Lowland Dry Acid BNG Units
High
Grassland
Trusted by Developers and Landowners
What is
Lowland Dry Acid
Lowland dry acid grassland occurs on nutrient-poor, acidic soils, often sandy or gravelly. It supports a mix of fine grasses, mosses, lichens and small rosette forming herbs such as sheep’s sorrel, bird’s foot trefoil and mouse ear hawkweed. Grazing and light disturbance maintain the open mosaic structure that supports its characteristic species diversity.
Why It Matters for BNG
Creating or restoring acid grassland provides high value biodiversity units and strengthens heathland and grassland networks. It suits sites with acidic sandy or gravelly soils.
Maintaining low nutrient soils, grazing and scrub control enables landowners to generate BNG units from this scarce habitat with modest management changes.
Where Are They Found?
Lowland Dry Acid Grassland habitat typically occurs on nutrient-poor, free-draining soils with a pH between 4 and 5.5 and supports a characteristic range of grasses, herbs, lichens, and mosses. It is usually managed as a pasture. mainly in the warm, dry lowlands of southern England, including Breckland, the Suffolk Sandlings, the New Forest and Dorset and Wealden heaths.
Soil and Site Requirements
Lowland dry acid grassland forms on acidic soils with a pH of 4.0 to 5.5. Substrates are nutrient poor, free draining sands, gravels or acid rocks with shallow topsoils. Phosphorus and nitrogen levels must remain low. Compacted, heavily limed or fertilised soils are unsuitable.
How New Lowland Dry Acid Grassland Is Created
Inputs
• Allow natural colonisation where adjacent acid grassland is present
• Sow pioneer or nurse grass mixtures at appropriate rates
• Introduce green hay from local donor sites to supply seed
• Maintain low soil nutrients and control invasive perennial weeds
Management
• Apply managed grazing to maintain open structure
• Use controlled disturbance to support germination and diversity
• Avoid heavy machinery that damages fragile soils
Landscape
• Restore grassland close to existing acid grassland or heathland mosaics
• Use local green hay to retain local character
• Position creation where long term grazing management can be secured
How Existing Lowland Dry Acid Grassland Is Improved
Inputs
• Control scrub, bracken and invasive species
• Reinstate grazing where it has lapsed
• Remove nutrient enrichment where feasible
Management
• Manage grazing to maintain the open, species rich sward
• Adjust timing and intensity to retain diversity
• Monitor species richness and respond to declines
• Avoid neglect or overgrazing, both of which reduce condition
Landscape
• Restore adjacent land to strengthen grassland and heathland networks
• Break up encroaching scrub to reopen habitat structure
• Improve ecological connectivity across lowland heaths and acid grassland mosaics
Target Condition
Lowland dry acid grassland in its defined BNG condition should:
• Support high species richness, up to 25 species per square metre
• Maintain low nutrient status with no dominance by coarse grasses or weeds
• Show an open, fine grass structure with mosses, lichens and small herb species
• Demonstrate continuity of grazing or disturbance regimes
• Avoid scrub encroachment or nutrient enrichment that reduces diversity
The BNG Value of
Lowland Dry Acid
• Distinctiveness: High to Moderate
• Condition Potential: High, where management supports species richness
• Habitat Connectivity: Strengthens grassland and heathland mosaics and supports specialist invertebrates
• Climate and Landscape Context: Improves resilience in lowland heath and grassland systems and contributes to long term ecological networks
Species Typical of
Lowland Dry Acid
Canopy or Primary Layer
• Sheep’s fescue (Festuca ovina)
• Common bent (Agrostis capillaris)
• Wavy hair grass (Avenella flexuosa)
Shrub or Secondary Layer
• Heather (Calluna vulgaris)
• Bracken (Pteridium aquilinum)
• Gorse species, where encroaching
Ground Flora or Understorey
• Sheep’s sorrel (Rumex acetosella)
• Mouse ear hawkweed (Hieracium pilosella)
• Bird’s foot trefoil (Lotus corniculatus)
• Heath bedstraw (Galium saxatile)
• Mosses
• Lichens
.avif)
Frequently Asked Questions
What is Lowland Dry Acid Grassland?
A priority habitat found on well-drained, nutrient-poor, acidic soils (low pH), characterized by fine-leaved grasses (like fescues) and dwarf shrubs (like heathers).
How is BNG measured here?
Condition is assessed by the dominance of key indicator species (e.g., Wavy Hair-grass, Sheep's Fescue) and the presence of non-native/aggressive species.
How can I achieve BNG?
Enhancement through low-intensity grazing, management to reduce scrub/tree encroachment, or removal of nutrient-rich topsoil to expose underlying acidic substrate.
What is the BNG target condition?
A Good condition is defined by a high abundance of acid grassland species, an open sward structure, and a low cover of invasive/dominant species.
What management is required?
Grazing (often with sheep or cattle) is the key management tool. Cutting and removing cuttings can also be used to maintain the nutrient-poor conditions required by the habitat.
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.
Ready to buy your units?
Easily buy your BNG units online today to ensure compliance and positive environmental impact.