Aquatic macrophyte growth at Hickling Broad

Hickling Broad is one of the largest bodies of water within the Norfolk & Suffolk Broads, comprising 128ha of open water. The Broad contains species and habitats of high conservation importance, including rare and protected plant species in the stonewort family. The Broad also has a long history of water-based recreation.

The clearer water and healthy plant and stonewort growth that Hickling Broad has experienced over the last few years is an environmental success story and the rare wildlife of the nature reserve has benefitted from these improving aquatic conditions.

NWT’s priority is to take care of the nature reserve’s rare and special wildlife. We recognise that engaging the community and visitors with the wildlife and habitats of Hickling Broad is an important part of this work. This includes a commitment to providing access to the water space for recreational activities where it does not negatively impact the ecological condition of the site. The ecology and recreational activities must exist in harmony.

NWT recognises the concerns being expressed by some users of the Hickling water space that the volume of plants is impacting some types of recreational boating.

Removal of plant growth in the marked navigation channel

NWT is supportive of the removal of plant growth in the marked navigation channel and provides bank locations for depositing cut plant material.

Removal of plant growth outside the marked navigation channel

The rare stonewort species that grow outside of the navigation channel within Hickling Broad are legally protected by the Special Area of Conservation designation which is part of the Habitat Regulations. Carrying out any operations that might impact these species must therefore be consented by Natural England to be lawful. NWT supports this consent process as it is in place to ensure the rare stoneworts and the ecology they support thrive.

NWT worked with Natural England and the Broads Authority to carry out carefully monitored stonewort cutting trials to explore the impact of increased cutting on the overall stonewort population in the Broad**. The research identified that any additional cutting outside of the main channel would have a negative impact on stonewort species resident in Hickling Broad. Key findings included:

• Cutting had an effect on the height and cover of stoneworts for up to two seasons after the treatment.
• Within the stonewort bed, cutting inadvertently affected a greater area than just the cut treatment plots, with negative impacts on plant height and cover observed in the non-cut and control plots.
• Cutting stoneworts allowed other vascular plants to populate the cut areas, depressing the abundance and range of stonewort species present.

Furthermore, the latest 2024 Broads Authority plant surveys show that the stonewort are intermingled with the wider aquatic flora of the Broad so it would not be possible to undertake selective cuts of certain species without also cutting the stoneworts.

Due to the available conservation evidence, Natural England would not consent the cutting of plants outside of the navigation channel and at the current time NWT’s position is also that stonewort in this area of the Broad should not be cut. NWT would review this position as and when new evidence on the impact of cutting stonewort in Hickling Broad becomes available.

*The term ‘Aquatic macrophytes’ includes all aquatic plants growing in or near water that are large enough to be seen with the naked eye.

**(EXPERIMENTAL CHAROPHYTE (STONEWORT) CUTTING IN HICKLING BROAD 2017-2019 final Report. The Broads Authority 2020).