Water Voles and their Habitat

Saltersley Common (Wilmslow)

Water Voles (Arvicola amphibius), History and Lifestyle

The water vole is often called a Water Rat. It is classified as a rodent along with voles, lemmings and muskrats.

The water vole weighs between 140-350gms and is the largest British vole species. The male is larger than the female. It is vole like in form with a blunt muzzle and short round ears which are almost hidden in its thick fur coat. As it's name suggests it is well adapted to a watery environment but it is not a good swimmer as it does not have webbed feet. It seeks a damp habitat along clean flowing waterways set in deep vegetated banks.

Water voles were formerly common throughout the British Isles but the population has declined rapidly over the last 100 years, due to varying factors. On Saltersley Common (a.k.a. Lindow Moss) it has been caused by habitat destruction, mainly due to the de-watering of their habitat. They primarily feed on stems and leaves of waterside plants and their best habitat is highly layered bank-side vegetation. A broad luxuriant fringe of waterside vegetation is essential for Water Voles.

Water Voles live in burrows between 40mm to 80mm in diameter with many nest and food storage areas plus bolt holes. These occur at various levels above the water in steep banks. They tend to live in colonies along the length up to 300 meters of a water course.

The females can produce up to 3 litters, the young being generally born between April and September. The life expectancy of an adult female is on average 1 year or less, the male is about 2 years.

Biota Report

Cheshire County Council instructed Croghan Peat Industries Ltd, the then leaseholders of the site, to carry out a Water Vole survey. Biota were instructed to undertake this work in 2005 and the final report was prepared in April 2006, this was forwarded to Cheshire County Council. In the Biota report it was stated in Paragraph 9 that 3 kilometres of ditch was suitable for Water Vole occupation and that these should be fully managed: 'it is important that the drainage channels are maintained in the long term and not allowed to vegetate over. A programme of a 5 year rotational management of the ditch system (WV-2) Plan A'.

In the report it stated;'prior to the cleaning of the ditches the water voles should be discouraged from using the area by damming the ditch and the extraction of the water from the area to be managed. The vegetation is also to be strimmed at a height of approximately 25mm prior to the damming of the ditch. This will discourage the water vole from using the area until the vegetation is cleared. Once the vegetation has been cleared the ditch system should be reopened. No two adjacent areas are to be managed in consecutive years. A weed bucket is to be used when cleaning out the ditches.'

The ditch system on the site which connects the main refugia areas (both around the perimeter and through the site) should be managed to act as a corridor for future colonisation by the water voles as the land was taken out of peat extraction. These ditches will require regular maintenance but wherever possible will be managed on one bank only unless or otherwise agreed by the County Ecologist or in an emergency.

The approximate length of these ditches to be managed for water voles would be 3 kilometres (approx 40% of the ditch length on the site)

Saltersley Common Preservation Society commissioned Mr. Derek Gow of the Derek Gow Consultancy Ltd (specializing in Water Voles) to do a survey of the peat bog. He could not identify this work as being undertaken. In addition permission was given by Mr. Brookfield (Planning Enforcement Officer for Cheshire County Council) for Ditch B to be significantly lowered to allow drainage for the drying out of the peat to assist with the harvesting. This is despite it being the only ditch where a water vole was sighted in the Biota report 18 months previously. At the time he was advised of this when he attended the site.

Reasons for the decline of Water Voles

It is the belief of Derek Gow Consultancy Ltd that the principal reasons for the decline of the water vole on Saltersley Common are:

• The lowering of the site water table by artificial drainage through the peat workings to a stage where most of the former and current ditch systems no longer retain water.

• The removal of all or most of the acceptable riparian vegetation within the ditch systems which contain water to the stage where no substantial amount of permanent food or cover vegetation is retained.

• The provision of no visible programme of habitat enhancement which would adequately allow the survival of the water vole population on the site.

It is clear that the central issue confronting the survival of the water vole population on Saltersley Common is generated by the sites management for peat extraction. This process has decisively lowered the water table on the site by a programme of significant drainage which has seen the systematic elimination of water vole habitat. It has continued to degrade the habitat that water voles required as given by it's own management advice (Biota Water Vole Survey 2006). The initial Biota calculation of 1.5 kilometres of suitable habitat may have been accurate at that time, but is certainly less today.

Future Habitat Re-management

Only a tiny population of water voles now exists on Saltersley Common. The main elements for successful re-management to rebuild the population should be:

1. The cessation of the complete vegetation removal from the ditch system. If clearance is necessary then this should be undertaken by using a long reach digger to clear the central channel without touching the bank side or crushing the neighbouring burrows. This is only to be undertaken in February and March when the population is inactive.

2. The bankside vegetation must be allowed to re-establish to a width 5 metres on each side wherever possible. With the exception of scrub clearance this should form an exclusion zone from commercial activity. As peat extraction ceases, the worked areas in the wider environment should be re-profiled to create a series of pools retained by bunds at their lower end which would form a complex of artificial meres allowing further expansion of the water vole population.

3. The creation of higher water levels on the site through the installation of a sluice at the lower end of Sugar Brook as contained in Condition 12 of the planning consent. This feature must be sufficient to retain the maximum water depth now possible in the main stream system.

4. The coppicing of the deciduous scrub cover on the ditch edges.

5. The installation of sheet metal piling at the end of all higher ditch systems to retain reliable depths of water in the summer months. This system should be designed to ensure complete habitat linkage throughout the site. This will allow establishment of linked water vole colonies and enable individuals to move through a good habitat pool to pool.

Conclusion

The Cheshire Wildlife Trust has undertaken water vole surveys throughout the North West Lowlands of England. A survey was undertaken by them on Lindow Moss which identified surviving populations of water voles on Saltersley Common and Lindow Common in 2009. These two colonies are believed to be the two most significant in East Cheshire and as such are locally very important. The Saltersley Common population has considerably reduced since the Biota report in 2006 and it has reached this condition as a direct result of the peat extraction which has systematically destroyed it's environment.

Water Voles are a strictly protected series under Schedule 5 in the Wildlife and Countryside Act (1981), where it is a criminal offence to kill or maim the creatures or to harm or destruct their habitat. The responsibility to ensure their survival must rest with the site operators but more so with the former Cheshire County Council (now Cheshire East Council) who had a statutory authority to act to prevent the destruction of the water vole population.

ENDS