In the UK, lowland raised bogs can be found in cool, humid areas such as the North-west lowlands of England, the Central and North-east lowlands of Scotland, Wales and Northern Ireland, but they are also found in Southern and Eastern areas, including Somerset and South Yorkshire. The size of the dome can vary, but may grow to over 12 metres in height, with the accumulation of peat separating it from the influence of groundwater, so that it becomes irrigated solely through precipitation. This is known as an "ombrotrophic" (rain-fed) bog, the surface of which is waterlogged, acidic and deficient in plant nutrients. The bog surface itself may support smaller pools, hummocks and lawns, created in part by the growth of plants. This patterned effect provides a range of micro-habitats which support different species assemblages.
Although usually low in plant diversity, this type of habitat supports specialised plant assemblages including members of the Sphagnum genus (e.g. Baltic bog moss Sphagnum balticum and Skye bog moss Sphagnum skyense). Vascular plants are also adapted to water logged conditions e.g. cotton grasses (Eriophorum spp.). Sphagnum mosses are the UK's primary peat forming species and are responsible for the "spongy" surface seen on these bogs. Their ability to store water is thought to be important in keeping the bog surface wet during the summer.
Lowland raised bogs support a number of breeding waders and wildfowl and invertebrates. Peat accumulation preserves a unique record of plant and animal remains as well as atmospheric deposits which can indicate historic patterns of land use and climate change.
There are three conditions which must be maintained for lowland raised bogs to persist:
- Water level: Increased water loss may lead to the system de-stablising as lowland raised bogs are a naturally waterlogged habitat.
- Solute level: Water inputs tend to be from precipitation alone and are therefore very low in solutes. An increase in the nutrient concentration to the system will alter the habitat in favour of non-bog species.
- Vegetation: The vegetation layer acts as a natural regulator for water loss and so the alteration of this may also de-stablise the habitat.
Since the beginning of the 19th Century, the area of lowland raised bog is thought to have dropped by around 94%, from 95,000ha to 6,000ha. These declines are a result of many factors including:
- Peat extraction
- Afforestion - As well as draining nearby areas, plantations act as an invasive seed source, possibly leading to the encroachment of scrub land and trees onto lowland raised bog
- Landfill development - The use of peat extraction areas for landfill
- Drainage - Lowland raised bogs which occur next to land drained for agriculture may be subject to drying
- Livestock and game management - Trampling and contamination with feed and droppings has a detrimental effect on lowland raised bogs
- Built development - Land reclamation and other developments affect the stability of lowland raised bogs.
Future threats are thought to include climate change (which will change rainfall patterns and groundwater table levels), and drainage activities which will also affect the groundwater level and therefore lead to desiccation.
Around 120 sites in the UK are designated as Sites of Special Scientific Interest (SSSIs) or Areas of Special Scientific Interest (ASSIs). Many important bogs are managed by statutory agencies through agreements with site owners. Around 17 lowland raised bogs are designated as National Nature Reserves (NNRs) but there are still important bog areas where commercial peat extraction occurs. Management and/or rehabilitation schemes are implemented for all NNRs and SSSIs/ASSIs where management agreements have been achieved with landowners. Annex 1 of the EC Habitats Directive includes 2 lowland raised bog habitats and the UK Government has proposed 24 active and 2 degraded raised bogs as Special Areas of Conservation (SACs) under the terms of the directive. Various areas are also designated as Special Protection Areas (SPAs) under the EC Birds Directive, or as Ramsar Sites under the Ramsar Convention. Other important sites receive additional protection and management through Wildlife Trust Reserves and RSPB nature reserves.
Several pieces of research and management have helped build up a large amount of information on lowland raised bogs.
- In 1996, Scottish Natural Heritage (SNH) published a report named "An inventory of lowland raised bogs in Great Britain". This inventory (which is ongoing), provides an assessment of the condition and conservation of this habitat and also records the status of the SSSI and NNR sites. It also identified two main condition classes, primary and secondary. Primary raised bogs are an unbroken profile of peat that has not been disturbed by actions such as peat cutting but may have some damage as a consequence of fire, drainage or scrub encroachment. Secondary bogs have been subject to partial peat removal.
- The Scottish Wildlife Trust (with EU Life funding for 3 years) gathered survey data for many of Scotland's lowland raised bogs and held an international Peatland Convention in 1995. This project also published "Conserving Bogs: The Management Handbook".
- Visitor facilities e.g. boardwalks, education packs and leaflets, have been designed to educate the public about the importance of such sites.
The lowland raised bog HAP sets out targets to improve the status of sites. These targets include maintaining the current distribution of lowland raised bog, maintaining or enhancing the condition of sites, establishing appropriate hydrological and management regimes and identifying areas, timescales and targets for restoration or improvement of significantly altered raised bogs. These targets will be met through a number of actions with lead agencies which include:
- Review and modify livestock support mechanisms in the Less Favourable Areas (LFAs) through further lobbying for reform of CAP to promote sustainable agricultural management of lowland raised bog.
- Initiate the development of Water Level Management Plans in Scotland, building on experiences gained in England and Wales
- Ensure the importance of lowland raised bogs is recognised and site protection policies are included in Local Plans and other strategic land-use plans.
- Produce regional guidelines on the requirements for lowland raised bog conservation, including issues of regional land use and drainage, in a wider landscape context.
- Where suitable alternatives exist, consumptive use of peat by central and local government and statutory agencies, including contracted work, should cease.
- Encourage community composting or anaerobic digestion facilities and promote use of these and other products as alternatives to peat.
- Seek to ensure all lowland raised bogs in
the UK meeting the JNCC guidelines for selection as SSSIs/ASSIs are notified. Through periodic reviews, ensure that the full natural and geographic range is maintained.
- Contribute to the implementation of relevant action plans for rare and declining species associated with lowland raised bogs in conjunction with the appropriate species steering groups.
- Develop and promote training on the conservation, management and rehabilitation of lowland raised bogs, targeting these at representatives from all key agencies, landowners and voluntary bodies.
- Encourage and provide advice on the development and marketing of peat alternatives to reduce amateur and professional demand for peat-based horticultural products, to achieve the long-term safeguard of peatlands.
- Encourage applications from potential partners to obtain funding to bring areas of lowland raised bog into favourable management.
- Develop links with European and international organisations and programmes to promote the exchange of information and experience in research, management techniques, and conservation strategies.
- Encourage the dissemination and use of ongoing and past research results, and commission further research where necessary, to improve understanding of the ecology of lowland raised mires. Key research topics will include vegetation dynamics and long-term vegetation change, hydrology (particularly inter-relations with regional water tables), palaeoecology and the ecology and management requirements of invertebrate communities and species.
- Produce simple, attractive information packages particularly aimed at capturing the interest and co-operation of site owners and managers towards favourable management.
- Generate ongoing information and publicity to encourage amateur and professional peat users to adopt alternatives, highlighting the threat to peatland conservation of continued peat use.