Habitats and Species of the Humber Estuary

Habitats and Species of the Humber Estuary

Intertidal Mudflats and Sandflats

Intertidal mudflats and sandflats in the Humber Estuary are submerged at high tide and exposed at low tide, revealing nearly 50% of the Humber's bed. These flats are created by rich sediments that wash in and out of the estuary with every tide. They form a complex and highly productive ecosystem supporting a range of habitats and species, including invertebrates like marine worms and mollusks, which provide vital food for fish and birds.

Large-scale reclamation occurred in the Doncaster-Google area in the 17th century and at Sunk Island from the mid-18th to the early 20th century. More recent land reclamation requires compensation for unavoidable losses due to flood defense or port development. The estuary shows erosion in its outer and middle sections, while accretion occurs in the inner estuary.

Saltmarsh

Saltmarshes develop when salt-tolerant vegetation colonizes intertidal sediments in areas where tidal inundation is less frequent. Pioneer saltmarsh forms on the lower shore, leading to the development of Atlantic salt meadows in more stable conditions. The Humber Estuary supports approximately 627 hectares of saltmarsh on both banks, although upper marsh communities have been lost due to "coastal squeeze."

Saltmarshes are predominantly unglazed and provide habitats for nationally rare wildlife. Managed realignment mitigates losses from coastal squeeze by setting back sea defences to create intertidal land for saltmarsh development. Samphire, a pioneer saltmarsh plant, is essential for waterfowl and is also collected locally for food.

Coastal Lagoons

Coastal lagoons are shallow saltwater areas separated from the sea by sandbanks, shingle, or rock. They are a rare and threatened habitat supporting unique wildlife like the starlet sea anemone and tentacled lagoon worm. The Humber's lagoons host three nationally scarce invertebrate species, with Humberston Fatties near Calthorpe's being the third most important saline lagoon in Britain.

Sand Dunes

Coastal sand dunes develop behind sandy beaches as dry sand is blown landwards and trapped by obstacles and vegetation, forming a dune system. The Humber's sand dunes, covering over 200 hectares, are dynamic systems supporting species like sea holly. Though above the highest astronomical tide and outside the European Marine Site boundary, processes within the site affect them.

Grey Seals

Donna Nook supports one of England's largest grey seal breeding colonies, with hundreds of new pups born annually. Grey seals are rare, with the UK population representing about 40% of the world population and 95% of the EU population. Donna Nook is Britain's most south-easterly breeding colony, with 1,358 pups recorded in 2008.

Birds

The Humber is one of Europe's top ten estuaries for birds, supporting internationally important populations of seven species listed in Annex I of the Birds Directive: Marsh Harrier, Avocet, Little Tern, Bittern, Hen Harrier, Golden Plover, and Bar-tailed Godwit. These species face extinction, rarity, or vulnerability and require special conservation measures. The estuary supports around 150,000 waterfowl during winter and migrations, and important breeding populations of species like bittern, marsh harrier, and avocet in summer.

Sea and River Lamprey

Lampreys are primitive vertebrates with a distinct sucker-like mouth.

Sea Lamprey

Sea lamprey, the largest and least common of the three UK species, migrate to fresh water to spawn on clean gravel in rivers like the Swale, Urea, Nidd, and Wharfe. Larvae burrow in silt beds before migrating to the Humber Estuary and the sea.

River Lamprey

River lamprey, confined to Western Europe, spawn in UK rivers and need clean gravel and silt for their larvae. Larvae spend years in silt beds before migrating to estuaries and then upstream to spawn. They use the Humber as a migratory passage, with evidence indicating year-round presence.

This summary outlines the diverse and vital ecosystems within the Humber Estuary, highlighting the importance of conservation efforts to maintain and protect these habitats and species.