Life on the coast
The coastal zone is a fascinating place – it forms the interface between the sea and the land. These two environments are so different, however, that there is very little overlap and the high-water mark forms a distinct boundary between marine and terrestrial life.
Above this boundary sand dunes and machair, saltmarsh, shingle and cliffs provide habitats for a wealth of wildlife highly adapted to suit the conditions that, although essentially terrestrial, are still strongly influenced by the sea. Plants and animals have to cope with the specific stresses that living by the sea brings, such as drought, exposure, highly mobile mud and sand, salt spray and even occasional flooding by salty sea water. In this hostile environment, wildlife often require clever adaptations to survive. Only very few flowering plants, such as eel grass which grows along with seaweeds in the intertidal zone, are able to survive below the high-water mark.
Only a limited number of plants are even able to live near the high-water mark. Those, such as glasswort and sea blite, which make up the lower saltmarsh and do get regularly flooded by the tide, have succulent leaves which prevent the plant drying out when uncovered by water. Sea rocket forms an annual strandline vegetation and marram grass actually grows better if buried by sand and, therefore, thrives in sand dunes. Sea thrift is able to cling onto rocky shores and cliffs despite there being minimal soil cover. Moving further inland, away from the stressful impacts of the sea, particularly salt spray, other less tolerant plants become more common and the floral richness increases.
Of all the animals, birds are the most obvious and vocal inhabitants of the coastline. In spring and summer months, sea cliffs come alive with seabirds squabbling and bickering over nesting sites. In comparison, over the winter months sheltered estuaries teem with hundreds of thousands of waders and wildfowl attracted by the plentiful food and safe roosts of the mudflats and saltmarsh. Just as important are the mammals, amphibians and invertebrates which characterise the different coastal habitats and have adapted to life by the sea.