The Dungeness peninsula sits on an aquifer (a body of well-saturated rocks, gravel, sand, or silt that make way for the easy movement of water) and as such there are no controls on water levels on any of the lakes. This directly impacts the seabird colonies on the reserve as climate change induced weather patterns cause wetter winters and cooler springs. This meant the islands on the lakes here were under water during April and May - key months for nesting seabirds, and this tied in with recent large mortality events such as avian influenza which has led to a tough few years for seabirds.
Since 2017 we have been raising island heights on lakes with some good success stories, including this year, when the islands supported the first fledged Avocet chick in 20 years and common tern chicks too - a real success for the team.
Last year the RSPB was awarded funding for Natural England’s Species Recovery Programme which focused on island creation on two lakes, ‘New Excavations’ and ‘Denge Marsh’, both of which were suffering from higher water levels submerging shallower areas for much of the year, causing the loss of breeding sites. The plan was to utilise some of the lower, submerged shingle on top of other areas to create islands. This would cause the reduction of submerged habitat but would have the benefit of leaving areas out of the water in others. We calculated that we had enough material for at least two hectares of island space across the two lakes using this method.
Before work started the team spent some of last winter clearing vegetation from some of the island locations to assist with the delivery of the works programme. They also cleared a lot of the fringing willow from around the outside of the lake which was encroaching on habitat for the marshmallow plant. This is the foodplant of the rare Marshmallow Moth and it also causes shading of habitat which could be preferential for the medicinal leech. The reserve is nationally important for the medicinal leech and holds a significant proportion of the UK population.
All of the islands on New Excavations Lake are now complete and are already supporting large flocks of Lapwing, Great White Egrets and Gulls and providing great views for visitors in the hides.
Even though the work is not yet complete, we have already seen an increase in the variety of species visiting the reserve this year. These include Great Northern and Black Throated Divers, Black, Artic, Sandwich and Common Terns, Common, Greater and Lesser Black Back Gulls, Avocets, Plovers, Ruff, Curlew, Wood and Pectoral Sandpipers.
Given the success of the other island projects in recent years, we are confident that this project will continue to support the fragile seabird population, as well as safeguard the colonies of Medicinal Leech and Marshmallow Moth. We also look forward to welcoming all our visitors to hopefully witness some first-class wildlife for years to come.
