Suction solution for no-cut root route

In June 2017, Anglian Water began work on a pipeline renewal scheme at Belstead Water Tower, Ipswich. Trenching 1.2m deep by 0.5m wide was required to allow pipe-laying, but the only route out of the compound was in the Root Protection Area (RPA) of large oak, an important group of TPO trees.

Norfolk Wildlife Services worked with Anglian Water and Conroys to create an Arboricultural Method Statement [AMS].   An innovative solution  practical  technology –  a suction excavator [Conroy Vac Ex] – to prevent need to cut roots with ground protection techniques to protect tree roots of the protected trees from vehicle damage.

The suction excavator removes the soil around the roots, eliminating the need to cut through them in order to create the trench.  Major roots were left intact which means the trees ability to take up water and nutrients was not compromised.  Exposed roots were wrapped with wet hessian to prevent desiccation.  The pipe was then laid underneath the routes and the trench was then backfilled with the original soil, minimising disruption to the trees’ water supply in a period of dry weather.

Ground protection techniques help prevent compaction of the soil around the tree roots

 

Work begins on suction excavation of trench around tree roots using Conroy Vac Ex

Work with Conroy Vac Ex suction excavator continues on open trench and tree roots

 

Wet hessian bags were wrapped around the roots to avoid desiccation.

 

Pipe laying commences

 

 

 

Licencing Spotlight: Water voles

Water voles, their breeding sites and resting places are fully protected by law under Schedule 5 of the Wildlife and Countryside Act 1981, making it a criminal offence to injure, damage or disturb them. They like soft-shored banks for burrowing, wide swathes of soft vegetation growing from the banks and water and slow-flowing and relatively deep water courses.

vole

Water vole: Photo courtesy of Ann Roberts

Surveys of a development site for water voles are required if either:

  • Known local distribution and historical records suggest their presence
  • There is suitable habitat for water voles in or adjacent to it.

After these surveys we assess the impacts a development would have on water voles without mitigation measures . This can be used to support any relevant planning application or discussions with the drainage board or Environment Agency.

In most cases, you could avoid harming water voles by adjusting your planned work. If you can’t  and will damage their habitats, you may need a licence from Natural England. Some displacement activity can be done under a class licence by a registered person; other activities will require a site-specific licence.

A licence will be required if development would need to displace water voles or if trapping and translocation is necessary. Any licence application needs to show an overall net conservation benefit for the water voles. For example, increasing the amount of habitat available to water vole population and/or improving the quality of habitat.

We can advise you on delivering water vole mitigation and licencing and anything else water vole related, please contact the NWS team: office@norfolkwildlifeservices.co.uk

Invertebrate survey successes for Cley Marshes

coastal lagoon

Ben Christie sampling lagoonal invertebrates

FOLLOW-UP SURVEY ON TRUST’S NEW COASTAL LAND REVEALS IMPORTANT INVERTEBRATES

Our follow-up survey on Norfolk Wildlife Trust’s new marsh at Cley has found five invertebrate species of conservation importance, including lagoon sand shrimp Gammarus insensibilis (legally protected) and mud snail Ecrobia ventrosa.

The Trust commissioned a specialist baseline study on their new land at Cley Marshes when they purchased it in 2014. This was surveying the plants and invertebrates in the site’s ditches, dykes and scrapes.

Since then, the Trust has carried out extensive work on the marsh to convert it from wildfowling ponds to a nature reserve and wanted to repeat the surveys. The plan was to compare with the 2014 baseline and identify any changes resulting from the work.

Twelve sample ditches and lagoons sites from the 2014 survey were re-surveyed for aquatic invertebrates, following the same methodology. For each, we took two dip-net samples to collect a crosssection of the aquatic invertebrates in the water: one in underwater vegetation near the shore; and one reaching out into the depths of the open water.

Ben Christie, our invert specialist said: “By first grouping inverts into taxonomic orders and then using specialist microscope keys for identification, we were able to efficiently identify the specialist communities for every sample site. This allowed both a direct comparison of communities in 2014 and 17, but also showed distributions for five invertebrate species of conservation importance.

“Norfolk Wildlife Trust can now fully assess the benefits of their management on invertebrates as well as the birds and other wildlife who are dependent on them in the food chain.”

 

 

Summer bat surveys

The bat survey season is well and truly underway and at NWS surveys are taking place almost every day of the week. Initial surveys are undertaken to look for evidence of bats and if found then a minimum of three nocturnal surveys (dawn and dusk) may be required during the main survey season, i.e. May to September.

During a dusk survey, surveyors watch the building from 15 minutes before dusk and 2 hours after dusk to watch for any bats emerging from the building. A bat detector and a recording device are used to record any bat calls which are then analysed to confirm the sightings and to identify species. Target notes are also recorded on a map so any points of entry can be identified.

During a dawn survey, surveyors watch the building for the 2 hours before dawn (which means a very early start!). The same method is used as in a dusk survey but the surveyors are mainly watching for bats to return to roost.

These surveys can be really interesting and exciting if there is lots of activity at the site but they can also be a bit boring if there isn’t much going on (you are essentially staring at a building for 2 hours…. potentially at 2.30am!). It can be worth getting up super early though if you get a close encounter with a bat like at a recent site where Brown Long-eared bats were roosting just above our heads in a barn.

Brown long-eared bat

Brown long-eared bat

Mitigating for great crested newts

Since starting great crested newt surveys in mid-March 2015, about 20% of the 75 ponds surveyed across Norfolk contained newts. For these sites, their development may now require a “European Protected Species Mitigation” ( EPSM ) licence, granted by Natural England after planning permission is given.

Lemonade and great crested newts

Bottle Trap

Bottle trap used in great crested newt surveys

We devise the mitigation strategy for clients based on where and how many newts are present.

To estimate numbers, we make six nocturnal counts via netting, with “bottle traps” (1.5 litre lemonade bottles) and spotlights. This indication of population size is used to devise a proportional strategy, ensuring that your development does not adversely affect newt populations.

Compensatory habitat

The EPSM licence needs to provide “compensatory habitat” at least equal in extent to that lost by development.  Newt habitats include scrub, grassland and woodland, but also often brown field areas, especially near old gravel or brick pits.  Ideas to think about when designing “compensatory habitat” are:

  • Restoring existing ponds to make them more suitable for great crested newts by clearing out shading scrub or desilting.
  • Creating brand new ponds: often also an attractive landscape feature (but no fish please and balancing lagoons aren’t suitable!)
  • Making wildflower meadows: good foraging habitat for newts plus an attractive feature managed well;
  • Planting woodland belts and hedgerows makes excellent shaded habitat for newts with leaf litter and logs, plus good for site landscaping, and corridors for newts to travel along to safely get from one area to another.

The bucket stage

If work cannot avoid impacting great crested newts, the development will need fencing off and trapping out with “pitfall traps” (buckets) to capture them and move them to safety.   Trapping normally takes place in autumn or early spring as it requires both suitably wet weather, but reasonable temperatures for the newt activity.

The number of nights trapping depends on the population, varying between 30 and 90 nights with additional needs where breeding ponds are removed.  If the fencing fails during building, then retrapping may be required, so investment in a decent spec fence is worth some thought. Generally you will need to keep the perimeter up from start to finish.

To create the compensatory habitat for a site near Dereham, we cleared ornamental shrubs and seeded the bare banks with wetland wildflowers around an existing pond, creating excellent refuges and invertebrates to hunt. Enclaves of wildflowers and trees were connected via thick hedgerows running around the boundary of the development, linking to hedges and ponds in the landscape.  Post development, the 2015 recount of newts showed numbers of breeding newts have remained consistent at 85, and that the mitigation had been successful.

Creating a bespoke boudoir for bats

As part of the re-development of a small brownfield site within Norwich, NWS were commissioned by RGW Portugal Ltd to undertake bat surveys of two small buildings. One of these was found to support low numbers of brown long-eared bats Plecotus auritus and soprano pipistrelles Pipistrellus pygmaeus, which were using the building for roosting in summer. The buildings needed to be demolished in order to create space for two new residential homes, and so NWS prepared a European Protected Species Mitigation licence for bats which was granted by Natural England.

Brown long-eared bat captured during demolition work

Brown long-eared bat captured during demolition work

NWS licensed ecologists supervised the demolition of the buildings in August, removing a roosting brown long-eared bat which was found along the central ridge beam and relocating this within a bat box which had been placed on a mature oak tree in adjacent woodland.

RGW Portugal Ltd were keen for an environmentally sensitive development and had included bike stores within the design to encourage the use of green transport. These features provided the perfect opportunity to create a bespoke bat loft for both species of bats to use. The loft was constructed above the bike stores, using a lined and tiled pitched roof to generate warm internal temperatures. Two carefully-placed bat access points were installed along the ridge and at both gable ends, allowing a number of entry points whilst reducing potential for light ingress and draughts. The ridge beam was formed using rough-sawn timber to create a suitable surface for bats to cling to, and bat batons were also installed along the inner walls to provide additional perching points.

The last features of the bat loft have just been installed this winter and NWS are hopeful to see use of this loft by bats when they return to roost in April.

 

Getting stuck in the mud at Cley

With support from members, business and the Heritage Lottery Fund, Norfolk Wildlife Trust acquired 60 hectares of land at NWT Cley Marshes in 2014. Norfolk Wildlife Services carried out baseline studies of the plants and invertebrates with particular focus on the impacts of the January 2014 flooding on the site’s ecology.

We decided to get stuck into the project (literally) to survey the saline lagoons and freshwater dykes across the site for aquatic plants such as Phragmites australis, and aquatic invertebrates such as the water boatman Arctocorisa garmari.  Initial results showed that an increased proportion of the open water on the site was unsurprisingly either brackish or saline. The effect on invertebrate species was evident during surveying as several groups were under-represented such as dragonflies.

In early summer 2015, we will survey the terrestrial invertebrates when they are most active. Some of the terrestrial invertebrates sought for include the Red Data Book ground beetle Pogonus luridipennis, or more commonly found cross spider Araneus diadematus.  Invertebrates like these are key indicators of the habitat quality and conditions present.

NWS will be running a workshop in September next year, looking at how the invertebrate population at Cley supports birds such as bittern, avocet and godwit. Check our website for more details on this “Bittern’s Breakfast and Avocets Lunch” event.

New winter homes for great crested newts

Since 2000, NWS has worked on development sites that support great crested newts, and in 2014 successfully assisted Saffron Housing in obtaining a European Protected Species Mitigation (EPSM) licence for this species on a residential development in South Norfolk. Nationally great crested newts have suffered huge declines and so are protected by European and UK law. Norfolk is one of the species’ strongholds, with greatest numbers of breeding ponds found on heavy clay soils.

With great crested newts present in ponds around the area and using the grassland on site to move between these, the EPSM licence was required during construction to protect these amphibians and provide compensatory habitat.

NWS staff supervised the installation of “newt exclusion fencing” and carried out pitfall trapping to remove newts from harm’s way. Great crested newts only use ponds for breeding and spend the rest of the year on land. The team focussed the compensatory habitat on features suitable for use during this “terrestrial phase” and supervised the creation of what was dubbed “Newt Nirvana” by the developer:  a wildflower grassland with hedgerows and scrub.

A key feature was the creation of three earth and stone mounds, which newts will use

This hibernacula has a rubble/log base to provide crevices for overwintering newts

This hibernacula has a rubble/log base to provide crevices for overwintering newts and is covered with turf to create stable temperatures through winter

during winter, called hibernacula. Great crested newts hibernate when winter temperatures drop below 5oC, normally from October or November. They typically hibernate underneath logs, within mammal burrow or tree roots, and even in building foundations. The hibernacula on site were designed to provide a number of sheltered crevices using logs and rubble, topped with turf to prevent exposure, whilst also ensuring newts were safe from flooding. Here the newts can remain protected until they emerge in late February or March to begin breeding in ponds.

Invasive Non-Native Species – Japanese Knotweed – successful control

Our team are trained to recognise Invasive Non-Native Species [ also called INNS ]  on survey sites and advise on issues with their control.

One of the most pernicious, we encounter is Japanese Knotweed, which is an Asian species originating as a garden escape, spread via root fragments of its rhizomes, often from fly tipping or contaminated topsoil. Once established the underground rhizomes, Continue reading

Landscape design completed for Cley Marshes education centre

At Cley Marshes, Norfolk Wildlife Services are working with Norfolk Wildlife Trust on the new Simon Aspinall Wildlife Education Centre. Simon Aspinall was a naturalist who made important contributions to ornithology and conservation, and the new centre will reflect his love of nature, wildlife and education.

After extensive consultation and review of a number of landscape designs, the team has gained planning approval from North Norfolk District Council for a planting scheme around the centre, which will encourage butterflies and wildlife to the site and enrich the visitors’ experience.

Maritime turf and shingle planting will create formal “garden” areas, while new trees and shrub planting, using species and structure to match existing landscape elements, will ensure that the new building will blend into the surrounds and appear coherent with the existing centre.

NWT Project Manager, Ian Leatherbarrow, commented, “Norfolk Wildlife Services prompt response to developing an attractive, cost effective landscape design means that we can start work on the project knowing that the outdoor element of the work will be successfully delivered.”

Norfolk Wildlife Trust is one of our key clients; we work closely with them on many of their reserves. Other successful outcomes for the Trust include: transformation of land at Upton Broad and marshes from arable to grazing marsh and assisting with the development of Hilgay and Methwold as a wetland Living Landscape.