This section of coast is diverse not only due to the remoteness and inaccessibility of the cliffs and associated shore but also due to the mixed habitat. Bude alone offers freshwater, salt marsh, estuary, beach sand, pebbles, sand dunes, rocky outcrops, pools, cliff face, man-made features, shallow sloping shore, deep water and rocky crevices. The physical aspects of facing a powerful high energy body of water, the mobility and scouring action of the sand combined with fragility of cliffs does limit the diversity of organisms. However, there is plenty here if you know where to look.
What makes a good habitat?
As if the action of tides and waves wasn’t enough to contend with, the shore is made of different materials. Sand is mobile, it is difficult to make a home in, rock wears away at different rates, it offers greater stability but can be hard to hold onto. Some shores are muddy where an estuary carries silt from the land, this is poor in oxygen, gravel has large spaces in between the stones so oxygen is not a problem, but the stones rub against each other and dislodge of crush anything attached.
All of these habitats offer places to live, feed and breed to some form of life, the adaptations required are impressive. If you want a shore with huge biomass (lots of living matter) then a muddy one is best, despite being oxygen-poor, mud is normally extremely rich in nutrients and so supports lots of life but at a cost. The biodiversity is low (limited range of species) as not many creatures can adapt to the difficult conditions. A rocky shore may be rich in species but it is hard to find food and so the mass is reduced. Clearly, the best location has it all, a range of habitats each of a size that supports many creatures. Bude, has just this sort of mix but there is a factor here that reduces the potential diversity, the Atlantic.
This is a very hostile body of water, it stretches from here to the coast of America in an unbroken line. The potential for huge waves is there, add to this the gyre principal (movement of water caused by the changes in temperature between the equator and the poles, the shape of the land and underwater features etc) and Coriolis effect (where water moves around the globe in specific directions due to the rotation on our axis) and you have a complex, violent ocean. This force of water easily displaces organisms, it picks up sand, gravel and boulders and throws them around. It destroys cliffs and headlands, it tears up seabeds. The north coast is not for the weak and feeble, this factor reduces our diversity in comparison with the soft south.
Luckily most of our coast is sand or mudstone, this wears quickly but at different speeds and so huge numbers of cracks and crevices, caves and tunnels exist in the rock and these offer shelter from even the worst storms. Next time you watch a tiny blob of jelly uncurl into a delicate 1 cm long sea slug, think about these forces, it defies reason sometimes just how anything lives here.