This habitat type is particularly important as a nesting and resting ground for birds and as a rookery for seals.
The vegetation cover is usually very sparse on the small islands; occasionally, some superficial deposit rocks are exposed. Dry-loving plants and lichens form patches of primary vegetation, many islands have no trees at all.
The vegetation of the small islands and islets is affected by the brackish water and the continuous rising of the earth, but wind, prolonged sunlight, and general dryness are also important, as are the nitrogen-rich bird faeces on some islands: in moderation, it promotes plant growth, but in very large quantities, on the contrary, it destroys the entire vegetation.
Estonia has more than three hundred islands with an area of one to ten hectares and more than a thousand even smaller islets and small islands (the total area of the latter is 3.35 km2).