Area: 2,345.71 hectares.

Soil and geology

Neutral, shingle, sand, mud, alluvium, sedimentary, sandstone, gravel.

 Geomorphology and landscape

Lowland, coastal, floodplain, shingle bar, subtidal sediments (including sandbank/mudbank), intertidal sediments (including sandflat/mudflat), estuary.

Tidal flats 32.5%

Estuarine waters 32.5%

Freshwater marshes / pools: permanent 10%

Sand / shingle shores (including dune systems) 10%

Canals and drainage channels 5%

Salt marshes 5%

Marine beds (e.g., sea grass beds) 5%

General description of the physical features

The Exe catchment encompasses an area of 1,530km2. It drains diverse habitats ranging from the moorland of Exmoor National Park at the headwaters of the River Exe, to the Exe Estuary at Exmouth. The River Exe rises on Exmoor at 450m above sea level and descends 82.7 km. The main tributaries of the River Exe are the Rivers Culm, Barle, Clyst and the Creedy.

The catchment extends across several different landscape types. The rivers Exe and Barle rise in the wet open moorland of Exmoor, before running south-eastward through steep-sided valleys with extensive broad-leaved woodlands. Further east, smaller tributaries run off the Brendon Hills, with the River Haddeo dammed to create Wimbleball Reservoir. Man has modified much of Exmoor, with extensive enclosure and agricultural improvement in the nineteenth century.

The Estuary runs south-eastward for about 4 km from Exeter to the junction of the Ex and Clyst Rivers. Here it broadens, being over 2 km wide in places, and runs for a further 7 km to Exmouth, where it is sheltered from the sea by the unusual double spit across the mouth of the estuary and sand dunes of Dawlish Warren.

The site encompasses a partially enclosed tidal area comprising the waters, foreshore, low-lying land and three marshes and an unusual double spit across the mouth of the estuary, with the sand dunes of Dawlish Warren. Dawlish Warren and Pole Sands (a sand bank) form natural breakwaters between the approach channel and open water of Lyme Bay to the south west. These provide some protection against flooding and dangerous storm surges.

This complex of habitats supports internationally important numbers of wintering and passage waterfowl, as well as populations of breeding birds and nationally important rare plants and invertebrates.

The Warren supports a variety of plant and animal communities representative of south-west Britain, including the only remaining British mainland population of the sand crocus Romulea columnae. The site contains a full sequence of intertidal habitats which are important for invertebrate fauna. Tidal flats, saltmarsh, reedbeds, sand dunes and enclosed grazing marsh are all well represented. Exminster Marshes support regionally rare plants such as parsley water dropwort Oenanthe lachenalii and flowering rush Butomus umbellatus, and two species of nationally scarce dragonfly, the ruddy darter Sympetrum sanguinium and the hairy dragonfly Brachyton pratense.

The extensive areas of sand and mud are of marine nature conservation importance, largely due to the presence of Ophelia bicornis, a polychaete worm known from only one other site in Britain, and also for eelgrass Zostera spp. and Enteromorpha beds, and contain an abundance of invertebrates including extensive mussel Mytilus edulis beds.

The Orcombe rocks are a key geological feature displaying excellent coastal section in the sandstones, siltstones and mudstones (Benton, Cook and Turner 2002).

 Noteworthy flora

Sand crocus Romulea columnae

Parsley water dropwort Oenanthe lachenalii

Flowering rush Butomus umbellatus

Eelgrass Zostera spp.

 Birds

The estuary habitats are extremely productive and provide feeding areas for numerous birds, in particular waterfowl, that come here for protection and to feed. The reason that the area is protected is because the numbers of birds are of international and national importance with 20,263 waterfowl regularly overwintering here. Internationally important numbers of Dark-bellied brent goose, Branta bernicla 1,509 individuals, representing an average of B. bernicla, 1.5% of the GB population (5 year peak mean 1998/9-2002/3) and the black-tailed godwit, Limosa limosa islandica, 857 individuals, representing an average of 2.4% of the Iceland/W Europe population (5 year peak mean 1998/9-2002/3).

Of national importance:

 

Species regularly supported during the breeding season are the little tern, Sterna albifrons albifrons, W Europe 73 pairs, representing an average of 3.7% of the GB population (Mean 1992 to 1996)

 

Species with peak counts in spring/autumn:

Little egret, Egretta garzetta, West Mediterranean 81 individuals, representing an average of 4.9% of the GB population (5 year peak mean 1998/9- 2002/3)

Whimbrel, Numenius phaeopus, Europe/Western Africa 79 individuals, representing an average of 2.6% of the GB population (5 year peak mean 1998/9- 2002/3 - spring peak)

Common greenshank , Tringa nebularia, Europe/W Africa 54 individuals, representing an average of 9% of the GB population (5 year peak mean 1998/9- 2002/3)

Species with peak counts in winter:

Red-breasted merganser, Mergus serrator, NW and C Europe 114 individuals, representing an average of 1.1% of the GB population (5 year peak mean 1998/9- 2002/3)

Water rail, Rallus aquaticus, Europe 5 individuals, representing an average of 1.1% of the GB population (5 year peak mean 1998/9- 2002/3).

Special Protection Area general site character

Area 2,366.84 Ha. 79.4% marine.

Brent goose Branta bernicia with an overwintering population of c. 1,905.

Dunlin Calidris alpina with an overwintering population of c. 5,740.

Oystercatcher Haematopus ostralegus with an overwintering population of c. 4,265.

Black-tailed godwit Limosa limosa islandica with a population of c. 533.

Grey plover Pluvialis squatarola with a population of c. 471.

Slavonian grebe Podiceps auritus with a population of c. 20.

Avocet Recurviroostra avosetta with a population of c.

Waterfowl assemblage c. 23,811.

© Crown copyright. All rights reserved. Natural England [2015].