England’s chalk streams are a globally rare and valuable commodity. Their crystal clear waters, high levels of biodiversity, beautiful landscapes and abundance of fish stocks make them special and iconic. However, due to the fragility of such ecosystems and their sensitivity to environmental change, a multitude of pressures threaten their continuation. In particular it is urbanisation, overpopulation and hence an increasing demand for water and water-side land which threatens chalk streams making their conservation a long-standing conflict of interests. However, many charities, trusts and initiative work to reduce the impacts of these key threats and to educate stream users in sustainable methods.
Where are they found?
The south and east contain the majority of England’s chalk streams for example in Dorset, Hampshire, Wiltshire, Kent, Norfolk, south Cambridgeshire and Hertfordshire with additional streams found on the wolds in Lincolnshire and Yorkshire.
Why are they important?
Of the 200 chalk streams in the world, 85% of these are found in England as much of our lowland geology is comprised of chalk. This combined with our climate has lead to particularly high and specialised biodiversity, specific to these English landscapes. Chalk streams originate from groundwater aquifers, freshwater springs arising from surrounding chalk hills. Mildly acidic rainwater percolates through the chalk (and downstream gravel beds) leading to particularly clear, alkaline streams, perfect for invertebrates, such as rare species like the fine-lined pea mussel and a range of mayfly species, as well as for damselflies such as the Southern damselfly.
In turn, the abundance of insects in a pristine chalk stream provides the perfect food stuff for fish species such as brown trout, Atlantic salmon and brook lamprey, while the well vegetated banks and channels provide fish with shelter from predators. Other key species that live along our chalk streams are the otter, water vole, kingfisher, water shrew and white-clawed crayfish.
Chalk streams also have characteristic plant communities, many of which can be seen in the channel- for example river water crowfoot and starworts, with plants such as watercress and lesser water-parsnip along the margins. These plants and the crystal clear waters make chalk streams the most beautiful and iconic of all our rivers.
What are the key threats?
Of the 85% of global chalk streams that are found in England, only 25% of our chalk streams are of good status. This is primarily due to legacy damage such as impoundment of waterways for milling and agricultural irrigation, creating barriers to fish movement. Diffuse pollution originating on agricultural land in the form of fertiliser run-off or animal waste plus management of springs and nearby still waters for fish farming or growing of watercress can also pose a risk to the purity of our chalk streams. Fertilisers and herbicides particularly risk vegetation levels, either leading to algal blooms and eutrophication or killing off important native species respectively. Additionally, abstraction of water for modern irrigation and drinking water reduces levels and thus intensifies pollution levels within the stream. The problems of abstraction are so acute in some areas that some chalk streams have virtually disappeared such as The River Beane, which runs south past Stevenage to join the River Lea at Hertford.
The work of UK Wildlife Trusts
The UK’s Wildlife Trusts have been working in partnership with Natural England, The Environment Agency and many other partners and local communities to restore our chalk streams to good health and conserve the few areas of good status. One of their most successful schemes, the ‘Chalk streams Charter, was launched in May 2013 after a summit in Hampshire. The Charter calls for a range of measures to help tackle the problems, including designation of additional chalk streams as ‘Special Areas of Conservation’, greater consideration of water resource issues in relation to planning decisions on new developments, water metering, a national education campaign to reduce water demand and more restoration works along chalk streams to increase their connectivity and enable them to function naturally.
The Charter also supports a growing campaign to ask Government to intervene to support this kind of work with stronger policies that protect this important resource for people and wildlife. This is supported by parallel work by other Wildlife Trusts in delivering practical action such as new catchment management plans for the Rivers Beane and Mimram, launched in January 2013, and the Living Rivers project working in partnership with statutory agencies, environmental charities, local landowners, community organisations and river groups to deliver enhancements to chalk stream habitats
At home in Hampshire and on the Isle of Wight Wildlife, the Trust runs a Southern Chalkstreams Project, which works with land and river owners and managers to encourage habitat enhancement through sympathetic and beneficial management of rivers and the adjacent land and has focused on improving habitats for two key species- the southern damselfly and white clawed crayfish. In 2013 the Hampshire & Isle of Wight Wildlife Trust supported the Salmon & Trout Association’s complaint to the EU on the failure of the UK Government to comply with the Habitats Directive This complaint focuses on the Government‘s failure to adequately address the issues affecting the River Avon SAC.
The Wildlife Trusts will continue to work with the Environment Agency, Natural England, local communities and other partners to deliver practical improvements for our chalk streams and the special species they support. The practical work must go hand in hand with Government action to address the underlying problems of abstraction and pollution. The Government has a responsibility under the European Water Framework Directive and the Habitats Directive to play its part and to reverse the decline of chalk stream habitats and species.
A Manifesto for Chalk Streams
Alongside other initiatives and agencies, The Wildlife Trusts are leading the way in protecting and restoring one of the UK’s most iconic habitats. Increasing support and recent data offer glimmers of progress, with positive advances in policy and public engagement. Foremost, an action plan has been produced and recognised to safeguard our chalk streams and restore them to good health using the five following backbone ideas:
- Reduce abstraction
- Decrease pollution
- Revive natural river processes
- Improve habitat
- Promote better river management.
However isolated attempts at such improvements are not big enough, widespread enough or implemented fast enough to make a real difference to all of our chalk streams. We therefore need to promote a greater and more critical shift in conserving chalk streams using previous progress to power future accomplishments.