Other Lowland Acid Grassland BNG Units
High
Grassland
Trusted by Developers and Landowners
What is
Other Lowland Acid Grassland
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 Do They Occur?
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 Grassland
• 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 Grassland
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?
Open Mosaic Habitats on Previously Developed Land BNG
Open Mosaic Habitats on previously developed land are brownfield sites where disturbance, bare substrates, and early successional vegetation create a structurally diverse mosaic. The habitat supports specialised flora and invertebrates that depend on skeletal soils, bare ground, and pioneer plant communities.
The mosaic typically includes bare ground, ephemeral and short perennial vegetation, flower-rich open grassland, scrub patches, and occasional wet features.
Willow Scrub
Willow scrub is a transitional habitat dominated by native willow species, typically grey willow and goat willow, often with hawthorn, hazel, and dog rose. It forms in damp ground, at woodland margins, or on disturbed sites where scrub colonises freely.
The Willow scrub habitat is characterised by a mosaic structure: scrub cover between 10 and 60 percent with open grassland, wetland, or bare ground filling the gaps. A varied age structure, from seedlings to mature stems, supports higher condition scores. Ground flora is diverse where scrub remains open and light levels allow herbs and grasses to persist.
Upland Hay Meadow
Upland hay meadows are species rich grasslands dominated by a mix of fine grasses and abundant herbaceous wildflowers such as sweet vernal-grass, wood crane’s-bill, great burnet, pignut, and lady’s mantles.
These meadows have developed through long term traditional management that combines light grazing with a late summer hay cut. Rare species including lesser butterfly-orchid and burnt orchid are sometimes found.
This habitat is a dense mix of grasses and a wide variety of wildflowers, with no single grass species dominating the vegetation.
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