Errit Lough () is a

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

lake in the west of Ireland. It is located in west

County Roscommon County Roscommon () is a Counties of Ireland, county in Republic of Ireland, Ireland. It is part of the province of Connacht and the Northern and Western Region. It is the List of Irish counties by area, 11th largest Irish county by area and Li ...

in the catchment of the Boyle River. The lake is a

Natura 2000 Natura 2000 is a network of nature protection areas in the territory of the European Union. It is made up of Special Areas of Conservation and Special Protection Areas designated under the Habitats Directive and the Birds Directive, respectiv ...

site. It is protected as a

Special Area of Conservation A special area of conservation (SAC) is defined in the European Union's Habitats Directive (92/43/EEC), also known as the ''Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora''. They are to protect the 220 habitats and ap ...

(or SAC) since May 2016 under the qualification of a specific habitat type: the presence of ‘

Hard Water Hard water is water that has a high mineral content (in contrast with "soft water"). Hard water is formed when water percolates through deposits of limestone, chalk or gypsum, which are largely made up of calcium and magnesium carbonates, bic ...

Lakes’, alternatively known as ‘Hard oligo-mesotrophic waters with benthic vegetation of ''Chara spp''.’

Location

Errit Lough is located approximately 10 km south-west of the town of

Ballaghaderreen Ballaghaderreen () is a town in County Roscommon, Ireland. It was part of County Mayo prior to 1898. It is in the north-west of the county, near the borders with counties Mayo and Sligo, just off the N5 road. The population was 2,387 in the 2 ...

in County Roscommon. The lake is situated in the upper part of the Boyle River catchment. The area of Errit Lough included in the SAC designation is located in the townlands of Cloondart, Derreenamackaun, Errit, Gortaganny (Electoral District Artagh South) and Tully (Electoral District Artagh South) in County Roscommon. Schedule 1 of the Statutory Instrument for this site identifies it as encompassing an area of 84.59 ha.

SAC qualification

The Errit Lough site was proposed as a Site of Community Importance (SCI) in 1998. In 2016, the site was designated as a

, with site code IE0000607. Statutory Instrument 266 of 2016 established the site as an SAC. The feature which qualifies this site for SAC status is the presence of

Lakes – this habitat is also known as ‘‘Hard oligo-mesotrophic waters with benthic vegetation of ''Chara spp''.’. Under the EU

Habitats Directive The Habitats Directive (more formally known as Council Directive 92/43/EEC on the Conservation of natural habitats and of wild fauna and flora) is a directive adopted by the European Community in 1992 as a response to the Berne Convention. The ...

, this is an Annex I habitat type (code 3140). The Interpretation Manual of European Union Habitats defines this habitat as comprising:

“Lakes and pools with waters fairly rich in dissolved bases (pH often 6-7) (Pal. 22.12) or with mostly blue to greenish, very clear, waters poor (to moderate) in nutrients, base-rich (pH often >7.5) (Pal. 22.15). The bottom of these unpolluted water bodies are covered with charophyte, ''Chara'' and ''Nitella'', algal carpets. In the Boreal region this habitat type includes small calcareous-rich oligo-mesotrophic gyttja pools with dense ''Chara'' (dominating species is ''Chara strigosa'') carpets, often surrounded by various eutrophic fens and pine bogs.”

Hard water Hard water is water that has a high mineral content (in contrast with "soft water"). Hard water is formed when water percolates through deposits of limestone, chalk or gypsum, which are largely made up of calcium and magnesium carbonates, bic ...

lakes are typically base-rich, oligotrophic and unpolluted, with clear water. The NPWS publication "Benthic vegetation in Irish marl lakes: monitoring habitat 3140 condition 2011 to 2018" notes that the alkalinity of this lake was 136 mg/l CaCO³ and the euphotic depth (a measure of water clarity: the depth at which photosynthetic available radiation is 1% of its surface value) was 3.3 m. Typically lakes with total phosphorus of less than 0.01 mg/l have euphotic depth of over 5.0 m, but Lough Errit, a high-colour lake (of over 45 Hazen units), has low levels of phosphorus (total phosphorus of approximately 0.01 mg/l) and a low euphotic depth. This document notes four Charophyte species occurring in this lake, with

charophyte Charophyta () is a paraphyletic group of freshwater green algae, called charophytes (), sometimes treated as a division, yet also as a superdivision. The terrestrial plants, the Embryophyta emerged deep within Charophyta, possibly from terres ...

cover of 0.52 (52%). It is noted that in Ireland,

marl Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. M ...

lakes and cut-over bogs often occur in the same location, an issue for this habitat type is the leaching of coloured water into these lakes, resulting in a high water colour. This may explain the low levels of deeper water vegetation in Errit Lough.

Vegetation

The east side of this marl lake has exposed stony shores. On the west side of the lake are more sheltered areas. Within these more protected bays can be found emergent species such as Common Club-rush (''Scirpus lacustris'' or ''Schoenoplectus lacustris'') and

Common Reed ''Phragmites australis'', known as the common reed, is a species of flowering plant in the grass family Poaceae. It is a wetland grass that can grow up to tall and has a cosmopolitan distribution worldwide. Description ''Phragmites australis' ...

(Phragmites australis).

Bottle Sedge ''Carex rostrata'', the bottle sedge or beaked sedge, is a perennial species of sedge in the family Cyperaceae. Range and habitat The species is native to Holarctic fens and can be found in Canada and the northern part of the United States, and ...

(''Carex rostrata'') and Common Spike-rush (''Eleocharis palustris'') also occur on the west side of the site. As part of the designation criteria for the site (Hard Water lake with Chara Spp), there are beds of

stonewort Charales is an order of freshwater green algae in the division Charophyta, class Charophyceae, commonly known as stoneworts. Depending on the treatment of the genus '' Nitellopsis'', living (extant) species are placed into either one family ( ...

species (''Chara spp'') growing on the lake bed. These species include ''Chara pedunculata'', ''C. rudis'', ''C. desmacantha'' and ''C. fragilis''. In certain areas of the lake, floating Yellow water-lily (''Nuphar lutea'') are recorded.

Nearby Special Areas of Conservation and proposed Natural Heritage Areas

As can be seen from the National Parks and Wildlife Service (NPWS) designated sites map, other designated SAC sites nearby include Urlaur Lough (NPWS site code 001571), Derrinea bog (NPWS site code 000604), Carrowbehy/Caher Bog (NPWS site code 000597), Drumalough Bog (NPWS site code 002338), and the

River Moy The River Moy () is a river in the west of Ireland. Name Ptolemy's ''Geography'' (2nd century AD) described a river called Λιβνιου (''Libniu'', perhaps from *''lei''- "flow"), which probably referred to the River Moy. The Moy is first ...

SAC (NPWS site code 002298). This concentration of designated SACs in the area indicates that this location is ecologically very valuable. The Errit Lough site has been included as a proposed Natural Heritage Area (or pNHA) by the National Parks and Wildlife Service (NPWS). Other nearby pNHA sites include Urlaur Lough, Carrowbehy/Caher Bog, Derrinea Bog, Mannin And Island Lakes, Drumalough Bog and Lough Glinn.

Other features

Geology

The area surrounding the lake is a County Geological Site (or CGS). This area comprises the Erris and Cloonagh Loughs Deltas (site code RO012). The deltas are wide, flat-topped ridges of gravel and sand, situated above the nearby bog area. The deltas are considered to be good examples of deglacial, ice-marginal, meltwater-deposited features which frequently form at the edge of glacial lakes. The deltas were deposited at this site during deglaciation after the last Ice Age, at the edge of the northwestward-retreating ice sheet and date from the Quaternary period. These deltas were formed on

Lower Carboniferous Lower may refer to: * ''Lower'' (album), 2025 album by Benjamin Booker *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is sit ...

limestone bedrock and are made up of limestone clasts, which came from the bedrock around the site. The ice carried them until they were released into a meltwater conduit within the ice. They were then deposited at the margin of the ice sub-aqueously at the point where the river left the ice, flowing in a southeastward direction.

Archaeology

The Historic Environment Viewer map of Irish recorded monuments includes a number of historic features at Errit Lough. A number of

crannóg A crannog (; ; ) is typically a partially or entirely artificial island, usually constructed in lakes, bogs and estuarine waters of Ireland, Scotland, and Wales. Unlike the prehistoric pile dwellings around the Alps, which were built on shore ...

s have been recorded from the lake (site codes RO019-004, RO019-005, RO109-009 and RO019-011). From the recorded monuments records, site code RO019-010 refers to a well (with no evidence that it is a holy well) known as Tober Skeheen, which has a pump-house. Site RO019-006 refers to a circular embanked enclosure with external diameter of approximately 35 metres, which was noted on the 1837 Irish Ordnance Survey maps. It is suggested from these records that this may have been a rath. Site RO019-008 refers to a

souterrain ''Souterrain'' (from French ', meaning "subterrain", is a name given by archaeologists to a type of underground structure associated mainly with the European Atlantic Iron Age. These structures appear to have been brought northwards from Gaul d ...

sited on the crest of a low north-south ridge south-west of the lake. The precise location is unknown and the information about it comes from local knowledge. Site RO019-012 to the east of the lake refers to a children’s burial ground.

Walking trails

There is a walking trail around Errit Lough, which is part of the Lough Errit Walking Trail, which includes a range of looped walks of between 4 and 11 km in length. Dogs on leads are allowed but the walks are not buggy-accessible.

Conservation objectives

The primary conservation objective for the site is to “maintain the favourable conservation condition of Hard oligo-mesotrophic waters with benthic vegetation of ''Chara spp''. in Errit Lough SAC”. This includes objectives to maintain the habitat area /extent subject to natural processes, to prevent decline of the habitat distribution, to prevent decline of the lake vegetation composition, zonation and depth, and to maintain the hydrological regime (groundwater flows) in order to support the habitat. The water quality should be maintained with low (oligotrophic) nutrient concentrations, high transparency, high chlorophyll, phytoplankton and algal biomass status.

References

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Environmental Protection Agency (Ireland) The Environmental Protection Agency (EPA) is responsible for protecting and improving the environment as a valuable asset for the people of Ireland. It operates independently under the Department of the Environment, Climate and Communications. Hi ...

, access-date = 11 October 2022 {{cite web , url = https://www.logainm.ie/en/110059 , title = Loch Eirid/Errit Lough , work = Placenames Database of Ireland (logainm.ie) , publisher = Government of Ireland - Department of Arts, Heritage and the Gaeltacht and

Dublin City University Dublin City University (abbreviated as DCU) () is a Third-level education in the Republic of Ireland, university based on the Northside, Dublin, Northside of Dublin, Republic of Ireland, Ireland. Created as the ''National Institute for Highe ...

, accessdate = 30 January 2020 Errit Special Areas of Conservation in the Republic of Ireland Natura 2000 in Ireland Protected areas of County Roscommon