The foreshore is “what the sea left behind”, what was tossed up by the incoming and outgoing tides, the movements of the waves. The foreshore, whether longer or shorter, thicker or thinner, forms a band that includes an accumulation of living elements or those that come from living elements (algae, dead wood), and debris that comes from human activities, like plastic bags, pieces of fishing nets, oil balls etc.
When the foreshore is not too polluted, it constitutes a true ecosystem that can contribute to the life of the coastline, sheltering many natural organisms – and particularly crustaceans that live in the sand – under dead algae and other natural detritus.
As it breaks down, beached algae and other organic debris can also provide the plants higher up the foreshore with nutrients that allow them to develop in tandem with associated species. This whole group can also contribute to retaining sand and other sediments, and also allow beaches to be maintained and developed.
After this a whole food chain is set up, from the smallest organisms and insects, to the birds that feed on them, passing on to crabs and other crustaceans.
So, preserving the foreshore, not suppressing it on beaches for touristic reasons, is [a way] to preserve the natural environment and all that coastline life, which is often invisible but nonetheless indispensible.