Purple Dewplant Management Techniques: The Effectiveness of Removal and Impacts on Native Flora Regrowth, in the Coastal Sand Dunes of Jersey, Channel Islands

Coastal sand dune systems are one of the most rare and natural remaining ecosystem types on
Europe. The dynamism created by variable climate and influx of sand creates a diverse mosaic of
habitat which favour a small diversity of specialised species. The British Isles are particularly rich in
dune systems, however variable nature of these systems is becoming threatened by stabilisation.
Stabilisation leads to a closed dune system which is vulnerable to the impacts of invasive species. The
dunes will lose its open habitat and specialised species, ultimately succussing into more shrubby
grasslands and woodlands. Les Blanches Banques SSI, located on the west coast of Jersey, Channel
Islands is amongst the ten largest sand dune systems of the British Isles, and fourth richest in floral
diversity. It is one of the few remaining dune systems with a mosaic of open dune habitats and hosts
a variety of flora and fauna not found elsewhere in the British Isles.
The coastal strip of Les Blanches Banques is heavily invaded by the succulent plant Disphyma
crassifolium, or purple dewplant. Adapted to harsher environments, the plant outcompetes native
flora, thick mats covering stretches of the strip. Hand pulling purple dewplant has been the common
technique for removal however is labour intensive and slow. The foamstream technique applies 850C
plant oils to the ground, as a 100% natural ‘weedkiller’. This report investigates the effectiveness of
these management techniques, in their removal of purple dewplant, and the impacts on native flora
regrowth. The results will help advise the Invasive Species Team, Environment, Government of Jersey
on how best to manage the impacts purple dewplant.