Increasing coastal change has impact on wildlife
Research shows how an increasingly dynamic coastline could radically change the face of wildlife on our coast in the coming decades. The next century will see rising sea levels, with the 8,050 miles (12,955 km) of UK coastline going through a process of accelerated and immense change. Increasingly, extreme weather events will potentially lead to huge turmoil for wildlife along this much-loved habitat where millions of us spend the summer months. A list of six species that might be seriously affected by our ever-changing coastline due to coastal erosion and climate change has been revealed by the National Trust:
- Little Tern: because of their nesting habits, the species' nests can be very vulnerable to exceptional high tides and summer storms, which are likely to become more frequent because of climate change. Winter storms and higher rates of beach erosion can also mean that places where they nested last year are no longer suitable when they migrate back to the UK each spring.
- Puffin: a combination of overfishing and warming seas has led to the bony and indigestible Snake Pipefish, scarcely found in our waters ten years ago, moving north to replace the Puffins' main food source, the sand eel. Puffin chicks have occasionally been found dead, having choked trying to swallow pipefish. Last summer's wash-out saw a number of Puffins' burrows flooded, while an exceptionally harsh winter and spring storms this year led to the worst bird wreck in 50 years, with hundreds of Puffins, Guillemots and Razorbills washing up dead along the north-east coast, presumed to have starved in the difficult conditions.
- Oysterplant: now nationally scarce and appearing on the current Red List in the near-threatened category, the oysterplant grows on exposed shingle beaches along the north-west coast of England and Scotland, as well as in Northern Ireland, where it is legally protected. Like other coastal plants such as the yellow-horned poppy, it requires some disturbance to maintain its open shingle habitat, but extreme storms could wash it away completely. Most population losses have been at the southern end of its range, caused by extreme storms, excessive recreational pressures, coastal squeeze and removal of shingle from beaches. However, as its seeds can be dispersed over long distances by the sea, there is the potential for it to spread and colonise new sites.
- Triggerfish: warming seas have led to an influx of invasive non-native species on our shores, such as zebra mussels and japweed, which can proliferate on boats, jetties, and in rock pools, able to survive in increasingly moderate sea temperatures. Perhaps most striking, however, are the occasional sightings of new natives such as the grey triggerfish, normally found in the warmer waters of the Atlantic and Mediterranean, off the coast of North Wales. The triggerfish's appearance off the Welsh coast gives a taste of how our marine ecosystems could see profound changes in coming years.
- Glanville Fritillary: a butterfly that exemplifies the boom-and-bust nature of coastal wildlife. Once found as far north as Lincolnshire, it has become restricted to the coastal landslips on the south-west coast of the Isle of Wight, pushed out by intensive farming which limits its caterpillars' main food source, ribwort plantain. Like many species which live on our coasts, it relies on highly specialised conditions — a gradually eroding, warm, south-facing cliff, with only the first stages of colonisation by plants. The greatest threats to its habitat therefore include the overstabilisation of cliffs through invasive plant species, and habitat loss through coastal squeeze. But increased erosion could also make cliffs too unstable for the vegetation it depends on — and with unpredictable weather caused by climate change we could lose it from our shores completely. Conversely, if climate change leads to warmer weather, the Glanville Fritillary could recolonise the mainland from the Isle of Wight.
- Cliff Tiger Beetle: though it is a hunter, this species on a very specific habitat. It relies on relatively large areas of bare clay being exposed through cliff slumps and slippages, living beside wet seepages along the bare cliff face. Two of its greatest threats are coastal development and the overstabilisation of soft cliffs (whether natural or human-induced). The increased mobility of cliffs this spring followed by hot weather this July has helped it, but it is vulnerable to catastrophic events in the few places that it does survive. Like many insects, the Cliff Tiger Beetle lacks the ability to move if conditions suddenly become unfavourable. It is only capable of short flights, so if it is lost from an area it may be difficult for it to recolonise.
David Bullock, the National Trust's head of nature conservation, said "The coast is at the forefront of how a changing climate will affect wildlife in the UK and is very vulnerable to the forces of change. Over the past decade we've been developing a better understanding of the coastline that we care for and in particular the 50% that will be affected by increased coastal erosion or flooding in the future. Our six coastal 'canaries in the mine' indicate how plants, animals and ourselves will have to live with an increasing rate of environmental change."
The UK coastline is already being affected by rising sea levels and projections suggest that, by 2100, sea levels will be more than half a metre higher than at present. Erosion is increasing, with the British Geological Survey reporting a four-to-five-fold increase in the number of landslides during July and December 2012 in comparison with previous years.
But warming seas and the increased unpredictability of weather could also have a radical impact on coastal habitats and wildlife. Matthew Oates, a national specialist on nature and wildlife, explained: "Climate change could change the face of our coastal flora and fauna. With rising sea levels, our rich mud flats could simply disappear. Wildlife that relies on the gradual erosion of soft rock cliffs or lives on loose sand and shingle habitats could be caught out by an increasingly mobile landscape as a result of extremes in weather."
"Extreme weather will be a big factor. We're seeing more and more superlatives — the hottest, coldest, wettest or driest months on record. Even on hard rock cliffs less affected by increased erosion, we are likely to see the boom and bust of more specialist plants and animals, as they suffer from increased flooding, salt deposition or drought stress. Unfortunately there may be more bust than boom."