Temporal vegetation changes in relation to dune sealing on Natural England land at Formby Point, Sefton Coast. Aneurin O’Neil1,2 Irene Delgado-Fernandez1 & Paul Ashton2 1Geography Department - Edge Hill University 2Biology Department – Edge Hill University

Introduction/context Coastal dunes are a dynamic boundary between the land and sea (Cooper & McKenna, 2008), also providing a natural buffer to sea level rise (Davidson-Arnott, 2005). Heavily influenced by anthropogenic activity, often conflict between conservationists, coastal scientists and tourists (Ritchie, 2001). Climate influences dune geomorphology. Wind speed - quantity and rate of sediment transfer (Hesp, 2002). Wave magnitude and frequency – Quantity of sediment available (Aagard, et al. 2004). Climate change and increased growing season has led to dune sealing; a reduction in bare sand area across north-west Europe (Jackson & Cooper, 2011; Provoost, et al. 2011).

Current research (Pye, et al. 2014; Delgado-Fernandez, et al Current research (Pye, et al. 2014; Delgado-Fernandez, et al. submitted; Provoost, et al. 2011; Arens, et al. 2012) focuses solely on the decline in the area of bare sand. Research on changes in vegetation composition is lacking. This project investigates the change in vegetation composition on Natural England land at Formby Point, looking at management strategies and climatic variables.

Study site The Sefton coast is located in North-West England, covering 32km of coastline between the Ribble estuary and south of Crosby. Contains a 17km long and 1.5km wide stretch of sand dunes. National and international conservation designations (Smith, 1999). Southport Formby Ainsdale Hightown Crosby/ Liverpool

180 ha of bare sand lost between 1945 and 2010 (Delgado-Fernandez, et al. submitted). Through a combination of natural and anthropogenic factors. Physical: Sediment availability influenced by speed and frequency of high energy wave events and vegetation extent/form (Pye, 1990). Anthropogenic:High levels of planted non-native scrub/tree species have become naturalised to the dunes, leading to a reduction in sand mobility. Corsican pine (Pinus nigra) and Sea buckthorn (Hippophae rhamnoides) leads to dune fossilisation.

Aims Investigate the changes in vegetation composition and extent between 1945 and 2010. Investigate potential relationships between environmental/anthropogenic factors and vegetation change.

Methods Four aerial photographs of the Sefton coastline selected; 1945, 1961, 1989 and 2010 for near bi-decadal coverage. Supervised classifications used to classify pine woodland, deciduous woodland/scrub, grassland and bare sand. Deemed to be the most appropriate method for vegetation classification, deemed to be most appropriate method. Building on methods of Pye, et al (2014) and Delgado-Fernandez, et al. (submitted). Perhaps follow up point three with something like “thought to be the most appropriate method of classifying vegetation”

Climate data, comprising of mean, maximum and minimum temperatures, rainfall quantities, sunlight hours, wind speeds and gust speeds from 1940 to 2010 (or shorter when data was not present) was analysed over 70 year, decadal and seasonal scales. Seasonal scales to observe changes in growing conditions over short time periods. Explain how seasonal scales were calculated. 5 year averages preceding each epoch.

Vegetation changes

Loss of pine in north-west, confined to the east of study site, scrub increased in north of area throughout the centre, more grass to the west of the image, bare sand lost in shoreward part of dunes.

70 year and decadal trends

Seasonal graphs

Discussion Shift to scrub between 1945 and 1989 potentially influenced by myxomatosis outbreak in the 1950’s (Smith, 2005). Introduction of firebreaks and clearance of Pinus nigra subsp. laricio woodland between 1961 and 1989. Scrub encroachment followed (Sturgess, 1993). Bare sand lost predominantly in the north, potentially with cessation of sand winning in late 1950’s.

Destabilisation management followed in 1990’s (Wheeler, 1993). Two sections of plantation woodland removed. Scrub removal highly active (Smith, 1999). Management of scrub occurs due to grazing by sheep, cattle and rabbits (Millett & Edmondson, 2013). Higher nutrient levels may increase vegetation cover in mobile dunes (Jones, et al. 2004). Bare sand increased on the shoreline but decreased in the dune field, loss of habitat.

Conclusions First study to investigate the vegetation element of dune sealing. Increases in winter mean, maximum and minimum temperatures and sunlight hours, combined with higher summer and winter rainfall totals and slower wind/gust speeds suggest better growing conditions leading to the spread of vegetation and decline of bare sand. Jackson & Cooper (2011) and Pye, et al. (2014). Grassland and scrub/deciduous woodland main causes.

Further research 1. How do the trends observed on Natural England land relate to the rest of the Sefton coast? 2. The climatic data requires substantial levels of statistical analysis. Mann-Kendal test and Sen-slope test. 3. What changes have occurred in soil nutrient levels across Natural England land?

Acknowledgements Sefton Coast Partnership for providing aerial photography. Natural England for site access permissions. Dr Phil Smith for assisting with site visits and providing local historical information.