River Tweed

General site character

• Tidal rivers, Estuaries, Mud flats, Sand flats, Lagoons (including saltwork basins) (1%)
  
• Inland water bodies (Standing water, Running water) (96%)
  
• Bogs, Marshes, Water fringed vegetation, Fens (2%)
  
• Broad-leaved deciduous woodland (1%)
  

Annex I habitats that are a primary reason for selection of this site

• 3260 Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation

  The Tweed represents sub-type 2 in the north-eastern part of its range. It is the most species-rich example, by far, of a river with Ranunculus in Scotland, and is the only site selected for this habitat in Scotland. The river has a high ecological diversity which reflects the mixed geology of the catchment. Stream water-crowfoot Ranunculus penicillatus ssp. pseudofluitans, a species of southern rivers and streams, here occurs at its most northerly location as does fan-leaved water-crowfoot R. circinatus, along with river water-crowfoot R. fluitans, common water-crowfoot R. aquatilis, pond water-crowfoot R. peltatus and a range of hybrids. The Tweed is also the most northerly site for flowering-rush Butomus umbellatus.

Annex I habitats present as a qualifying feature, but not a primary reason for selection of this site

• Not Applicable

Annex II species that are a primary reason for selection of this site

• 1106 Atlantic salmon Salmo salar

  The River Tweed supports a very large, high-quality salmon Salmo salar population in a river which drains a large catchment on the east coast of the UK, with sub-catchments in both Scotland and England. The Tweed is the best example in Britain of a large river showing a strong nutrient gradient along its length, with oligotrophic conditions in its headwaters, and nutrient-rich lowland conditions just before it enters the sea at Berwick. The high proportion of the River Tweed accessible to salmon, and the variety of habitat conditions in the river, has resulted in the Scottish section of the river supporting the full range of salmon life-history types, with sub-populations of spring, summer salmon and grilse all being present. The extensive system supports a significant proportion of the Scottish salmon resource. In recent years, the salmon catch in the River Tweed is the highest in Scotland, with up to 15% of all salmon caught. Considerable work has been done by the Scottish Environment Protection Agency (and previously the Tweed River Purification Board) and the River Tweed Foundation in tackling pollution and easing the passage of salmon past artificial barriers in the river. This has reversed many of the river’s historical problems with water quality and access for salmon.

• 1355 Otter Lutra lutra

  This large river system contains extensive water and riparian habitat suitable for otters Lutra lutra. The extensive tributary burns provide good feeding habitat. The area provides extensive suitable habitat for all the necessary aspects of otter’s life cycle and the site is a good representative of the south-east lowlands of Scotland and the north-east of England.

Annex II species present as a qualifying feature, but not a primary reason for site selection

• 1095 Sea lamprey Petromyzon marinus
• 1096 Brook lamprey Lampetra planeri
• 1099 River lamprey Lampetra fluviatilis