Lowland Calcareous Grassland BNG Units
High
Grassland
Trusted by Developers and Landowners
What is
Lowland Calcareous Grassland
Lowland calcareous grassland appears as a bright, open grassland with colourful flowers through spring and summer. This habitat is among England’s most species-rich grassland habitats. Rock roses, wild thyme, bird’s foot trefoil and orchids often create vivid patches across escarpments, dry valley slopes or old earthworks. The turf is fine textured, often aromatic, and sometimes interspersed with scattered scrub on the margins.
Why It Matters for BNG
For Developers
For Landowners
Where Are They Found?
Lowland calcareous grassland occurs on chalk and limestone geology across southern, central and eastern England. Escarpments, rolling dry valleys and older unimproved pastures commonly support this habitat. It persists where historic grazing has prevented scrub encroachment and where soils remain shallow and nutrient poor.
Soil and Site Requirements
This habitat requires shallow, lime rich soils with high pH and low nutrient levels. Chalk and limestone bedrock create the alkaline conditions that enable specialist plant species to compete. The soils drain freely and usually remain dry through summer. Avoiding artificial fertiliser, ploughing or reseeding is essential to retain habitat character.
How New Lowland Calcareous Grassland Is Created
Inputs
• Establish grazing to maintain short turf and prevent scrub encroachment
• Introduce native calcareous grassland species through seed or green hay
• Restore shallow, lime rich soils where they have been modified
• Manage nutrient levels to maintain low fertility
Management
• Apply controlled grazing to maintain varied turf height
• Retain areas of bare soil that support specialist invertebrates
• Remove invasive scrub or agricultural weeds that reduce species richness
• Avoid actions that increase soil fertility
Landscape
• Restore grassland on chalk or limestone slopes, terraces or old earthworks
• Connect separate calcareous patches to form larger habitat networks
• Integrate grassland with hedgerows and scattered scrub to create mosaics
Target Condition
Lowland calcareous grassland in its defined BNG condition should:
• Support a diverse mix of fine grasses and herbs typical of alkaline soils
• Present a short, species rich turf with varied sward structure
• Maintain low nutrient status with no dominance by coarse grasses
• Retain patches of bare ground for invertebrate specialists
• Avoid intensive agricultural inputs or soil disturbance
• Maintain grazing to prevent scrub encroachment and loss of diversity
The BNG Value of
Lowland Calcareous Grassland
• Distinctiveness: High, reflecting national and international rarity
• Condition Potential: High, where low nutrients and grazing maintain species richness
• Habitat Connectivity: Supports specialist invertebrates, upland butterflies and wide ecological networks
• Climate and Landscape Context: Contributes to resilient lowland landscapes and long term biodiversity targets
Species Typical of
Lowland Calcareous Grassland
Canopy or Primary Layer
• Sheep’s fescue (Festuca ovina)
• Quaking grass (Briza media)
• Upright brome (Bromus erectus)
Shrub or Secondary Layer
• Hawthorn (Crataegus monogyna)
• Guelder rose (Viburnum opulus)
• Dogwood (Cornus sanguinea)
Ground Flora or Understorey
• Wild thyme (Thymus polytrichus)
• Common rock rose (Helianthemum nummularium)
• Bird’s foot trefoil (Lotus corniculatus)
• Salad burnet (Sanguisorba minor)
• Dropwort (Filipendula vulgaris)
• Carline thistle (Carlina vulgaris)
• Bee orchid (Ophrys apifera)
• Pyramidal orchid (Anacamptis pyramidalis)
• Frog orchid (Coeloglossum viride)
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Frequently Asked Questions
Exploring Other Habitats?
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.
Upland Calcareous Grassland
Upland calcareous grassland is a springy, species-rich habitat occurring above approximately 250–300 metres on lime-rich, or “base-rich,” soils. The habitat develops as a short, species rich sward of calcicolous grasses, herbs and orchids adapted to alkaline conditions and cooler upland climates The grassland appears patchy and open, with fine grasses, colourful herbs and scattered rock outcrops. Wild thyme, common rock rose and bird’s foot trefoil often grow alongside sheep’s fescue and upright brome, creating a varied mosaic.
Upland Acid Grassland
Upland Acid Grassland is a mix of fine grasses, mosses and small herbaceous plants adapted to low pH and limited nutrients. This habitat appears as an open grassy landscape, often dominated by mat grass or purple moor grass. Texture and color come from all patches of tormentil, heath bedstraw and scattered mosses.
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