Invasive non-native aquatic plants are a major global threat to wetland ecosystem services, including agriculture, flood control and biodiversity. They can infest water bodies such as ditches, ponds, and canals to form dense vegetative mats that out-compete native flora and reduce oxygen levels. Non-native aquatic species are expanding rapidly as a consequence of international travel and trade, climate change, and land use impacts. Despite increasing efforts and many millions of pounds spent trying to control invasive species in the UK, many non-native aquatic species are proving resilient to effective management. This research programme incorporates two of the most problematic species, Australian Swamp Stonecrop (Crassula helmsii) and Floating Pennywort (Hydrocotle ranunculoides), in order to develop effective management and monitoring methods.
This programme focuses upon the control of C. helmsii and H. ranunculoides on the Pevensey Levels wetland, East Sussex, UK. The Levels represent one of the largest wetland landscapes in south east England and are of global nature conservation significance. However, the area is infested with invasive aquatic plants to such an extent that the site could lose its conservation designations if they are not controlled. Projects are funded by the Environment Agency with additional support from Natural England.
This project commenced in October 2013 and will end in December 2019.
The programme includes two complementary projects with aims to:
This programme will improve the scientific basis of invasive aquatic plant management by focusing upon the control and monitoring of C. helmsii and H. ranunculoides on the Pevensey Levels wetland. The data collected and analysed will provide new evidence about changes to plant diversity, species assemblage and community dynamics as a result of invasion by non-native species. The research will provide evidence for the effectiveness of different control methods for these two invasive species. The effects of nutrients and climate change on the growth and expansion capability of H. ranunculoides will also be determined for the very first time. The application of a sUAS to facilitate assessment of control methods represents a novel contribution to invasive species management. This study will monitor the effects of a biological control agent developed by CABI (Centre for Agriculture and Biosciences International). The Pevensey Levels may be the first site worldwide in which a biological agent is released to control C. helmsii.
Anticipated outcomes from the project include a plan of eradication of invasive C. helmsii and H. ranunculoides from the Pevensey Levels wetland using the preferred option(s) of treatment and a control brief for contractors to be used nationally. Scientific publications relating to the monitoring and control of the two invasive species will also be produced.
Chris JoyceGary BilottaNiall BurnsideJane Birch (PhD student)Conor Strong (PhD student)
CABI (Centre for Agriculture and Biosciences International)