Ponds, Pools and Lochans





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The term acidification is applied to the process by which naturally acid waterbodies become more acidic, usually as a result of human activity. Acidification is mainly caused by the deposition of acids from the atmosphere (acid rain) derived from the burning of fossil fuels (mainly by power stations and vehicles). Acidification can also be caused by runoff from conifer plantations.


Algal blooms

Proliferation of microscopic planktonic algae, often exacerbated by nutrient pollution, but sometimes occurring naturally.



Frogs, toads and newts.


Aquatic plants

A group combining both submerged and floating-leaved species (and excluding marginal plants).



A group of plants or animals recorded together. The term is used in preference to community because the latter implies an interaction between species.


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Base-poor soils

Soils which have little capacity to neutralise acids (especially from acidified rain) making waterbodies that drain from these soils more vulnerable to acidification.



The variability among living organisms including diversity within species, between species and of ecosystems.



The total mass of living matter within a given unit of area (e.g. per square metre).



The plant and animal life of a region or ecosystem, as in a pond or other body of water.



Best Management Practice, a shorthand term for urban drainage best management practice, a set of techniques used to control and manage urban runoff, particularly as part of SUDS schemes.



British Trust for Conservation Volunteers.


Buffer zone

A protective, neutral area between distinct environments (e.g. a grass strip, scrub or wet organic soil between farmland and a pond).


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The total area of land from which water drains into any given pond, loch, river, or other body of water.



A distinctive group of green algae (Characeae), known as stoneworts, which superficially resemble vascular plants in their size and the complexity of their structure. They are particularly associated with unpolluted waters rich in calcium.


Common Agricultural Policy (CAP)

The CAP is a central element in the European Unions institutional system and has been the forerunner of the single market (which ensures free movement of goods, services, capital and people, in the 15 Member States of the Union). The objectives of the CAP are (i) to increase productivity, (ii) to ensure a fair standard of living for the agricultural Community, (iii) to stabilise markets, (iv) to assure food supplies, and (v) to provide consumers with food at reasonable prices.


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Department of the Environment, Transport and the Regions.


DETR Lowland Pond Survey.

A survey of the ecological quality and numbers of ponds in lowland Britain (England, Wales and Scotland) undertaken in 1996 for the DETR by Pond Action and the Institute of Terrestrial Ecology.


Drawdown zone

Zone at the margin of ponds and lochs which is flooded in winter but which dries out in summer and autumn as water levels drop naturally during drier weather. In reservoirs large and unnaturally rapid drawdowns may occur causing extensive damage to marginal ecosystems.



General name for a group of six species of small free-floating plants which often form a complete cover on the water surface. Abundant growths of Common and Least Duckweed often occur on polluted or shaded ponds. The other species are generally indicative of higher quality water, or occur only in high quality habitats. The species that occur in Britain are: Common, Least, Ivy-leaved, Greater, Fat and Rootless Duckweeds. The respective scientific names for these plants are Lemna minor, L. minuta, L. trisulca, Spirodela polyrhiza, L. gibba and Wolffia arhiza.


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The study of the relationships between living organisms and their environment.



A community of interdependent organisms together with the environment they inhabit and with which they interact (e.g. a pond, an oakwood).


Emergent plants

Wetland plants which typically have most of their leaves above water level, e.g., tall emergent species such as bulrush (Typha latifolia) and soft rush (Juncus effusus); wetland herbs such as water forget-me-not (Myosotis scorpioides) and low-growing grasses such as creeping bent (Agrostis stolonifera).

Environmentally Sensitive Area (ESA)

ESAs are parts of the country of particularly high landscape, wildlife or historic value which are threatened by changes in farming practices. Incentives are offered to farmers to adopt agricultural practices which will safeguard and enhance the rural environment and create improvements in public access. There are now 22 ESAs in England and Scotland covering some 10% of agricultural land. They are administered by the Scottish Executive Rural Affairs Department or the Ministry of Agriculture, Fisheries and Food (England and Wales only).



High nutrient status e.g. typically Total Phosphorus concentration 0.03 - 0.10 mg l-1, Inorganic Nitrogen concentration 0.5 - 1.5 mg l-1, pH greater than 7.4.


Eutrophication is the term applied to the physical, chemical and biological changes which occur when nutrient concentrations in ponds, lakes and rivers are increased as a result of natural or anthropogenic processes. Eutrophication is mainly of concern where it results from pollution caused by the release of nutrients from point or diffuse sources (e.g. runoff from farmland and urban areas, sewage treatment works effluents). In all cases eutrophication leads to increased algal growth but effects on other biota depend on the initial starting condition of the waterbody; in oligotrophic and mesotrophic waterbodies, eutrophication leads to loss of species dependent on low nutrient status in favour of species associated with higher nutrient concentrations. In eutrophic waters, further enrichment (hypertrophy) can lead to complete elimination of submerged aquatic plants and consequent damage to animal assemblages through loss of habitat.

Eutrophic Standing Waters Habitat Action Plan

Part of the UK Biodiversity Action Plan process to identify actions for the Habitat Action Plan conservation of eutrophic standing waters.



The combined evaporation from the soil surface and the transpiration from plants.


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Filamentous algae

Aggregations of single-celled algae that grow in long strings or mats in water and are either attached or free floating. Dense growths of filamentous algae are often associated with nutrient enriched waters but also occur naturally in lower abundances. They provide habitat for a wide range of invertebrate animals.

Floating-leaved plants

Aquatic plants with most of their leaves floating on the water surface, e.g., Common Duckweed (Lemna minor), water lilies (Nuphar and Nymphaea).



The Farming and Wildlife Advisory Group (FWAG) is the foremost UK based organisation providing conservation advice to the farming community, and promotes environmentally responsible farming. FWAG provides advice on conservation in the widest sense, including wildlife, landscape and public access.


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The study of the physical nature and history of the earth.



Geographical Information System, computer-based systems for mapping and analysing data.



Water that occupies pores and crevices in soils and rocks, below the surface and above a layer of impermeable materials (as opposed to surface water which remains at or close to the land surface).


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The native environment or specific surroundings where a plant or animal naturally grows or lives. The surroundings include physical factors such as temperature, moisture, and light together with biological factors such as the presence of food or predator organisms.



A collective terms for reptiles (snakes, lizards) and amphibians (frogs, toads, newts).



The study of water and water movement above, upon and beneath the ground.



Very high nutrient status e.g. typically Total Phosphorous concentration greater than 0.10 mg l-1, Inorganic Nitrogen concentration greater than 1.5 mg l-1.

Hydrostatic pressure

The pressure in a fluid in equilibrium which is due solely to the weight of fluid above.


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Insect eating animals (may sometimes be applied to insectivorous plants such as sundews).


Institute of Terrestrial Ecology.


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Joint Nature Conservation Committee.


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Local Biodiversity Action Plan.


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Larger invertebrate animals, easily visible to the naked eye, such as snails, beetles, dragonflies.


Mesotrophic Lakes Habitat Action Plan

Part of the UK Biodiversity Action Plan process to identify actions for the conservation of mesotrophic standing waters.



Smaller invertebrate animals, difficult to see with the naked eye.



Larger wetland plants typically referring to vascular wetland plants, mosses, liverworts and charophyte species.



Ministry of Agriculture, Fisheries and Food.


Marginal plants

Wetland plants growing at or near to the margin of waterbodies in shallow water or seasonally flooded soils.



Freely developed bend in a river.



Moderate nutrient status e.g. typically Total Phosphorus concentration 0.01 - 0.03 mg l-1, Inorganic Nitrogen concentration 0.3 - 0.65 mg l-1, pH around 7.


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Nationally uncommon plant

A species designated as Nationally Scarce or recorded from 100 or fewer 10 km squares in Britain.


Nationally uncommon plant

A species designated as Nationally Scarce or recorded from 100 or fewer 10 km squares in Britain.



National Planning Policy Guidance.



National Nature Reserve.



National Pond Survey.


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Low nutrient stats e.g. typically Total Phosphorus concentration 0.005 - 0.010 mg l-1, Inorganic Nitrogen concentration 0.02 - 0.4 mg l-1, pH 6-7.


Operation Brightwater

Pond conservation project undertaken between 1990 and 1993 by Scottish Conservation Projects.


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Pond Conservation Group.



A measure of the acidity or alkalinity of a substance based on the number of hydrogen ions in a litre of solution. pH 7 represents neutrality, smaller values are acid, larger values are alkaline.



Animals (usually fish) that feed on plankton.


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Red Data Book (RDB)

Red Data Books of Britain and Ireland list species of plants or animals in danger of extinction in the British Isles (they many be widespread elsewhere in Europe). Species are categorised according to the degree of threat they face. For plants, RDB categories follow the new IUCN guidelines (IUCN, 1994). For invertebrates, the earlier nationally defined standards set by JNCC are followed.



Royal Society for the Prevention of Accidents.



Rare Species Score. Value representing sum of numerical scores given to uncommon species in order to reflect their rarity value i.e. 2= locally common species, 64 = RDB1.



Royal Society for the Protection of Birds.


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A member of the fish family Salmonidae which includes salmon, trout and sea trout.



Scottish Conservation Projects.


Second-tier sites

Sites which are important for nature conservation but not of high enough quality or importance to be designated as SSSIs.



Scottish Environment Protection Agency.



Scottish Natural Heritage.



A group of organisms which resemble each other and which will not normally breed with members of another group.


Species richness

The number of plant or animal species recorded in a particular habitat or sample.


Species Rarity Index (SRI)

A numerical assessment of the average species rarity of a particular assemblage or sample.



Site of Special Scientific Interest.


Submerged plants

Aquatic plants which are generally submerged for most of the year (except for flowers), e.g., hornworts (Ceratophyllum spp.), water milfoils (Myriophyllum spp.).



See Sustainable Urban Drainage Systems.


Surface water

Water which occurs on or near to the ground surface.


Sustainable Urban Drainage Systems (SUDS)

SUDS schemes are a group of techniques designed to control the damaging impacts of urban runoff. They combine pollution control measures with techniques for reducing the rate at which water runs off of paved surfaces into surrounding streams and rivers. SUDS schemes also aim to provide new wetland habitats and to improve the landscape and environment for people living in urban areas. SUDS schemes are made up of four main elements: (i) permeable pavements, (ii) filter strips and swales, (iii) infiltration devices and (iv) basins and wetlands.


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Trophic Ranking Score. The Trophic Ranking Score system is based on the presence of indicator plant species, weighted (on a 1 to 10 scale) according to the mean nutrient status of the waterbodies in which they typically occur (from dystrophic to highly eutrophic). The average Trophic Ranking Score from each site therefore gives an approximate assessment of the nutrient status of the waterbody.


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Wetland plants

All wetland plant species, including those which are emergent, floating-leaved, and submerged. A standard list of wetland plants is given in the Guide to the methods of the National Pond Survey (Pond Action, 1998).


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