This article is written by Cheshire Wildlife Trust and its local group Wirral Wildlife, using the guidance issued to Wirral Borough Council by Natural England, and with further advice on geomorphology, sediment accretion and estuarine habitats from coastal experts who know Wirral. Coastal change is natural; we are fortunate that here it is providing new habitat to help tackle the climate, environmental and well-being emergencies we face.
During the last ice age, Wirral was under a thick layer of ice. This gouged out the Dee Estuary and pressed down our part of the earth's crust. Since the ice melted about 10,000 years ago, the Dee Estuary has been slowly filling up with nutrient-rich sand and mud, known as sediment. The sediment comes mostly from the sea, by longshore drift along the North Wales coast. It is this accumulated sediment that makes the Wirral shores internationally important for nature conservation. It is full of worms, snails, crabs and other invertebrates. On these feed the thousands of birds which winter here, which would not be able to survive without this rich food.
The seabeds of the Dee and Mersey estuaries also store lots of carbon that has been absorbed over thousands of years, sealed underwater. If disturbed, this carbon is released, making our climate warmer and our seas more acidic. Readers will know about the effects of the climate emergency and current efforts to tackle it through the COP26 conference: we are part of nature, not separate from it. Salt marsh is one of the best habitats at taking carbon dioxide out of the atmosphere, on a par with peatlands and woodlands. (See Natural England report cited at end).
Sea levels have fluctuated widely since the last ice age and are currently rising as a result of increasing sea temperatures. Our piece of crust has been slowly coming up again since the weight of ice was removed, so the net sea level rise at Liverpool is currently about 5mm a year - which does not sound much until it is added up over a century and more. Our coasts are dynamic places, always changing. For the last century many of our coasts have been "frozen" in place by coastal defences. Can and should this be continued?
To help answer this, the national government has put in place a Shoreline Management Plan (SMP), about which there were local public meetings in 2012. Rev. Paul Rooney, Head of Geography and Environmental Science at Liverpool Hope University tells us that there has been a "tectonic change" in knowledge of coastal processes in the last 20 years - but we still cannot accurately predict the future from the past.
So what about Hoylake? The SMP decision for North Wirral, made by national experts, is to "hold the line" i.e. maintain the existing hard defences for at least 50 years from when the plan was made. After that defences may be removed at Leasowe Bay and natural sand dunes encouraged to take over. The SMP principle is to work with nature - but Liverpool Bay is not entirely natural, being affected by the canalisation of the Dee and Mersey and the dredging of the Liverpool Port approaches for shipping. At Hoylake, the energy of the water and sediment supply are key. The Hoyle Lake is now full of sediment. Hilbre and the East Hoyle Bank break some of the energy of the waves, tides and currents. So sand and some mud is being deposited on Hoylake shore, raising its level to the point where it provides excellent conditions for specialist plants. The colonisation by coastal plants is the result. Sand dunes are wonderful habitats for a suite of fascinating plants which we need to respect and which provide us with service by holding the sand together, so less blows inland. An on-going study of Hoylake shore by an expert professional botanist (Joshua Styles) has so far (by spring 2021) recorded 110 plant species, including twelve rare and unusual ones of at least regional significance. Spartina (Cord-grass) occupies much less than 5% of the vegetated area. All the species are native to the UK. Most of the species are now those characteristic of sand dune rather than salt marsh. This excellent collection has arrived naturally, because the shore provides the correct environment for their needs. This special and natural environment we now have on our shore is why every time the vegetation has been sprayed or scraped off, it returns. Natural England opinion (see guidance) is that at Hoylake the balance would be more towards sand dune than salt marsh, but detailed studies are needed to test this. These have now been commissioned by Wirral Borough Council.
In 2000, a report by Dr Alan Jemmett (then Dee Estuary Conservation Officer, now head of Merseyside Environmental Advisory Service) looked at the Hoylake foreshore and did a report to Wirral BC, which judged the continued removal of vegetation to be "unsustainable" on ecological and financial grounds. With money needed for other matters, surely we should embrace the natural opportunity that has developed on our coast.
At Parkgate, well up the Dee where there is less movement of waves, mostly mud was deposited, leading to permanent salt marsh. In contrast, Red Rocks Nature Reserve, round the corner from Hoylake shore, has been allowed to develop fairly naturally for the last twenty years. Here a new salt marsh, reed-marsh and sand-dune line have formed and are still increasing. In these new habitats natterjack toads sing, rare moths breed and much other wildlife is flourishing. Rats, mosquitoes and cord-grass are not problems at Red Rocks. West Kirby beach by the Sailing Centre is kept clear of plants by mechanical methods.
The best comparison to Hoylake, because it likewise faces Liverpool Bay, is in Sefton, all the way from Birkdale to Marshside, where coastal sediment has formed wildlife-rich new habitats. At Southport an amenity beach is kept as sand. We encourage you to walk along this shore and enjoy the wildlife.
North Wirral foreshore is internationally important for wintering birds, with many thousands there every year. How would development of salt marsh and sand dune affect them? Developing saltmarsh and sand dune would slightly reduce the feeding ground for the wading birds. The RSPB does not think the loss is significant, given the large amount of inter-tidal habitat available. The new salt marsh and sand dune could provide more roosting places at high tide. This would be valuable space for the birds, which have few places to go because of urban development round the Dee. We can help the resting birds by keeping ourselves, our dogs and our horses from disturbing the birds at high tide in autumn and winter.
The previous agreement between Natural England and Wirral Borough Council on the beach management has finished. In 2019 Wirral Borough Council declared an Environmental and Climate Emergency, as have many other local and national bodies. In the last few years, new evidence on the effects of the weed-killer formerly used on the beach (glyphosate) has emerged. It has been shown to reduce invertebrate populations, including those in the beach sediments. These invertebrates are the food supply for the wintering birds. The guidance of the Government’s ecological advisor, Natural England, is now in favour of letting nature take its course (see their guidance to Wirral Borough Council). They do allow the possibility of creating a limited amenity beach, as at West Kirby, using mechanical means.
Money is tight - is our money best used making the climate and environmental emergencies worse? Or could it be used to manage the natural sediments, keeping open sand where an amenity beach is needed and access for RNLI? Wirral Borough Council has at long last agreed to have a proper scientific investigation done, as Dr Jemmett recommended two decades back, to model what would develop naturally on this beach.
Look ahead 50-100 years. Sea level will continue to rise. Dunes and saltmarsh would protect the sea wall. What would our grandchildren want us to do?
For all these reasons, we should allow nature to take its course on Hoylake shore. We are very lucky to have more coastal wildlife able to thrive in our peninsula. New coastal habitat is a rarity in the UK and we should celebrate it.
Our mission, as Cheshire Wildlife Trust, is to bring wildlife back. We want to see more and better-connected wild spaces and the pressures on the environment reduced, and we work to improve the resilience of nature and restore broken ecosystems. We also believe that people’s wellbeing and the economy relies on a healthy, natural environment. Coastal processes are changing the beach at Hoylake and increasing the diversity of wildlife found there. There needs to be more understanding of the coastal change, habitat development and the value that this brings, and we are in favour of further studies to help achieve this. Hoylake beach is designated for nature conservation as a Site of Special Scientific Interest. As such, any management of the beach requires the written agreement of Natural England.
Wirral Wildlife committee
Cheshire Wildlife Trust
Shoreline Management Plan - www.mycoastline.org.uk
Wirral Coastal Strategy - www.wirral.gov.uk
Alan Jemmett's report:
Natural England Research Report NERR094 'Carbon Storage and Sequestration By Habitat: A Review of the Evidence' (second edition):