Herts Local Wildlife Sites Partnership newsletter March 2014

Registered in England: 816710 Registered Charity: 239863

The Hertfordshire Local Wildlife Sites Partnership does not necessarily identify with or hold themselves responsible for the views expressed by contributors, correspondents or advertisers.

Printed by Berforts on Revive White Silk made from 100% recycled fibre at a mill that has been awarded the ISO140001 certificate for environmental management. The pulp is bleached using a totally chlorine free (TCF) process.

Designed by Wildcat Design (wildcat1@ntlworld.com)

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March 2014

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Welcome...

...to the 2014 Local Wildlife Sites newsletter. This time we are focussing on river and wetland sites, management issues, ideas and opportunities.

We want to hear from you!

Comments or suggestions for future articles are welcome.

If you would prefer to receive your newsletter via email please contact Carol Lodge: carol.lodge@hmwt.org.

photo: HMWT/Rob Hopkins

Local Wildlife Sites (LWS) are sites of substantive nature conservation value and although they do not have any statutory status, many are equal in quality to statutory Sites of Special Scientific Interest (SSSIs).

There are more than 40,000 Local Sites in England overseen by 65 Local Sites systems, covering contrasting landscapes in coastal, rural and urban situations. Hertfordshire currently has 1,809 Local Wildlife Sites. Together with SSSIs, LWS support locally and nationally threatened species and habitats. They play a critical role in forming the building blocks of ecological networks and Living Landscapes.

What’s special about wetland Local Wildlife Sites?

Stocker’s Lake

The term ‘wetland’ covers a diverse range of habitats. Within Hertfordshire alone this includes rivers, streams, springs, water-cress beds, ponds, lakes, reservoirs, sewage works, fens, marshes, swamps, wet grassland and carr woodland. These wetlands are hugely important for both wildlife and people. Many of the wetlands of Hertfordshire, especially open waters, have been created by human activity, and all have been influenced by human activities to some degree.

In many cases this is due to the range of benefits they have provided – food, drinking water, power, transport and leisure opportunities as well as their natural purifying and flow regulating functions.

All types of wetland habitats – still or moving, support a myriad of species including specialist plants, rare and protected mammals such as water voles and otters, as well as many birds and invertebrates.

The majority of our wetlands are associated with the catchments of the River Lea and River Colne.

The Lea Catchment has recently been designated as a ‘Nature

Improvement Area’ where a partnership of organisations, landowners and individuals are working together to increase biodiversity. The Lower Lea Valley is of international importance to wildlife and has been designated as a ‘Special Protection Area and Ramsar Site’. In addition many wetlands in Hertfordshire are of national importance and have been designated as Sites of Special Scientific Interest. Many wetlands

photo: Alan Reynolds

01727 858901 info@hmwt.org www.hertswildlifetrust.org.uk

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Herts and Middlesex Wildlife Trust, Grebe House, St Michael’s Street, St Albans, AL3 4SN

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Registered address:

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n John Bryden, Technical Specialist (Biodiversity), Environment Agency

Herts and Middlesex

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We monitor four ecological groups in our rivers: invertebrates, plants, fish and diatoms (a basic algae).

Collected data is fed through computer software which rates the ecological results against target assemblages. These vary depending on environmental factors (i.e. size of channel, type of river, etc). If one of the groups meets ‘Good’ status, that waterbody meets LWS criteria. Note that WFD identify a waterbody reaching ‘Good’ status when all of the ecological groups reach ‘Good’ Status, while a LWS waterbody is designated when one of the groups reaches ‘Good’.

The Hertfordshire Local Wildlife Sites Partnership

What are Wildlife Sites?

The Wildlife Sites Partnership in Hertfordshire includes Herts and Middlesex Wildlife Trust, Hertfordshire Environmental Records Centre, Hertfordshire Ecology, Natural England, the Countryside Management Service, Lee Valley Regional Park Authority, Chilterns AONB, the Forestry Commission, FWAG and the Environment Agency, and is coordinated

by Herts and Middlesex Wildlife Trust.

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The Hertfordshire Local Wildlife Sites Partnership

The habitat criteria is based on the River Habitat Survey (RHS) www.river habitatsurvey.org, which scores the habitat of the river against two elements: Habitat Modification Score (HMS – how modified or artificial a section is) and Habitat Quality Assessment (HQA – how diverse the channel is). A section of river will qualify if it has a HMS of 1 or 2 (i.e. is near natural) AND a HQA of over 40 (i.e. has a number of significant positive features). These reaches will be designated over each RHS survey distance (500m) at a time. These reaches will not qualify if there is a

Ecological richness

HERTS LOCAL WILDLIFE SITES

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Bankside management work

Habitat criteria

CCI is a ‘Community Based Classification Scheme for freshwater macroinvertebrate populations’ developed

by R. Chadd and C. Extence (EA). It takes into account richness as well as rarity of the species present in macroinvertebrate data obtained from inland flowing and still water (UK) sites. The CCI provides an empirical basis for conservation initiatives, programmes and strategies, by producing a summary of aquatic invertebrate data over any appropriate scale of time and space. The final analysis can indicate exceptionally rich or regionally unusual invertebrate populations rather than focussing on nationally rare species. A CCI score of continuously over 10.1 will enable a site to be designated.

This newsletter has been produced by Herts and Middlesex Wildlife Trust on behalf of The Local Wildlife Sites Partnership, supported by funding from the Environment Agency, Herts County Council and North Herts District Council.

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n Cath Patrick Senior Conservation Officer at the Lee Valley Regional Park Authority (LVRPA)

This final element is aligned to the Water Framework Directive (WFD) assessment criteria. WFD is a European Directive which has been written into national legislation and aims to get all ‘waterbodies’ to ‘Good’ status.

CCI

The partnership

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ment options, which has proven useful in targeting management for the key features for the site. This winter we aim to undertake works on Stanstead Innings. These works will include: removal of trees along the lake banks to improve areas of the reedbed, removal of the scrub from the reedbeds which are known to be used by wintering bittern, tree works on selected fringes of the lake to improve the macrophyte population and the creation of an otter holt using the resulting logs.

The final surveys are due to be carried out in summer 2014 on other LWS including Admirals Walk Lake and Slipe Lane Pits.

For further information on this and any other works in Lee Valley Regional Park contact Cath Patrick. cpatrick@leevalleypark.org.uk For further information regarding visiting Lee Valley Park take a look at the website http://www.visitleevalley. org.uk/en/content/cms/nature/ nature-reserve/

significant low flow issue in nondrought conditions or significant water quality issues.

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by the Small River Lee. In 2011 selected trees were removed and pollarded from a very shaded section of river to encourage the growth of emergent vegetation, with the aim of extending the range of water voles found in the SSSI to the south.

Ongoing work is still needed to target the removal of non-native invasive species such as Himalayan balsam which can out-compete native vegetation. An improvement to the marginal vegetation is becoming evident. This winter work will be undertaken on a section of river to the north of this, continuing the expansion of suitable habitat further towards Silvermeade. This work is part-funded through the Lea Catchment Nature Improvement Area fund.

LVRPA has also been working with the Wildlife Trust on a three-year project to survey and assess the LVRPA-owned LWS to ensure that the information is up to date and that these sites are in Positive Conservation Management. The surveys are carried out by experienced surveyors and followed up with recommendations for enhancements and a site visit to discuss manage-

As the Environment Agency (EA) we collect a large amount of data to monitor the health of our rivers with a view to improving and restoring them. In 2010, the EA and the Herts Local Wildlife Sites Partnership refined the criteria for Riverine LWS using these significant data sets, to identify the most ecologically valuable rivers in Hertfordshire.

The Riverine LWS criteria can be split broadly into three elements: • Habitat value (geomorphology); • Rarity of species assemblage Community Conservation Index (CCI); • Ecological richness based on quality of groups of species against target scores for the type of riverine fish, invertebrates and macrophytes (plants).

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The network of waterways in the Lee Valley is hugely important for wetland mammals. Both water voles and otters have strongholds here.

However, without ongoing management waterways become overshadowed and habitat suitability deteriorates. The resulting decline in emergent vegetation can have a significant impact on the existing populations as well as their ability to move and increase their range throughout the catchment.

Survey work carried out in the Lee Valley, including the Lee Valley Wetland Mammal Assessment (2012), identified key hotspots for wetland mammals and habitat enhancement works undertaken. This includes work on Local Wildlife Sites (LWS) at Silvermeade, the Small River Lee in River Lee Country Park and Stanstead Innings, with further work planned for this winter.

Silvermeade (currently in Countryside Stewardship) is an area of riverside meadow intersected with a network of ditches and a hotspot for water voles. Some of these ditches had become choked with vegetation and works have been carried out to clear sections whilst maintaining a fringe of emergent vegetation. A number of mature trees have also been pollarded alongside a section of ditch to allow light to penetrate to the water, which will need to be repollarded on a fairly short rotation (compare the images above).

Work on hotspot areas is important. However, we also need to ensure that the linking habitats are maintained and enhanced to allow populations to move and expand.

The LWS at Thistly Marsh is bounded

...and before

photo: HMWT/Tim Hill

All photos: LVRPA

Lee Valley Park – working for wetland mammals Silvermeade – after ditch works

The criteria for Riverine Local Wildlife Sites

newsletter

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of county importance are classified as Local Wildlife Sites and their interest, conservation and management are the focus of this newsletter.

As an owner or manager of a Local Wildlife Site, you are contributing to conserving the biodiversity of Hertfordshire and the UK.

The Hertfordshire Local Wildlife Sites Partnership

Few people realise the global significance of Hertfordshire’s chalk rivers.

There are around 200 chalk streams in the world, with most found in the southeast UK, and a handful in northern France – nowhere else on Earth! Hertfordshire therefore has a significant proportion, with the Mimram, Beane, Rib, Ver, Ash and Gade, to name a few. They are beautiful and iconic ecosystems, supporting a wide range of native wildlife such as kingfishers, brown trout and water crowfoot. Chalk rivers also have a special place in our culture – they are the rivers of Constable, of Millais’ Ophelia, of Ratty and Mole.

Uniquely, chalk rivers get the vast majority of their flow from groundwater – which originally falls as rain and is then stored in the vast chalk aquifer beneath our feet. This water emerges at springs and feeds into the rivers. Because the water has been filtered through the chalk, it is clean, gin-clear, mineral-rich, and temperature-constant. These rivers are also characterised by a gravel bed, rich in-channel and bankside vegetation, low banks and a gently meandering form.

Chalk rivers are a feature of a number of Local Wildlife Sites, such as Singler’s Marsh, Archer’s Green and Panshanger Park along the Mimram, Waterford Marsh and Beane Marsh along the Beane, Sidehill Wood and Gingercress Farm

The work of the Countryside Management Service (CMS) frequently works to benefit Local Wildlife Sites (LWS) throughout Hertfordshire. Through our connection to sites owned by public bodies, and through partnership with organisations such as the Environment Agency (EA), over the past year we have implemented several projects on the county’s fragile chalk rivers, that will bring about significant improvements to

The Beane at Waterford post-restoration

Lack of water is one of the major problems facing chalk rivers such as the Mimram and Beane. However, deeperwater areas survive which become even more important during times of low flow.

Such areas need to be well managed in order to support the species which find refuge there. Together with the Environment Agency and other partners, the Wildlife Trust is undertaking some practical restoration projects to enhance existing river and bankside habitat. Such restoration projects will benefit individual stretches of river, but will also allow areas of good quality habitat to be linked together; these restored rivers will act as corridors, allowing wildlife to move through our landscapes.

n Charlie Bell Hertfordshire Living Rivers Officer, Herts and Middlesex Wildlife Trust

photo: CMS

Volunteers at work

some of the county’s globally rare chalk-river habitats.

The River Ver is one such river that has suffered over the years from damaging influences, including re-configuration and de-naturalisation of the channel, water abstraction, and the spread of non-native invasive species. These have resulted in a reduction of habitat diversity and quality, and the loss of native species, such as the white clawed crayfish and, in many watercourses, also the water vole. CMS has been leading a restoration project at Riverside Way, a linear public open space owned and managed by Hertfordshire County Council (HCC). The project has received funding and support from partners including Lafarge Aggregates and Concrete Ltd, EA and the Chilterns Chalk Streams Project, with further funding in 2014 from HCC and the District Council.

The project aims to restore the river’s ecosystem by increasing light levels to the channel, providing the right conditions for spawning fish,

Sopwell Nunnery. In-channel restoration and tree removal will commence here in early 2014.

In the east of the county a number of projects have been taking place

Digswell Lake’s water voles Digswell Lake is situated adjacent to the River Mimram north of Welwyn Garden City. This is now the only river flowing into Hertford with a significant water vole population. Due to the recent presence of mink near Codicote (now mostly caught), water vole populations were completely lost from the upper part of the river. However, downstream from Codicote, through Welwyn, Digswell, Tewinbury, Panshanger to Hertford, water vole populations survive.

Water voles ideally need unshaded low vegetation, with plentiful sedges, rushes and reeds, emerging from the water onto the bank. This provides

photo: Russell Spencer

photo: HMWT/Charlie Bell

photo: HMWT/Charlie Bell photo: HMWT/Tim Hill

River Mimram at Tewinbury

caused damage.

The Living Rivers project is a four year project which started in April 2012, funded by the Environment Agency and hosted by Herts and Middlesex Wildlife Trust. The overall aim of the project is broad: to help achieve landscape scale conservation in Hertfordshire’s river valleys, which makes perfect sense – rivers interconnect with each other and with the land (or ‘catchment’) which they drain.

Working with local landowners/ managers is crucial to the project’s success. Agricultural land covers a large proportion of Hertfordshire, and farmers can play a huge role in improving the health of our chalk rivers. Farming techniques can create real benefits for waterways on farmland. By fencing off the river for example, grazing animals are prevented from eroding long stretches of bank, which can result in large amounts of sediment entering the water. Fencing also prevents their urine and faeces from entering and polluting the channel directly. Creating vegetated ‘buffer strips’ between arable areas and rivers helps prevent chemicals from draining off agricultural land into nearby river channels. In addition, these buffer strips can also provide valuable habitat for insects and water voles.

As part of the Living Rivers project the Wildlife Trust is ‘hosting’ catchment management plans for six of Hertfordshire’s rivers.

Planning the management of a catchment is a huge task; no one person or group can do it alone. By hosting the plans, our role is one of facilitation and coordination; we are bringing together people and organisations with an interest in the river. This approach emphasises the importance of collaboration, and focuses on empowering local people as drivers to improving our rivers. The vision is for a management plan developed and implemented by a partnership of interested people/groups, including farmers, the local community, fishing clubs, landowners, charities and statutory bodies.

It’s an exciting (and challenging!) time to be working on Hertfordshire’s chalk rivers. I’m sure many of us treasure special memories of these places, whether or not we realised their global significance. For me, it’s the brown velvety back of my first water vole; for a lucky few, it might be the splash of an otter’s tail during a dive, or a bolt of blue from a speeding kingfisher. Rivers hold a special place in our hearts. I’m hopeful that, over the next few years, we’ll be able to see our chalk rivers changing for the better.

Waterford Marsh

within the Upper Lea Catchment, focussing on the River Beane. One such project has been underway at the Waterford Marsh LWS, just north of Hertford. This project, instigated by landowners Stapleford Parish Council, is being funded and supported

by HCC, EA, the Lea Catchment Nature Improvement Area and Network Rail. Over the next three years the project aims to improve public information, and enhance the site’s habitats by restoring an ordinary watercourse, improving damaged banks, pollarding willow trees, and creating shallow ponds.

Further downstream is Hartham Common (owned by East Herts District Council) where the Lee Navigation and the Rivers Beane, Rib and Lea, all converge. Management planning includes a Rivers Project, including access and interpretation.

CMS are also working with the council to establish a friends group for the site,

River Beane – dry near Whtehall Pumping Station

River Mimram at Poplars Green

Meadow along the Ash, Redbournbury and Sopwell Meadows along the Ver, and Great Gaddesden Pasture and Water End Meadows along the Gade.

Unfortunately they face numerous threats. Hertfordshire’s chalk rivers are classed as ‘over-abstracted’. The groundwater that feeds local rivers is a cheap and convenient source for our tap water with millions of litres pumped out each day, lowering the groundwater levels. Here in the southeast our water use is around 175 litres per person day, 18% above the national average and way above the government’s target of 130 litres per day. Every litre we save is an extra litre left for our rivers.

Pollution is another threat, whether from agricultural land, misconnections from domestic water pipes, sewer outflows or run-off from roads and urban areas. Invasive species such as American mink, signal crayfish and Himalayan balsam are having serious impacts on native plants and animals. Destruction of bankside habitat, via development, agriculture or mis-management, can destroy the homes and food sources of many species. Historic dredging, straightening, widening and canalisation have

providing slow flow silt deposit areas and creating vegetated refuges and river banks which allow shelter for several species. In addition, CMS and Ver Valley Society volunteers have been trained by the Wild Trout Trust to create deflecting structures in the river from debris, and will be continuing this over the next two years.

Other potential areas for enhancement have been identified along the River Ver, such as Verulamium Park and

photo: CMS

River projects benefit local wildlife sites

photo: HMWT/Charlie Bell

Hertfordshire’s chalk rivers

cover from predators, plenty of food and hidden access to burrows in the bank, and the opportunity to build nests above ground where banks are more shallow.

whose tasks will include the control of Himalayan balsam and scrub control on river banks.

Our ongoing conservation project at Purwell Meadows on the River Purwell in Hitchin progresses well.

Following fence installation and hedgerow restoration, cattle were back grazing the site over the summer and the meadows were alive with wild flowers and insects. New interpretation panels have been installed and tasks next year will include scrub management and Himalayan balsam removal.

CMS’ recent project work on river LWS focuses on the benefits both to people and wildlife. Rivers often provide the most accessible wildlife opportunities for visitors and walkers, and effective management provides a valuable link between nature and people.

n Tony Bradford, Head of the Countryside Management Service

Mink can eliminate entire water vole populations, simply by moving up and down the river. Should mink move along the Mimram through Digswell the effect could be devastating for water voles. However, because mink tend to follow the channel, Digswell Lake may be bypassed and become a refuge, from which vole recolonisation may occur once the mink have been caught. Individual LWS can play a vital role in the conservation of particular populations, but good connectivity within the broader landscape is essential for the long-term survival of water voles.

n Martin Ketcher Water Vole Conservation Officer, Herts and Middlesex Wildlife Trust

The Hertfordshire Local Wildlife Sites Partnership

Few people realise the global significance of Hertfordshire’s chalk rivers.

There are around 200 chalk streams in the world, with most found in the southeast UK, and a handful in northern France – nowhere else on Earth! Hertfordshire therefore has a significant proportion, with the Mimram, Beane, Rib, Ver, Ash and Gade, to name a few. They are beautiful and iconic ecosystems, supporting a wide range of native wildlife such as kingfishers, brown trout and water crowfoot. Chalk rivers also have a special place in our culture – they are the rivers of Constable, of Millais’ Ophelia, of Ratty and Mole.

Uniquely, chalk rivers get the vast majority of their flow from groundwater – which originally falls as rain and is then stored in the vast chalk aquifer beneath our feet. This water emerges at springs and feeds into the rivers. Because the water has been filtered through the chalk, it is clean, gin-clear, mineral-rich, and temperature-constant. These rivers are also characterised by a gravel bed, rich in-channel and bankside vegetation, low banks and a gently meandering form.

Chalk rivers are a feature of a number of Local Wildlife Sites, such as Singler’s Marsh, Archer’s Green and Panshanger Park along the Mimram, Waterford Marsh and Beane Marsh along the Beane, Sidehill Wood and Gingercress Farm

The work of the Countryside Management Service (CMS) frequently works to benefit Local Wildlife Sites (LWS) throughout Hertfordshire. Through our connection to sites owned by public bodies, and through partnership with organisations such as the Environment Agency (EA), over the past year we have implemented several projects on the county’s fragile chalk rivers, that will bring about significant improvements to

The Beane at Waterford post-restoration

Lack of water is one of the major problems facing chalk rivers such as the Mimram and Beane. However, deeperwater areas survive which become even more important during times of low flow.

Such areas need to be well managed in order to support the species which find refuge there. Together with the Environment Agency and other partners, the Wildlife Trust is undertaking some practical restoration projects to enhance existing river and bankside habitat. Such restoration projects will benefit individual stretches of river, but will also allow areas of good quality habitat to be linked together; these restored rivers will act as corridors, allowing wildlife to move through our landscapes.

n Charlie Bell Hertfordshire Living Rivers Officer, Herts and Middlesex Wildlife Trust

photo: CMS

Volunteers at work

some of the county’s globally rare chalk-river habitats.

The River Ver is one such river that has suffered over the years from damaging influences, including re-configuration and de-naturalisation of the channel, water abstraction, and the spread of non-native invasive species. These have resulted in a reduction of habitat diversity and quality, and the loss of native species, such as the white clawed crayfish and, in many watercourses, also the water vole. CMS has been leading a restoration project at Riverside Way, a linear public open space owned and managed by Hertfordshire County Council (HCC). The project has received funding and support from partners including Lafarge Aggregates and Concrete Ltd, EA and the Chilterns Chalk Streams Project, with further funding in 2014 from HCC and the District Council.

The project aims to restore the river’s ecosystem by increasing light levels to the channel, providing the right conditions for spawning fish,

Sopwell Nunnery. In-channel restoration and tree removal will commence here in early 2014.

In the east of the county a number of projects have been taking place

Digswell Lake’s water voles Digswell Lake is situated adjacent to the River Mimram north of Welwyn Garden City. This is now the only river flowing into Hertford with a significant water vole population. Due to the recent presence of mink near Codicote (now mostly caught), water vole populations were completely lost from the upper part of the river. However, downstream from Codicote, through Welwyn, Digswell, Tewinbury, Panshanger to Hertford, water vole populations survive.

Water voles ideally need unshaded low vegetation, with plentiful sedges, rushes and reeds, emerging from the water onto the bank. This provides

photo: Russell Spencer

photo: HMWT/Charlie Bell

photo: HMWT/Charlie Bell photo: HMWT/Tim Hill

River Mimram at Tewinbury

caused damage.

The Living Rivers project is a four year project which started in April 2012, funded by the Environment Agency and hosted by Herts and Middlesex Wildlife Trust. The overall aim of the project is broad: to help achieve landscape scale conservation in Hertfordshire’s river valleys, which makes perfect sense – rivers interconnect with each other and with the land (or ‘catchment’) which they drain.

Working with local landowners/ managers is crucial to the project’s success. Agricultural land covers a large proportion of Hertfordshire, and farmers can play a huge role in improving the health of our chalk rivers. Farming techniques can create real benefits for waterways on farmland. By fencing off the river for example, grazing animals are prevented from eroding long stretches of bank, which can result in large amounts of sediment entering the water. Fencing also prevents their urine and faeces from entering and polluting the channel directly. Creating vegetated ‘buffer strips’ between arable areas and rivers helps prevent chemicals from draining off agricultural land into nearby river channels. In addition, these buffer strips can also provide valuable habitat for insects and water voles.

As part of the Living Rivers project the Wildlife Trust is ‘hosting’ catchment management plans for six of Hertfordshire’s rivers.

Planning the management of a catchment is a huge task; no one person or group can do it alone. By hosting the plans, our role is one of facilitation and coordination; we are bringing together people and organisations with an interest in the river. This approach emphasises the importance of collaboration, and focuses on empowering local people as drivers to improving our rivers. The vision is for a management plan developed and implemented by a partnership of interested people/groups, including farmers, the local community, fishing clubs, landowners, charities and statutory bodies.

It’s an exciting (and challenging!) time to be working on Hertfordshire’s chalk rivers. I’m sure many of us treasure special memories of these places, whether or not we realised their global significance. For me, it’s the brown velvety back of my first water vole; for a lucky few, it might be the splash of an otter’s tail during a dive, or a bolt of blue from a speeding kingfisher. Rivers hold a special place in our hearts. I’m hopeful that, over the next few years, we’ll be able to see our chalk rivers changing for the better.

Waterford Marsh

within the Upper Lea Catchment, focussing on the River Beane. One such project has been underway at the Waterford Marsh LWS, just north of Hertford. This project, instigated by landowners Stapleford Parish Council, is being funded and supported

by HCC, EA, the Lea Catchment Nature Improvement Area and Network Rail. Over the next three years the project aims to improve public information, and enhance the site’s habitats by restoring an ordinary watercourse, improving damaged banks, pollarding willow trees, and creating shallow ponds.

Further downstream is Hartham Common (owned by East Herts District Council) where the Lee Navigation and the Rivers Beane, Rib and Lea, all converge. Management planning includes a Rivers Project, including access and interpretation.

CMS are also working with the council to establish a friends group for the site,

River Beane – dry near Whtehall Pumping Station

River Mimram at Poplars Green

Meadow along the Ash, Redbournbury and Sopwell Meadows along the Ver, and Great Gaddesden Pasture and Water End Meadows along the Gade.

Unfortunately they face numerous threats. Hertfordshire’s chalk rivers are classed as ‘over-abstracted’. The groundwater that feeds local rivers is a cheap and convenient source for our tap water with millions of litres pumped out each day, lowering the groundwater levels. Here in the southeast our water use is around 175 litres per person day, 18% above the national average and way above the government’s target of 130 litres per day. Every litre we save is an extra litre left for our rivers.

Pollution is another threat, whether from agricultural land, misconnections from domestic water pipes, sewer outflows or run-off from roads and urban areas. Invasive species such as American mink, signal crayfish and Himalayan balsam are having serious impacts on native plants and animals. Destruction of bankside habitat, via development, agriculture or mis-management, can destroy the homes and food sources of many species. Historic dredging, straightening, widening and canalisation have

providing slow flow silt deposit areas and creating vegetated refuges and river banks which allow shelter for several species. In addition, CMS and Ver Valley Society volunteers have been trained by the Wild Trout Trust to create deflecting structures in the river from debris, and will be continuing this over the next two years.

Other potential areas for enhancement have been identified along the River Ver, such as Verulamium Park and

photo: CMS

River projects benefit local wildlife sites

photo: HMWT/Charlie Bell

Hertfordshire’s chalk rivers

cover from predators, plenty of food and hidden access to burrows in the bank, and the opportunity to build nests above ground where banks are more shallow.

whose tasks will include the control of Himalayan balsam and scrub control on river banks.

Our ongoing conservation project at Purwell Meadows on the River Purwell in Hitchin progresses well.

Following fence installation and hedgerow restoration, cattle were back grazing the site over the summer and the meadows were alive with wild flowers and insects. New interpretation panels have been installed and tasks next year will include scrub management and Himalayan balsam removal.

CMS’ recent project work on river LWS focuses on the benefits both to people and wildlife. Rivers often provide the most accessible wildlife opportunities for visitors and walkers, and effective management provides a valuable link between nature and people.

n Tony Bradford, Head of the Countryside Management Service

Mink can eliminate entire water vole populations, simply by moving up and down the river. Should mink move along the Mimram through Digswell the effect could be devastating for water voles. However, because mink tend to follow the channel, Digswell Lake may be bypassed and become a refuge, from which vole recolonisation may occur once the mink have been caught. Individual LWS can play a vital role in the conservation of particular populations, but good connectivity within the broader landscape is essential for the long-term survival of water voles.

n Martin Ketcher Water Vole Conservation Officer, Herts and Middlesex Wildlife Trust

The Hertfordshire Local Wildlife Sites Partnership

Registered in England: 816710 Registered Charity: 239863

The Hertfordshire Local Wildlife Sites Partnership does not necessarily identify with or hold themselves responsible for the views expressed by contributors, correspondents or advertisers.

Printed by Berforts on Revive White Silk made from 100% recycled fibre at a mill that has been awarded the ISO140001 certificate for environmental management. The pulp is bleached using a totally chlorine free (TCF) process.

Designed by Wildcat Design (wildcat1@ntlworld.com)

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March 2014

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Welcome...

...to the 2014 Local Wildlife Sites newsletter. This time we are focussing on river and wetland sites, management issues, ideas and opportunities.

We want to hear from you!

Comments or suggestions for future articles are welcome.

If you would prefer to receive your newsletter via email please contact Carol Lodge: carol.lodge@hmwt.org.

photo: HMWT/Rob Hopkins

Local Wildlife Sites (LWS) are sites of substantive nature conservation value and although they do not have any statutory status, many are equal in quality to statutory Sites of Special Scientific Interest (SSSIs).

There are more than 40,000 Local Sites in England overseen by 65 Local Sites systems, covering contrasting landscapes in coastal, rural and urban situations. Hertfordshire currently has 1,809 Local Wildlife Sites. Together with SSSIs, LWS support locally and nationally threatened species and habitats. They play a critical role in forming the building blocks of ecological networks and Living Landscapes.

What’s special about wetland Local Wildlife Sites?

Stocker’s Lake

The term ‘wetland’ covers a diverse range of habitats. Within Hertfordshire alone this includes rivers, streams, springs, water-cress beds, ponds, lakes, reservoirs, sewage works, fens, marshes, swamps, wet grassland and carr woodland. These wetlands are hugely important for both wildlife and people. Many of the wetlands of Hertfordshire, especially open waters, have been created by human activity, and all have been influenced by human activities to some degree.

In many cases this is due to the range of benefits they have provided – food, drinking water, power, transport and leisure opportunities as well as their natural purifying and flow regulating functions.

All types of wetland habitats – still or moving, support a myriad of species including specialist plants, rare and protected mammals such as water voles and otters, as well as many birds and invertebrates.

The majority of our wetlands are associated with the catchments of the River Lea and River Colne.

The Lea Catchment has recently been designated as a ‘Nature

Improvement Area’ where a partnership of organisations, landowners and individuals are working together to increase biodiversity. The Lower Lea Valley is of international importance to wildlife and has been designated as a ‘Special Protection Area and Ramsar Site’. In addition many wetlands in Hertfordshire are of national importance and have been designated as Sites of Special Scientific Interest. Many wetlands

photo: Alan Reynolds

01727 858901 info@hmwt.org www.hertswildlifetrust.org.uk

H

Herts and Middlesex Wildlife Trust, Grebe House, St Michael’s Street, St Albans, AL3 4SN

THE

Registered address:

IP

n John Bryden, Technical Specialist (Biodiversity), Environment Agency

Herts and Middlesex

SH

We monitor four ecological groups in our rivers: invertebrates, plants, fish and diatoms (a basic algae).

Collected data is fed through computer software which rates the ecological results against target assemblages. These vary depending on environmental factors (i.e. size of channel, type of river, etc). If one of the groups meets ‘Good’ status, that waterbody meets LWS criteria. Note that WFD identify a waterbody reaching ‘Good’ status when all of the ecological groups reach ‘Good’ Status, while a LWS waterbody is designated when one of the groups reaches ‘Good’.

The Hertfordshire Local Wildlife Sites Partnership

What are Wildlife Sites?

The Wildlife Sites Partnership in Hertfordshire includes Herts and Middlesex Wildlife Trust, Hertfordshire Environmental Records Centre, Hertfordshire Ecology, Natural England, the Countryside Management Service, Lee Valley Regional Park Authority, Chilterns AONB, the Forestry Commission, FWAG and the Environment Agency, and is coordinated

by Herts and Middlesex Wildlife Trust.

R

The Hertfordshire Local Wildlife Sites Partnership

The habitat criteria is based on the River Habitat Survey (RHS) www.river habitatsurvey.org, which scores the habitat of the river against two elements: Habitat Modification Score (HMS – how modified or artificial a section is) and Habitat Quality Assessment (HQA – how diverse the channel is). A section of river will qualify if it has a HMS of 1 or 2 (i.e. is near natural) AND a HQA of over 40 (i.e. has a number of significant positive features). These reaches will be designated over each RHS survey distance (500m) at a time. These reaches will not qualify if there is a

Ecological richness

HERTS LOCAL WILDLIFE SITES

RE

Bankside management work

Habitat criteria

CCI is a ‘Community Based Classification Scheme for freshwater macroinvertebrate populations’ developed

by R. Chadd and C. Extence (EA). It takes into account richness as well as rarity of the species present in macroinvertebrate data obtained from inland flowing and still water (UK) sites. The CCI provides an empirical basis for conservation initiatives, programmes and strategies, by producing a summary of aquatic invertebrate data over any appropriate scale of time and space. The final analysis can indicate exceptionally rich or regionally unusual invertebrate populations rather than focussing on nationally rare species. A CCI score of continuously over 10.1 will enable a site to be designated.

This newsletter has been produced by Herts and Middlesex Wildlife Trust on behalf of The Local Wildlife Sites Partnership, supported by funding from the Environment Agency, Herts County Council and North Herts District Council.

DSHI

n Cath Patrick Senior Conservation Officer at the Lee Valley Regional Park Authority (LVRPA)

This final element is aligned to the Water Framework Directive (WFD) assessment criteria. WFD is a European Directive which has been written into national legislation and aims to get all ‘waterbodies’ to ‘Good’ status.

CCI

The partnership

FOR

ment options, which has proven useful in targeting management for the key features for the site. This winter we aim to undertake works on Stanstead Innings. These works will include: removal of trees along the lake banks to improve areas of the reedbed, removal of the scrub from the reedbeds which are known to be used by wintering bittern, tree works on selected fringes of the lake to improve the macrophyte population and the creation of an otter holt using the resulting logs.

The final surveys are due to be carried out in summer 2014 on other LWS including Admirals Walk Lake and Slipe Lane Pits.

For further information on this and any other works in Lee Valley Regional Park contact Cath Patrick. cpatrick@leevalleypark.org.uk For further information regarding visiting Lee Valley Park take a look at the website http://www.visitleevalley. org.uk/en/content/cms/nature/ nature-reserve/

significant low flow issue in nondrought conditions or significant water quality issues.

RT

by the Small River Lee. In 2011 selected trees were removed and pollarded from a very shaded section of river to encourage the growth of emergent vegetation, with the aim of extending the range of water voles found in the SSSI to the south.

Ongoing work is still needed to target the removal of non-native invasive species such as Himalayan balsam which can out-compete native vegetation. An improvement to the marginal vegetation is becoming evident. This winter work will be undertaken on a section of river to the north of this, continuing the expansion of suitable habitat further towards Silvermeade. This work is part-funded through the Lea Catchment Nature Improvement Area fund.

LVRPA has also been working with the Wildlife Trust on a three-year project to survey and assess the LVRPA-owned LWS to ensure that the information is up to date and that these sites are in Positive Conservation Management. The surveys are carried out by experienced surveyors and followed up with recommendations for enhancements and a site visit to discuss manage-

As the Environment Agency (EA) we collect a large amount of data to monitor the health of our rivers with a view to improving and restoring them. In 2010, the EA and the Herts Local Wildlife Sites Partnership refined the criteria for Riverine LWS using these significant data sets, to identify the most ecologically valuable rivers in Hertfordshire.

The Riverine LWS criteria can be split broadly into three elements: • Habitat value (geomorphology); • Rarity of species assemblage Community Conservation Index (CCI); • Ecological richness based on quality of groups of species against target scores for the type of riverine fish, invertebrates and macrophytes (plants).

??????????????

E

The network of waterways in the Lee Valley is hugely important for wetland mammals. Both water voles and otters have strongholds here.

However, without ongoing management waterways become overshadowed and habitat suitability deteriorates. The resulting decline in emergent vegetation can have a significant impact on the existing populations as well as their ability to move and increase their range throughout the catchment.

Survey work carried out in the Lee Valley, including the Lee Valley Wetland Mammal Assessment (2012), identified key hotspots for wetland mammals and habitat enhancement works undertaken. This includes work on Local Wildlife Sites (LWS) at Silvermeade, the Small River Lee in River Lee Country Park and Stanstead Innings, with further work planned for this winter.

Silvermeade (currently in Countryside Stewardship) is an area of riverside meadow intersected with a network of ditches and a hotspot for water voles. Some of these ditches had become choked with vegetation and works have been carried out to clear sections whilst maintaining a fringe of emergent vegetation. A number of mature trees have also been pollarded alongside a section of ditch to allow light to penetrate to the water, which will need to be repollarded on a fairly short rotation (compare the images above).

Work on hotspot areas is important. However, we also need to ensure that the linking habitats are maintained and enhanced to allow populations to move and expand.

The LWS at Thistly Marsh is bounded

...and before

photo: HMWT/Tim Hill

All photos: LVRPA

Lee Valley Park – working for wetland mammals Silvermeade – after ditch works

The criteria for Riverine Local Wildlife Sites

newsletter

Teal

of county importance are classified as Local Wildlife Sites and their interest, conservation and management are the focus of this newsletter.

As an owner or manager of a Local Wildlife Site, you are contributing to conserving the biodiversity of Hertfordshire and the UK.

The Hertfordshire Local Wildlife Sites Partnership

Registered in England: 816710 Registered Charity: 239863

The Hertfordshire Local Wildlife Sites Partnership does not necessarily identify with or hold themselves responsible for the views expressed by contributors, correspondents or advertisers.

Printed by Berforts on Revive White Silk made from 100% recycled fibre at a mill that has been awarded the ISO140001 certificate for environmental management. The pulp is bleached using a totally chlorine free (TCF) process.

Designed by Wildcat Design (wildcat1@ntlworld.com)

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March 2014

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WILDL

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Welcome...

...to the 2014 Local Wildlife Sites newsletter. This time we are focussing on river and wetland sites, management issues, ideas and opportunities.

We want to hear from you!

Comments or suggestions for future articles are welcome.

If you would prefer to receive your newsletter via email please contact Carol Lodge: carol.lodge@hmwt.org.

photo: HMWT/Rob Hopkins

Local Wildlife Sites (LWS) are sites of substantive nature conservation value and although they do not have any statutory status, many are equal in quality to statutory Sites of Special Scientific Interest (SSSIs).

There are more than 40,000 Local Sites in England overseen by 65 Local Sites systems, covering contrasting landscapes in coastal, rural and urban situations. Hertfordshire currently has 1,809 Local Wildlife Sites. Together with SSSIs, LWS support locally and nationally threatened species and habitats. They play a critical role in forming the building blocks of ecological networks and Living Landscapes.

What’s special about wetland Local Wildlife Sites?

Stocker’s Lake

The term ‘wetland’ covers a diverse range of habitats. Within Hertfordshire alone this includes rivers, streams, springs, water-cress beds, ponds, lakes, reservoirs, sewage works, fens, marshes, swamps, wet grassland and carr woodland. These wetlands are hugely important for both wildlife and people. Many of the wetlands of Hertfordshire, especially open waters, have been created by human activity, and all have been influenced by human activities to some degree.

In many cases this is due to the range of benefits they have provided – food, drinking water, power, transport and leisure opportunities as well as their natural purifying and flow regulating functions.

All types of wetland habitats – still or moving, support a myriad of species including specialist plants, rare and protected mammals such as water voles and otters, as well as many birds and invertebrates.

The majority of our wetlands are associated with the catchments of the River Lea and River Colne.

The Lea Catchment has recently been designated as a ‘Nature

Improvement Area’ where a partnership of organisations, landowners and individuals are working together to increase biodiversity. The Lower Lea Valley is of international importance to wildlife and has been designated as a ‘Special Protection Area and Ramsar Site’. In addition many wetlands in Hertfordshire are of national importance and have been designated as Sites of Special Scientific Interest. Many wetlands

photo: Alan Reynolds

01727 858901 info@hmwt.org www.hertswildlifetrust.org.uk

H

Herts and Middlesex Wildlife Trust, Grebe House, St Michael’s Street, St Albans, AL3 4SN

THE

Registered address:

IP

n John Bryden, Technical Specialist (Biodiversity), Environment Agency

Herts and Middlesex

SH

We monitor four ecological groups in our rivers: invertebrates, plants, fish and diatoms (a basic algae).

Collected data is fed through computer software which rates the ecological results against target assemblages. These vary depending on environmental factors (i.e. size of channel, type of river, etc). If one of the groups meets ‘Good’ status, that waterbody meets LWS criteria. Note that WFD identify a waterbody reaching ‘Good’ status when all of the ecological groups reach ‘Good’ Status, while a LWS waterbody is designated when one of the groups reaches ‘Good’.

The Hertfordshire Local Wildlife Sites Partnership

What are Wildlife Sites?

The Wildlife Sites Partnership in Hertfordshire includes Herts and Middlesex Wildlife Trust, Hertfordshire Environmental Records Centre, Hertfordshire Ecology, Natural England, the Countryside Management Service, Lee Valley Regional Park Authority, Chilterns AONB, the Forestry Commission, FWAG and the Environment Agency, and is coordinated

by Herts and Middlesex Wildlife Trust.

R

The Hertfordshire Local Wildlife Sites Partnership

The habitat criteria is based on the River Habitat Survey (RHS) www.river habitatsurvey.org, which scores the habitat of the river against two elements: Habitat Modification Score (HMS – how modified or artificial a section is) and Habitat Quality Assessment (HQA – how diverse the channel is). A section of river will qualify if it has a HMS of 1 or 2 (i.e. is near natural) AND a HQA of over 40 (i.e. has a number of significant positive features). These reaches will be designated over each RHS survey distance (500m) at a time. These reaches will not qualify if there is a

Ecological richness

HERTS LOCAL WILDLIFE SITES

RE

Bankside management work

Habitat criteria

CCI is a ‘Community Based Classification Scheme for freshwater macroinvertebrate populations’ developed

by R. Chadd and C. Extence (EA). It takes into account richness as well as rarity of the species present in macroinvertebrate data obtained from inland flowing and still water (UK) sites. The CCI provides an empirical basis for conservation initiatives, programmes and strategies, by producing a summary of aquatic invertebrate data over any appropriate scale of time and space. The final analysis can indicate exceptionally rich or regionally unusual invertebrate populations rather than focussing on nationally rare species. A CCI score of continuously over 10.1 will enable a site to be designated.

This newsletter has been produced by Herts and Middlesex Wildlife Trust on behalf of The Local Wildlife Sites Partnership, supported by funding from the Environment Agency, Herts County Council and North Herts District Council.

DSHI

n Cath Patrick Senior Conservation Officer at the Lee Valley Regional Park Authority (LVRPA)

This final element is aligned to the Water Framework Directive (WFD) assessment criteria. WFD is a European Directive which has been written into national legislation and aims to get all ‘waterbodies’ to ‘Good’ status.

CCI

The partnership

FOR

ment options, which has proven useful in targeting management for the key features for the site. This winter we aim to undertake works on Stanstead Innings. These works will include: removal of trees along the lake banks to improve areas of the reedbed, removal of the scrub from the reedbeds which are known to be used by wintering bittern, tree works on selected fringes of the lake to improve the macrophyte population and the creation of an otter holt using the resulting logs.

The final surveys are due to be carried out in summer 2014 on other LWS including Admirals Walk Lake and Slipe Lane Pits.

For further information on this and any other works in Lee Valley Regional Park contact Cath Patrick. cpatrick@leevalleypark.org.uk For further information regarding visiting Lee Valley Park take a look at the website http://www.visitleevalley. org.uk/en/content/cms/nature/ nature-reserve/

significant low flow issue in nondrought conditions or significant water quality issues.

RT

by the Small River Lee. In 2011 selected trees were removed and pollarded from a very shaded section of river to encourage the growth of emergent vegetation, with the aim of extending the range of water voles found in the SSSI to the south.

Ongoing work is still needed to target the removal of non-native invasive species such as Himalayan balsam which can out-compete native vegetation. An improvement to the marginal vegetation is becoming evident. This winter work will be undertaken on a section of river to the north of this, continuing the expansion of suitable habitat further towards Silvermeade. This work is part-funded through the Lea Catchment Nature Improvement Area fund.

LVRPA has also been working with the Wildlife Trust on a three-year project to survey and assess the LVRPA-owned LWS to ensure that the information is up to date and that these sites are in Positive Conservation Management. The surveys are carried out by experienced surveyors and followed up with recommendations for enhancements and a site visit to discuss manage-

As the Environment Agency (EA) we collect a large amount of data to monitor the health of our rivers with a view to improving and restoring them. In 2010, the EA and the Herts Local Wildlife Sites Partnership refined the criteria for Riverine LWS using these significant data sets, to identify the most ecologically valuable rivers in Hertfordshire.

The Riverine LWS criteria can be split broadly into three elements: • Habitat value (geomorphology); • Rarity of species assemblage Community Conservation Index (CCI); • Ecological richness based on quality of groups of species against target scores for the type of riverine fish, invertebrates and macrophytes (plants).

??????????????

E

The network of waterways in the Lee Valley is hugely important for wetland mammals. Both water voles and otters have strongholds here.

However, without ongoing management waterways become overshadowed and habitat suitability deteriorates. The resulting decline in emergent vegetation can have a significant impact on the existing populations as well as their ability to move and increase their range throughout the catchment.

Survey work carried out in the Lee Valley, including the Lee Valley Wetland Mammal Assessment (2012), identified key hotspots for wetland mammals and habitat enhancement works undertaken. This includes work on Local Wildlife Sites (LWS) at Silvermeade, the Small River Lee in River Lee Country Park and Stanstead Innings, with further work planned for this winter.

Silvermeade (currently in Countryside Stewardship) is an area of riverside meadow intersected with a network of ditches and a hotspot for water voles. Some of these ditches had become choked with vegetation and works have been carried out to clear sections whilst maintaining a fringe of emergent vegetation. A number of mature trees have also been pollarded alongside a section of ditch to allow light to penetrate to the water, which will need to be repollarded on a fairly short rotation (compare the images above).

Work on hotspot areas is important. However, we also need to ensure that the linking habitats are maintained and enhanced to allow populations to move and expand.

The LWS at Thistly Marsh is bounded

...and before

photo: HMWT/Tim Hill

All photos: LVRPA

Lee Valley Park – working for wetland mammals Silvermeade – after ditch works

The criteria for Riverine Local Wildlife Sites

newsletter

Teal

of county importance are classified as Local Wildlife Sites and their interest, conservation and management are the focus of this newsletter.

As an owner or manager of a Local Wildlife Site, you are contributing to conserving the biodiversity of Hertfordshire and the UK.

The Hertfordshire Local Wildlife Sites Partnership