Tayside Biodiversity Partnership Local Action Plan

Tayside Biodiversity - Tayside Biodiversity Action Plan - Water - Standing Open Water

DEFINITION

The standing open water habitat includes not only the open water but also to some extent the associated habitat around the water’s edge. This definition obviously provides considerable scope for overlap with other Habitat Action
Plans such as Wet Woodland, Wet Grassland and Freshwater Reedbeds. These habitats are considered more fully in their own Habitat Action Plans and it is important to recognise the transitions between them and refer, where necessary, to the appropriate HAPs.

Standing open waters include natural systems such as lochs, lochans and pools, as well as man-made waters such as reservoirs, ponds and gravel pits. The open water zone lies beyond the limits of swamp vegetation, but may contain submerged, free-floating or floating-leaved plants.

The range of standing open water types within this broad category means that only a general overview of some of the issues is possible within this Action Plan, but a separate Plan has been developed for the key habitat of Mesotrophic Lochs and future Plans will be developed for habitats such as Eutrophic Lochs, and Ponds, Pools and Lochans.

KEY SITES
The vast range and diversity of standing open water in Tayside means that there are many candidates for key sites.
Mesotrophic lochs are a UK priority habitat and these are discussed in detail in the Mesotrophic Lochs Action Plan.
Some sites which represent excellent examples of their kind or have particularly notable features are detailed below.

Loch Laidon

Loch Tay

Loch Brandy

Loch Con

Dunalastair Reservoir

Dun’s Dish

Loch Leven

Carsebreck Lochs

A dystrophic peaty loch.

A large oligotrophic loch and the largest loch in Tayside without any form of impoundment.

A high altitude oligotrophic loch with notable moss and liverwort populations and rare insects.

A high altitude oligotrophic loch supporting a diverse bird fauna, including rarities and with islands which demonstrate the sort of vegetation which may be expected at this altitude in the absence of grazing pressure.

A completely artificial shallow loch of considerable conservation value, including its plants and bird populations and some notable rarities.

A eutrophic loch with extensive surrounding swamp vegetation and notable ornithological interest.

Internationally important wintering and breeding wildfowl, diverse aquatic and riparian vegetation, invertebrate populations and an internationally famous trout fishery.

Second only to Loch Leven in Tayside for their wintering wildfowl populations.

CURRENT STATUS AND EXTENT OF HABITAT
Scotland has a large number of standing waterbodies with an estimated 150,700 ponds, pools ands lochans up to 2 hectares and 4,500 lochs greater than 2ha. Standing waters in Tayside cover a total of 134.66km2 and reflect much of the diversity found nationally. They range from large oligotrophic lochs such as Loch Tay (27.3km2) and Loch Rannoch (18.96km2) to smaller waterbodies such as Butterstone Loch (0.44km2) and pools of a few metres across.

Water quality of Lochs in Scotland and Tayside
There are 150 lochs in Scotland with a surface area above 1 km2 and 3,788 lochs over 0.04 km2. Scottish Natural Heritage (SNH) has identified around 27,000 lochs large enough to feature on the Ordnance Survey 1:50,000 scale maps with a surface area greater than approximately 0.0001 km2.

In 1995 SEPA’s loch water quality classification scheme was applied to all 150 lochs over 1 km2, together with 23 smaller lochs of particular local interest. The majority of lochs (143) were not significantly affected by human activity and were classified as ‘excellent/good’, but 27 were found to be significantly altered by human activity and classified as ‘fair’, whilst three were either ‘poor’ or ‘seriously polluted’. Of those lochs classified as ‘fair’, twenty (53 km2) were affected by eutrophication and ten (57 km2) by acidification.

In Tayside, 20 lochs were classified: 15 (97.41km2) were ‘excellent/good’, and 5 (30.87km2) ‘fair’. This was due to the effects of eutrophication on Loch Earn, Loch Leven, Loch of Lintrathen and Loch of the Lowes, and through acidification at Loch Laidon.

NATURE CONSERVATION IMPORTANCE
Standing waterbodies provide important and very rich habitats, particularly for aquatic invertebrates, wetland plants and amphibians. They are also used by a variety of mammals and birds. The importance of waterbodies and surrounding habitat in supporting rare species is underlined by several freshwater UK Biodiversity Action Plan (UK BAP) species. In Scotland these include: Great crested newt Triturus cristatus, Pillwort Pillularia globulifera and Slender naiad Najas flexilis. For other BAP species such as Water vole Arvicola terrestris, Otter Lutra lutra, Common scoter Melanitta nigra, Arctic charr Salvelinus alpinus and Brown trout Salmo trutta standing waterbodies may be a substantial component of the species’ habitat. Within the broad range of standing water types naturally mesotrophic and eutrophic lochs are considered of key national importance for biodiversity.

Water vole

This species has suffered one the most catastrophic declines of any British mammal with a predicted loss of 98% of its entire population in recent years. In the past it was found from Lowland Perthshire and Angus to high altitude catchment areas such as Ben Lawers and Glen Lyon. Recent surveys on some of these sites have concluded that they are locally extinct throughout most of their former range.

Water voles will use most types of freshwater systems: lochs, ponds, slow-moving rivers, raised bogs, marshes and wetlands, lowland drainage ditches and headstreams up to 600m. They eat a variety of waterside vegetation such as rushes, sedges and grasses and in late autumn save food in underground chambers to eat during the winter months when frost and snow cover the ground for long periods.

KEY SPECIES

P = UK Priority species C = UK species of conservation concern

Mammals	Water vole	Arvicola terrestris	P
	Otter	Lutra lutra	P
	Daubenton’s bat	Myotis daubentoni	C
Birds	Common scoter	Melanitta nigra	P
	Osprey	Pandion haliaetus	C
	Black-necked grebe	Podiceps nigricollis	C
	Whooper swan	Cygnus cygnus	C
	Wigeon	Anas penelope	C
	Gadwall	Anas strepera	C
	Pink-footed goose	Anser brachyrhynchos	C
	Greylag goose	Anser anser	C
	Pochard	Aythya ferina	C
	Goosander	Mergus merganser	C
	Red-breasted merganser	Mergus serrator	C
	Black-throated diver	Gavia arctica	C
	Shoveler	Anas clypeata	C
Amphibians	Great crested newt	Triturus cristatus	P
Fish	Atlantic salmon	Salmo salar	C
	Brown trout	Salmo trutta
	Arctic charr	Salvelinus alpinus	C
Invertebrates	Northern damselfly	Coenagrion hastulatum	C
Invertebrates	a diving beetle	Hydroporus rufifrons	P
Plants	Slender naiad	Najas flexilis	P
	Slender stonewort	Nitella gracilis	P
	Pillwort	Pillularia globulifera	P
	Hooker’s liverwort	Haplomitrium hookeri	C

Standing open waters have an important visual and aesthetic value and can also have considerable amenity value. The amenity use of open waterbodies includes activities such as fishing, shooting, boating and other watersports.