Other Lowland Acid Grassland BNG Units
High
Grassland
Trusted by Developers and Landowners
What are Other Lowland Acid Grasslands?
Other Lowland Acid Grassland (OLAG) is a species-poor to moderately diverse acid grassland found on low-fertility, acidic soils in lowland areas. This habitat develops as a short, species rich sward of fine grasses, herbs, mosses and lichens adapted to low pH and low nutrient availability. The habitat appears as a low, even turf with small flowering plants scattered through the grassland.
Why It Matters for BNG
OLAG contributes high distinctiveness units where acidic soils occur. Its species richness supports strong biodiversity outcomes in lowland mosaics.
Low intensity grazing and nutrient control allow landowners to produce high value BNG credits on existing or restorable acid grassland.
Where You'll Find It
Other Lowland Acid Grassland (OLAG) occurs on acidic sandy, gravelly or peaty soils in lowland areas. It often appears on remnant grasslands, commons, heathland fringes and historic pasture that has avoided intensive improvement. These sites frequently form part of wider lowland mosaics with heath, scrub and open woodland.
Soil and Site Requirements
This habitat requires acidic soils with a pH below 5.5. Substrates include sands, gravels and shallow peaty deposits. Low nutrient conditions are essential, and drainage should remain natural. Avoid fertiliser, lime or soil enrichment, which would shift the habitat away from its characteristic species.
How Other Lowland Acid Grassland Is Created
Inputs
• Restore acidic, low nutrient soils through appropriate soil management
• Introduce native acid grassland species through seed mixes or green hay
• Remove invasive plants and early scrub to protect establishment
• Allow natural colonisation where nearby acid grassland exists
Management
• Apply low intensity grazing or periodic cutting to maintain short turf
• Retain some bare ground for invertebrates and small herbs
• Prevent scrub encroachment through regular control
• Maintain soil acidity by avoiding nutrient enrichment
Landscape
• Restore OLAG within wider mosaics of heathland and semi natural grassland
• Connect scattered acid grassland patches to improve ecological networks
• Position restoration in areas with existing acidic substrates or historic grassland
How Existing Other Lowland Acid Grassland Is Improved
Inputs
• Remove scrub and bracken that suppress characteristic species
• Reintroduce missing herbs, grasses and lichens using appropriate seed sources
• Restore soil acidity where nutrient enrichment has occurred
• Maintain natural drainage and avoid soil disturbance
Management
• Use controlled grazing to keep the sward short and species rich
• Adjust cutting or grazing to maintain structural variation
• Monitor moss and lichen layers to ensure low nutrient conditions persist
• Prevent succession to heath or woodland where inappropriate
Landscape
• Expand OLAG into adjacent land with suitable soil conditions
• Improve continuity with nearby heath, scrub or semi natural grassland
• Retain open, connected habitat important for specialist invertebrates and birds
Target Condition
Other lowland acid grassland in its defined BNG condition should:
• Support fine grasses such as sheep’s fescue and common bent
• Contain herbs such as tormentil, heath bedstraw and bird’s foot trefoil
• Maintain low nutrient, acidic soils with pH below 5.5
• Present a short, species rich sward with patches of bare ground
• Retain mosses and lichens typical of acid grassland
• Avoid dominance by scrub or coarse grasses
The BNG Value of Other Lowland Acid Grasslands
• Distinctiveness: High
• Condition Potential: High, where low nutrient conditions and grazing maintain diversity
• Habitat Connectivity: Strengthens lowland mosaics of heath, scrub and woodland
• Climate and Landscape Context: Supports resilient lowland ecosystems and specialist invertebrates
Species Typical of Other Lowland Acid Grasslands
Canopy or Primary Layer
• Sheep’s fescue (Festuca ovina)
• Common bent (Agrostis capillaris)
• Red fescue (Festuca rubra)
Shrub or Secondary Layer
• Occasional heather (Calluna vulgaris) in mosaic areas
• Sparse dwarf shrubs where OLAG merges with heathland
Ground Flora or Understorey
• Tormentil (Potentilla erecta)
• Heath bedstraw (Galium saxatile)
• Bird’s foot trefoil (Lotus corniculatus)
• Harebell (Campanula rotundifolia)
• Heath speedwell (Veronica officinalis)
• Mosses including Cladonia and other acid tolerant species
• Lichens on open soil and dry turf
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Frequently Asked Questions
What is Other Lowland Acid Grassland?
A general BNG metric category for acid grasslands that do not meet the criteria for the priority Lowland Dry Acid Grassland, often due to degradation or management.
How is BNG measured here?
Similar to the priority type, but the distinctiveness is lower. Condition is scored by the presence/absence of key species and soil characteristics.
How can I achieve BNG?
Enhancement by changing management to mimic traditional grazing/cutting regimes, focusing on reducing nutrient levels and controlling scrub/bracken.
What is the BNG target condition?
The goal is typically to enhance it towards a Good condition of the priority Lowland Dry Acid Grassland through multi-year management.
What management is required?
Management must be focused on reducing nutrient inputs and maintaining the open sward structure through grazing or cutting and removal.
Exploring Other Habitats?
Arable Field Margins Pollen and Nectar
Arable field margins pollen and nectar are grass margins around arable fields sown with wildflowers and legumes managed specifically to provide pollen and nectar resources for invertebrates. The mix must include at least four nectar-rich flowering species and the margin is kept low-input and rotationally cut to maintain flowering through the season. The arable field must remain in a crop rotation including an arable crop.
Unlike wild bird seed margins, the management objective here is flowering continuity for pollinators rather than seed retention for birds. This habitat type sits within the Cropland broad habitat in the BNG metric and is classified separately from tussocky margins, cultivated margins and game bird mix.
Arable Field Margins Game Bird Mix
Arable field margins game bird mix are margins, strips, blocks or corners around arable fields sown with wild bird cover crops and left unharvested over winter so that seed produced by the plants remains available to farmland wildlife. The arable field must be in a crop rotation that includes an arable crop, such as wheat, barley, maize or oats, even if in certain years the field is in temporary grass, set-aside or fallow.
Mixes typically combine seed-bearing cereals, brassicas and oil-rich crops to provide food through the winter hungry gap and standing cover for gamebirds and declining farmland bird species.
Arable Field Margins Cultivated Annually
Arable field margins cultivated annually are strips along the edges of arable fields, typically 2–12 metres wide, managed under a low-input regime to support annual arable plants. They are lightly cultivated each year, usually in late summer or autumn, without herbicide or fertiliser, creating the open, disturbed soil conditions that annual arable flora requires to germinate.
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