Cassiobury Park LNR and Whippendell Wood SSSI are owned and managed by Watford Borough Council who are working in partnership with the Trust to improve their value for wildlife and people. The partnership is working in consultation with a range of stakeholders to involve the local community, support volunteering and enable people to care for and enjoy these special places. 

Whilst Cassiobury Park Nature Reserve might be in the midst of urbanisation it is a wetland wonderland, with its mosaic of chalk river, ponds, wet woodland and natural springs. Here, we demonstrate some of the ways we are working with Watford Borough Council and volunteer work parties to deliver the management plan objectives on site.

Maintaining open areas of water

Within the nature reserve are old Watercress beds, some of which are raked on rotation, in sections to provide a diversity of habitats along the channel, with areas of aquatic vegetation in different stages of growth and pockets of open water with clean gravel beds. These open areas of water support birds such as Kingfishers,, Little Egrets and Grey Herons, as well as many aquatic invertebrates. The Watercress beds are spring-fed from the underground aquifer which ensures a near constant temperature year-round. Even during harsh cold snaps the water does not freeze, providing a valuable resource for aquatic birds.

Letting nature rule

Wet woodland is a rare habitat in Hertfordshire but one that exists in this nature reserve so preserving and maintaining it is of great importance. The way we do this is through non-intervention – in other words we let nature take its course, allowing trees such as Alder (Alnus glutinosa) to reach maturity until they eventually become standing deadwood. This forms prime habitat for the Lesser Spotted Woodpecker  – rare in Hertfordshire but occasionally recorded here.

Letting in light

Recently our team have been working in the sedgebeds, pollarding and coppicing Willows to prevent natural succession to woodland. These areas of sedge add to the habitat diversity found on the reserve and, along with the areas of reed on site, provide habitat for bird species such as Sedge Warblers .

In the northern part of the reserve, there are five ponds and, with the help of volunteers, we coppice the surrounding Willows on rotation to prevent the build-up of leaf-litter and allow light to reach the water, encouraging the growth of aquatic vegetation which is important for a variety of species, such as dragonflies and damselflies. Our pond work also supports the Great Crested Newts and Smooth Newts , who dwell here.

Controlling and eradicating invasive species

Himalayan Balsam is an invasive non-native species which spreads vigorously, shading out other vegetation, thus impoverishing native flora alongside river and canal banks. Himalayan Balsam-pulling work parties on the reserve have been instrumental in the success of progression towards its eradication at Cassiobury Park.

Looking after our precious chalk rivers

The Trust are working with Community Connections, a not-for-profit organisation, which undertakes land and river management projects in Watford. Together with the help of volunteers, we have been Willow spiling within the reserve to create a natural barrier at areas of bank erosion along the River Gade to stabilise the bank and discourage dogs running into the water and further eroding the riverbanks.

Benefitting bats

As a result of the careful management of the reserve’s wetlands, bat habitat can be found in abundance - from open woodland glades teaming with insects to dead-standing wood providing roosting opportunities. The Daubenton’s Bat is associated with wetlands and can be found at Cassiobury Park taking advantage of the accumulation of insects such as mayflies dancing above the water’s surface at dusk throughout the warmer months. Keep an eye on our events page for Bat Walks this summer and experience the feeding frenzy for yourself!

Habitat improvement to benefit endangered species

Water Voles could once be found at Cassiobury Park, and although habitat is suitable for their return, a number of factors currently stand in their way. The nearest population can be found just one mile away but a weir is preventing their passage. The Trust is working with the Environment Agency to improve habitat along the connecting stretch of river and add features to the weir to enable the endangered mammal to pass safely. Additionally, a new and improved mink raft has been installed on the nature reserve with a team of trained volunteer responders at the ready if triggered - the aim being to provide a safe haven once they get here through the eradication of American Mink, a non-native species, which has been a contributing factor to their decline through predation.

Large-scale restoration

In August and September 2023, Watford Borough Council led a major restoration project on the wetlands in Cassiobury Park LNR to desilt former watercress beds, transforming an area larger than a football pitch into an area of shallow pools with plenty of marginal vegetation. These, alongside additional ponds and scrapes, will soon become home to a diverse ecosystem for wading birds, amphibians, invertebrates and reptiles and will be ideal for Water Voles and Water Shrews should they (hopefully) move in. The main works are complete, but please be aware that the area is temporarily closed while the new habitats stabilise.

Coming together to make a difference

As you can see, volunteers play a vital role in protecting, maintaining and creating habitats where wildlife can thrive and people can enjoy a close connection with nature at Cassiobury Park Nature Reserve – the work here really is a tale of collaboration and community.  If you would like to volunteer to support this work, here are some of the ways you can get involved:

1. The Trust leads weekday work parties at Cassiobury Park. You can express your interest in joining one of these by completing the enquiry form here. Tick the Nature Reserve Work Party option and express your interest in Cassiobury Park in the ‘About You’ section.
2. The Trust works with Friends of Cassiobury Park, leading their conservation work parties, which take place on the third Saturday of the month. Find out more about how you can get involved with those here.
3. The Trust are working with Community Connections on projects to improve the health of Watford’s rivers. Find out more about what they are doing and how you might be able to support their projects here.

Find out more

You can also find out more about the collaboration and the work that began last summer to transform a large area of former watercress beds at Cassiobury Park Nature Reserve into a wildlife sanctuary in this news article ‘Works to start on exciting wetland restoration project in Cassiobury Park Nature Reserve’ which was published by Watford Borough Council.

Cassiobury Park Nature Reserve is well worth a visit whatever the season and its wetlands are key to that. Find out practical information about discovering this wonderful oasis for yourself here.