Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. The National Trust is asking beach-goers to post pictures on Instagram to help monitor coastal erosion.A photo stand has been erected at Studland Bay in Dorset, inviting passersby to stick their smartphones into a slot and snap photos.The sign then asks them to post the images on social media using the hashtag #NTshiftingshores.There is just one rule: no zooming or filters.They will then be swept up from social media by the charity and made into a timelapse film showing how the shoreline has changed over time.The National Trust, which manages more than 780 miles of coastlines across Britain, aims to use the data to help plan ahead to protect wildlife, flora, fauna and buildings.Hundreds of people have already posted pictures online, showering praise on the charity for its innovative idea and calling for it to be rolled out across all beaches.One Twitter user captioned their coastal photo: “For anyone who thought the Instagram generation needed to take a break from #social on their days out, why not embrace it and use it to your advantage?! #ntshiftingshores”.Another wrote: “Doing my bit for the National Trust project at Studland Bay #ntshiftingshores”.More than 400 people have published their photos on Instagram, with tourists from America and Thailand among those joining in. Pictures date back as far as June 2016.The National Trust says: “By understanding what is happening to the natural environment around our coast we can make well-informed choices about whether and where to continue maintaining hard sea defences, or to adapt and work with nature rather than against it.”Working with other land owners, communities, beach users and with local government we can create more joined up and better managed stretches of coastline.”The coming years will be critical to the future wellbeing of our coast and we will play our part.”The UK has one of the longest national coastline in Europe, stretching for more than 8,000 miles.Studland Bay is four miles long and has views of Old Harry Rocks and the Isle of Wight.Erosion is when rocks along the coastline are worn away. This can happen when powerful waves smash against them, or pebbles carried by the sea grind down rocks like sandpaper. High winds, rain and flooding can also contribute.This can cause degradation of land and damage to infrastructure, as well as disrupt wildlife habitats.Storms and high tides battered UK coastlines in 2013 and 2014, causing “considerable damage” and levels of erosion that experts would normally see every five to 15 years, according to the National Trust.