Salix provide the perfect habitat for water voles.
The Highways England £1.5bn A14 Cambridge to Huntingdon improvement scheme includes a major new bypass to the south of Huntingdon and upgrades to 21 miles of the A14.
This massive civils project (being delivered by the A14 Integrated Delivery Team – construction joint venture between Costain, Skanska & Balfour Beatty and design joint venture Atkins / CH2M) uncovered Roman Army camps and also Anglo Saxon settlements revealing surprising historical evidence of how densely populated it was in the past.
Current local inhabitants of the furry kind have also been found – water voles (Arvicola amphibius). This endangered species needed vital habitat mitigation works to be carried out in certain sections of the works in order to thrive. Water voles are the fastest declining mammal species within the UK and their main threats are habitat loss (leading to habitat fragmentation) and predation, in particular by the non-native American mink.
Within one section of the Scheme a new side road was to be constructed which had an impact on an existing watercourse, Covells Drain. Therefore, a new realignment channel of approximately 500 metres in length was constructed.
Once the vegetation had become established within the new channel, the water voles within the existing Covells Drain were trapped by licensed ecologists and temporarily held in captivity (for a few weeks) until the habitat from within the Covells Drain had been removed, ensuring that when the water voles were released into the new channel they would not return to their old habitat, but rather enjoy the newly established habitat.
In order to release the captured water voles in time, rapid habitat creation was required, on completely bare ground devoid of vegetation. The timeframe was very tight to create a mature wetland/riparian habitat, with works beginning at the end of June and the water voles needing to be released at the beginning of October. Therefore, standard planting and seeding was not an option.
Salix were brought in as a specialist contractor and supplier of wetland plants, pre-established Coir Rolls and Coir Pallets. Working with Julia Massey, an independent consultant and water vole specialist, coir pallets, consisting of mature wetland vegetation grown in-house at our nursery in Norfolk, were installed along the newly formed channel. We also installed pre-grown turf to speed up the process of establishment on the banks above the wetland margin.
This was essential for the water voles in order for them to find refuge within mature habitat and also have plenty of food source. They eat a large variety of grasses and waterside vegetation, with around 227 plant species identified in their diet, so they’re not overly fussy but they do seem quite partial to a bit of Coir grown Carex and Glyceria!
Julia Massey commented – Given the extremely tight time constraints it was essential that the vegetation that was installed was pre-established sufficiently to be able to release the water voles in October 2018. Salix were able to source the mature vegetation to enable the works to continue, which was fantastic. Salix were incredibly helpful, efficient and ready to rise to the challenge, as always. Thanks so much for all of your help.