Over the last few months we have been working with South West Water to help protect eight of their sites that are within Sites of Special Scientific Interest (SSSIs). SSSIs are protected areas designated under the Wildlife and Countryside Act 1981 for the rare and nationally important habitats, geological features and species that inhabit them. Ecologist Teri discusses SSSIs and what she has been doing to help protect them:

Countess Wear Waste Water Treatment Works (WWTW) in Exeter is one such site that can be found within a SSSI. Designated for its national importance of wintering wildfowl and waders, the Exe Estuary contains many intertidal habitats including saltmarshes, flood plain fens and mudflats all covering a designated area of 2190.11 hectares.

While the treatment works only covers a small area, it holds important wetland habitats, such as reed beds, wet woodlands and standing water bodies. These habitats support the wider SSSI’s rare invertebrate assemblages and species such as the rare Reed Bed Ground Beetle (Demetrias imperialis), the nationally rare hoverfly (Pipiza lugubris) and dragonfly species such as Hairy Dragonfly (Brachytron pratense) and Scarce Chaser (Libellula fulva). Many bird species also like to use the operational area throughout the year from mallards and teals to rooks, sparrow hawks and small passerine species.

However, there is one species on site that is currently causing a real threat to these habitats and is therefore one of the main management priorities at Countess Wear. This is the control of the invasive non-native species (INNS) Himalayan balsam (Impatiens glandulifera). Himalayan balsam outcompetes native flora which can have detrimental impacts on already rare and declining species.

Over the last four years Himalayan balsam has slowly increased in population at Countess Wear, partly due to little management during Covid-19 lockdowns in 2020 and 2021 which allowed the flowering heads to turn to seed causing its spread, followed by the difficulties in accessing newly populated areas of the site the following year. Although small pockets could be reached to control the species, the inability to access other areas meant that this invasive non-native species was able to continue to flourish.

Therefore in 2023 after further consultations and site visits, permissions were granted from Natural England to allow for some scrub clearance works and boardwalks to be installed allowing for access to areas which were previously inaccessible.  We hope that now that these additional features have been installed, we can start to control and eradicate this species from within the operational area, reducing the impacts it is having on site as well as reducing the potential for it to spread elsewhere within the catchment and SSSI. 

To stop the spread of invasive non-native species, always follow biosecurity protocols of Check, Clean and Dry. 

Find out more about Himalayan balsam here. 

Teri Nicholls, Ecologist

September 2024