Habitats

Saline Lagoon

The Fleet is the UK’s largest tidal saline lagoon, supporting a rich and distinctive community of marine and brackish‑water species, many of which are rare or specially adapted to lagoon environments.

Its varying salinity shapes the distribution of plants and animals along its length. The shallow lagoon also provides vital feeding and nursery grounds for fish, birds, and invertebrates.

Seagrass Beds

Seagrass, also known as eelgrass or Zostera, is a flowering plant that lives in seawater and forms dense underwater meadows. Although often unseen beneath the surface, this habitat is incredibly important, providing vital nursery areas for many rare and protected marine species.

The long, grass‑like leaves provide shelter and feeding grounds, while the extensive root and rhizome systems help stabilise the seabed and play a major role in carbon capture, locking away significant amounts of carbon in the sediment. The seagrass beds of the Fleet are internationally important, covering more than 240 hectares in the West Fleet, west of the Narrows.

Coastal Vegetated Shingle 

Vegetated shingle is extremely rare worldwide, and shingle stable enough to support vegetation is rarer still. Vegetation can establish only where the stones have settled sufficiently and fine sediments have accumulated to anchor root systems. Chesil Beach is one of the UK’s largest and most significant shingle systems, with important conservation value. It hosts a wide variety of rare, salt‑tolerant plants, which in turn support specialised wildlife.

The shingle vegetation at Chesil can be divided into three distinct zones:

Mobile bare shingle 

Found near sea level, this zone is regularly inundated by waves, causing continual movement of the shingle. As a result, very few plants can survive in these harsh, shifting conditions.

Sparsely vegetated shingle  

Located on the outer flank and the higher inner flanks of the shingle ridge, this area supports pioneer species such as sea kale, sea pea, and yellow horned poppy. These plants are adapted to drought, salt spray, occasional wave action, and have long root systems that help them withstand the unstable substrate.

Established coastal vegetation 

Found on the inner lower flanks of Chesil, where shingle has gradually stabilised through the accumulation of sediment and plant growth. Here, vegetation forms a more continuous cover, supporting increasingly complex plant communities, including sea campion, thrift, bird’s‑foot trefoil, and various grasses and lichens.

Intertidal Zone

Also known as mudflats or tidal flats, the intertidal zone is the coastal band that lies above water at low tide and underwater at high tide. It forms in sheltered areas where fine silts and clays settle out of calmer water, creating stable, nutrient‑rich sediments that support dense invertebrate communities, which in turn provide an abundant food source for a wide variety of wading birds and wildfowl.

Saltmarsh

This habitat forms on the upper shore of the intertidal zone, developing in sheltered areas where water movement is slow, and mud and silt accumulate, creating a stable substrate for halophytic (salt-loving) plants.

Vegetation within a saltmarsh is arranged in distinct zones according to how frequently each area is flooded. Glassworts (Salicornia spp.) dominate the lower marsh, where they are regularly and often heavily inundated, while species such as sea aster and sea purslane thrive higher up, where flooding is shorter in duration.

These ecosystems are highly productive and rich in invertebrates, which in turn feed larger predators such as wading birds. Beyond their ecological value, saltmarshes provide coastal protection, absorbing wave energy and reducing erosion. They also act as carbon sinks, trapping sediment and burying organic matter that can store carbon for many thousands of years.

Mediterranean-Thermo-atlantic Halophilous Scrub 

An exceptionally rare habitat found at the uppermost reaches of saltmarsh systems, composed of salt-tolerant shrubby vegetation. Characterised by their resilience to high salinity and periodic inundation, these communities are dominated by species such as shrubby seablite and sea purslane.

Reedbeds 

A predominantly water‑logged wetland habitat, stands of common reed provide essential feeding and breeding grounds for many small birds, mammals, and invertebrates. Reed also plays an important role in filtering pollutants and purifying the water. Its extensive rhizome systems help anchor the soil, stabilising the substrate and reducing erosion.

Withybeds 

Withybeds are areas containing willows, traditionally managed for the harvesting of willow rods for baskets, thatching and fencing. Willow is well adapted to wetland conditions, and its ability to grow quickly and regenerate after cutting makes it particularly well-suited to withybeds.

Despite being managed, these areas remain highly suitable for wildlife; coppicing and pollarding create a varied structure within the habitat. This structural diversity supports a wide range of species: dense young regrowth offers shelter for small mammals and nesting sites for birds, while older stems provide habitat for mosses, lichens, and a variety of invertebrates.

The damp soils and standing water commonly found in withybeds also attract amphibians and aquatic insects, thereby contributing to their overall ecological richness.

Fleet Hinterland 

Comprising scrub, woodland, grassland and farmland – a habitat familiar and widespread across the UK, yet in combination with Chesil and Fleet it holds significant ecological value. These terrestrial habitats sit immediately alongside one of Britain’s most dynamic coastal systems.

Their proximity provides essential shelter, feeding grounds, and movement corridors for wildlife that depend on both land and sea. This blend of habitats strengthens the wider ecosystem's resilience, offering refuge during extreme weather, buffering sensitive coastal zones, and contributing to the overall ecological richness that defines the Chesil and Fleet landscape.