This paper describes the importance of groundwater to the coastal habitats of the sand dunes in North West England. The sand dunes support an aquifer that extends for 20km between Liverpool and Southport. They provide a range of natural habitats, sites of special scientific interest and a number of nature reserves (https://www.sefton.gov.uk/around-sefton/coast-countryside.aspx). It also supports cultural services (landscape, tourism, art) and international quality recreation facilities such as the famous Royal Birkdale Golf Club and others. Groundwater levels in the sand dunes have been monitored monthly since 1972 and at 30 minute intervals since 2010. Seasonal changes in recharge cause groundwater levels to rise and fall 0.5-1.0m between winter and summer. The long term observations suggest a gradual lowering of water levels of 0.15m over the last 45 years, despite the sea level boundary rising by 0.1m over the same period (https://www.ntslf.org/products/sea-level-trends).
The importance of groundwater in the various nature reserves is demonstrated by the emergence of fresh water ponds each winter. These areas are extremely biodiverse, supporting up to 100 plant species per square meter (Houston, 2008, Natural England, 2014) together with IUCN Red List species (www.iucnredlist.org/) such as the Natterjack Toad (Epidalea calamita).
Concerns have been raised that climatic change and human actions such as agricultural drainage in the adjacent areas may adversely affect the groundwater levels which in turn may cause breeding ponds to dry up and the loss of biodiversity (Curreli et. al., 2013). Another impact is a reduction in the natural sub irrigation of the fairways and greens of the numerous golf courses in the area.
Various 1D and 2D groundwater models have been developed to explain the annual and long term changes in ground water levels (Clarke and Sanitwong, 2009, Abesser et. al., 2017). These have been tested against the 45+ years of monitoring data. Information from this modelling work is enabling conservation planners to identify areas of the dune system that will be of concern to managers. Coastal processes are creating new land that will become suitable for the creation of new nature reserves. A new approach to conservation may become necessary, where ecosystems relocate spatially and conservation management will have to become more dynamic.
Abesser, C., Clarke, D., Hughes, A. G., & Robins, N. S. (2017). DOI: 10.1007/s11852-017-0525-5
Clarke, D. and Sanitwong Na Ayuttaya (2009). DOI:10.1007/s11852-009-0066-7
Curreli, A., Wallace, H., Freeman, C., Hollingham, M., Stratford, C., Johnson, H. and Jones, L. (2013). DOI: 10.1016/j.scitotenv.2012.11.035
Houston, J. A. (2008). Management of Natura 2000 habitats. 2190 Humid dune slacks. European Commission.
Natural England (2014). Survey and analysis of vegetation and hydrological change in English dune slack habitats. Annex 2 - Site report for Sefton Coast: Ainsdale NNR, Ainsdale LNR, Birkdale Hills LNR. publications.naturalengland.org.uk/file/6635636215775232