Important chalk rivers in
Norfolk include the Bure, Glaven, Stiffkey, Burn, Heacham and Gaywood, but the longest,
biggest and most significant is the River Wensum, which forms a vitally important corridor
helping wildlife to move through the county and into the Broads.
The Brown Trout, an iconic denizen of chalk streams. Picture Credit Linda Pitkin.
The Wensum Catchment Partnership has supported the Norfolk Rivers Trust in a highly
successful citizen science project to sample, monitor and analyse the Wensum and its
tributaries. The river faces a number of challenges, including phosphate and nitrate pollution,
sediment run-off, sewage pollution, and, in some stretches, invasive species and physical
modification. Identifying the source of the problems and restoring the health of the river and
its wider catchment is the main priority, but in the absence of protection and effective
planning controls over much of its length, the task is not easy but is being achieved by
CaSTCo, the Catchment Systems Thinking Cooperative, which is a volunteer force set up to
work alongside professionals in monitoring and restoring our rivers.
The Wildlife Trusts, supported by many local councillors, are calling for the Government to
stand up for chalk rivers and streams in reforms of their National Planning Policy Framework
by introducing specific legal protections to protect these precious habitats from development-
related harm. Specifically, they have set up a petition to parliament calling for the
government to clarify its plan for chalk streams by releasing an improved version of the
previously promised ‘Chalk Stream Recovery Pack’. To be successful, this action plan needs
to enhance legal protections for chalk streams, strengthen enforcement mechanisms and
invest in restoration and conservation.
The River Glaven, a chalk river in Norfolk. Picture credit River Glaven Conservation Group.
The 2023 Levelling Up and Regeneration Act calls on all planning authorities, councils and
businesses actively to further the objectives of the Broads protected landscape. Chalk
streams and rivers may be impacted by developments far outside the boundaries of the
Broads but will adversely affect the integrity and biodiversity of the Broads as these
waterways wend their way into the rivers and lakes downstream.
In an earlier blog ‘Are Our Broadland Waterways Healthy?’ we reported the Campaign for
National Parks findings that only 39% of rivers and 15% of lakes in English National Parks
and the Broads are ecologically healthy enough for fish, invertebrates and plants to
thrive. Wetlands such as fens and marshes in the alluvial river valleys of the Bure, Yare and
Waveney, and the chalk river headwaters of the Wensum and Bure, support some of the
highest concentrations of freshwater Species of Conservation Concern to be seen anywhere
in England. Chalk streams and rivers need better protection so that the Broads themselves
can thrive.
Comments