Summer 2000

Coastal changes at Birkdale

Article by Dr. Philip H Smith MBE

The coastline at Birkdale has changed dramatically in the last few years, leading to expressions of concern in the local press. So just what is going on?

For many decades, instead of growing outwards, the sand-dune front between Ainsdale and Birkdale hardly altered. Yet we know that the beach was getting much wider. In theory, there should have been plenty of sand blowing up from the foreshore to create new sandhills but this did not happen. The reason was that pioneer plants that trap the sand and begin the process of new dune formation were being destroyed by the action of cars, trampling feet and mechanized beach-cleaning. Recent changes in beach management restricted the area accessible to cars, used stud fences to prevent cars parking right up to the foot of the dunes and altered the way beach cleaning takes place. The result has been the rapid development of young sand-dunes over a distance of about 3km.

This natural process began in 1986 when plants started to grow on Birkdale beach. Normally, these would have been washed away during winter storms but the beach had become so wide that the energy of the waves was absorbed and the plants survived to trap sand during the summer. Gradually, sandy hummocks built up, the outer ones accumulating more and more sand to form a ridge of embryo dunes about 100m out from the existing dune front These are now up to 1 m high. The lower lying area behind the ridge has become waterlogged as rainfall can no longer drain away down the gently sloping beach. Thus, a seasonally flooded dune slack has formed - the largest on the entire dune coast.

These changes are important for two main reasons. Firstly, global climate change is resulting in a rise in sea-level and increasing storminess. This means our coastline and properties are increasingly at risk from flooding by the sea. The sand-dunes represent a natural, free and highly effective defence against the sea. So anything that leads to a widening of the protective dune belt needs to be encouraged.

Secondly, the Sefton Coast sand-dunes are internationally important for wildlife. A significant proportion of this is associated with the early stages of dune and slack formation. Over several decades, some of these special animals and plants have been struggling to survive as their habitats have become too mature. Now, between Ainsdale and Birkdale, they are thriving again. Since 1997, about 95 different kinds of flowering plants have been recorded in the new area, many of them distinctly scarce. Examples include the beautiful Lesser Centaury Centaurium pulchellum and the odd-looking Strawberry Clover Trifolium fragiferum, both of which are abundant in the big slack. Natterjack Toads have started to colonise the area, while birds have also responded with Ringed Plovers and Lapwings breeding successfully.

All of the area is within an existing Site of Special Scientific Interest and is part of the European candidate Special Area of Conservation, so we have an international responsibility to look after it. Indeed, it would be against both British and European law to do anything that damages it.

A final point; Birkdale beach is still there - it has just moved a little to the west in the same way that has been happening naturally for thousands of years.