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Caithness Draft Index

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Caithness Draft Plan
The Caithness Biodiversity Group  -  October 2002

2. River, Loch & Wetland


Water is a key feature of the Caithness landscape, with distinctive wildlife as well as social and economic uses. Rivers and lochs are important for recreation and sport. The water quality and quantity is uniquely dependent on the management of habitats within their catchments.

Biodiversity Objectives

Objective 2.1 Maintain favourable water quality status in all water bodies.

Objective 2.2 Retain and enhance all existing areas of wetland and keep lochs and rivers in as natural a state as possible, with no barriers to fish migration.

Objective 2.3 Encourage responsible recreation (including angling, shooting, water sports) wherever possible.

Objective 2.4 Raise awareness of the importance of wetland and open water habitats, and encourage local pride in the value of the pristine freshwater environment.

Objective 2.5 Promote a holistic approach to freshwater conservation by encouraging co-operation between land and water users, and the use of practical guidance notes and professional advice from government agencies.

2.1 Rivers & lochs

Habitats & species

All of Caithness freshwater systems are highly regarded by local people for their recreational, scenic and environmental value. These pristine waters sustain important populations of Atlantic salmon, sea trout, brown trout, sticklebacks, eels, European otters, water voles, freshwater pearl mussels and various types of birds. Pipistrelle bats can be seen at dusk feeding over bodies of open water.

Caithness is bisected by its two principal rivers, the Wick and the Thurso. Their flood plains form a fertile band of land running south-east and north-west through the county respectively. The Rivers Forss, Thurso, Berriedale and Langwell all start as peatland burns and mineral rich springs deep in the heart of Caithness. In places, these rivers have cut gullies, whose steep sides harbour rich vegetation. Pyramidal bugle and prostrate juniper are important species here. Along the river banks the estuarine sedge and holy grass are nationally rare.

Caithness lochs range from nutrient-poor peat lochans (oligotrophic) throughout the ‘Flow Country’, to nutrient-rich lochs (eutrophic) such as St Johns Loch. In between are a number of lochs with intermediate nutrient levels (mesotrophic) such as Lochs Watten and Scarmclate. The biodiversity of the lochs is highly dependent on their water chemistry, which in turn is influenced by the nature of the surrounding rocks and soils. A good number of lochs contain a calcium-rich pale mud known as marl, and these lochs are particularly rich in character.

Most Caithness lochs sustain healthy populations of fish, notably brown trout, sticklebacks and eels, while Loch Calder also has ferrox trout and Arctic charr. Some like Loch More may contain salmon at certain times of the year. Virtually all lochs have an immense diversity of insect life including an abundance of mayfly, damsel flies, caddis fly and olives. Molluscs and crustaceans such as pea mussels, snails and freshwater shrimps are abundant in the fertile lochs of Caithness. These invertebrates form an important part of the diet of trout and the local bird life. Trout in turn are eaten by otters and rarer birds like divers and osprey. Aquatic plants range from bogbean to stonewort, and many lochs contain weed beds, which provide important shelter for fish and insects.

Habitat: (N: National priority, L: Local priority) Present in Caithness:
Rivers & burns (L) Yes
Lochs (L) Yes
Mesotrophic lochs (N) Yes
Eutrophic standing waters (N) Yes

Key species dependant on rivers & lochs:
Brown trout Freshwater shrimp Great northern diver Stonewort species
Sea trout Freshwater pearl mussel Grey heron Pyramidal bugle
Atlantic salmon Slavonian grebe Wader species Prostrate juniper
Stickleback Wigeon European otter Estuarine sedge
Arctic charr Greylag goose Water vole Holy grass
Ferrox trout Osprey Pipistrelle bat  
Mayfly Red-throated diver    
Damsel fly Black-throated diver    

Main issues

Agricultural and forestry run-off and leakage from septic tanks is a potential source of detrimental nutrient enrichment. In recent years, forestry techniques have improved and existing plantations are being restructured to reduce their effect on freshwaters.

Incorrect use of chemicals (herbicides, pesticides and sheep dip can all have a serious effect on rivers and lochs. Farmers and crofters must continue to be vigilant and adhere to legislation and existing codes of good practice regarding the use of such chemicals.

River and lochside developments, bank engineering, gravel extraction, water supply schemes and hydropower projects alter erosion or sedimentation patterns. Care must be taken not to modify the structure and patterns of water flow to the detriment of freshwater habitats and species. Road works and winter maintenance in particular can interfere with the movement of animals, especially fish.

In some areas, emergent and bank side vegetation has been lost due to land drainage, flood defence, bank protection works, cultivation or heavy grazing. Heavily trampled river banks are susceptible to erosion during floods. Limiting grazing on banks and planting deep rooted trees such as willow and alder will help to stabilise the riversides, whilst installing water troughs discourages animals from trampling at the waters edge. Agri-environmental grants may be available to help pay for some of this work.

Invasive, non-native species of fish, mammals, invertebrates and plants have caused problems for water courses elsewhere in Scotland, and we should avoid releasing such species in Caithness. Minnows are already an introduced non-native species in many of the county's lochs.

Acid rain is a threat that remains unquantified.

Current biodiversity projects

River Thurso walkway restoration project

Caithness & Sutherland Trout Angling Group improvements to water courses and bank habitats

Opportunities for action

· Demonstrate the importance of freshwater habitats with practical projects e.g. restoration of
  spawning burns for wild trout and salmon.

· Produce information on freshwater habitats of Caithness to show diversity of local wildlife
  dependent on this specific environment.

· Raise awareness of the importance of conserving the pristine nature of Caithness rivers and lochs,
  e.g. what can happen when a burn becomes polluted - loss of spawning habitats, invertebrates,

· Encourage agricultural interests to use buffer strips near freshwater systems to prevent bank

· Produce leaflet information on good practice for all water users on how to take care of their local

· Raise awareness through educational practice.

2.2 Wetlands

Habitats & species

Pockets of open water, reedbed and fen such as at Loch Lieurary, near Westfield or Loch of Durran near Castletown can be found within hollows of the rolling farm and croft land. The mosaic of arable land, fen and damp grassland is important for lowland breeding waders such as lapwing, curlew, snipe, redshank and oystercatcher.

A diverse and colourful range of aquatic plants is found in these open water and wetland habitats. The wetlands are carpeted with an array of flowers including marsh marigold, ragged robin, northern marsh orchid and water avens. There are three nationally scarce pondweeds and one scarce water lily. Four lochs have around their margins the nationally rare narrow small reed and one loch has the only known population in the world of the Scottish small reed.

Habitat: (N: National priority, L: Local priority) Present in Caithness:
Fens (N) Yes
Reedbeds (N) Yes

Key species dependant on wetlands:
Moorhen Lapwing Grey heron Water avens
Spotted crake Curlew Newt Pondweed species
Water rail Snipe Lizard Water lily
Reed bunting Redshank Marsh marigold Narrow small reed
Pintail duck Greenshank Ragged robin Scottish small reed
Shoveler duck Oyster catcher Northern marsh orchid  

Main issues

Securing the correct grazing balance is vital for the continued management of wetland habitats. Without management, overgrazing can occur, leading to a loss in the diversity of species. In today’s economic climate, there is also a real threat of undergrazing as land is abandoned, leading to dominance of rushes and other invasive species.

In the past, many small pockets of wetland were lost to agricultural improvements such as drainage and fertilising. Due to the present state of agriculture, this is less of a threat today.

Current biodiversity projects

Wetlands are being managed within agri-environmental schemes

Breeding bird surveys have taken place in recent years on protected sites

Opportunities for action

· Caithness-wide survey of breeding waders, linking breeding success to available habitat.

· Increase uptake of agri-environment schemes to maximise wetland habitat management.

Next : Farm and Croft Lands