Chalk grassland habitat | Photographing Wildflowers

Lowland calcareous grassland

Another name for chalk grassland is lowland calcareous grassland. I’m writing a page about it because it’s central to my interest in UK wildflowers as there is such a profusion of flora that can be found in this habitat! I live on the chalky South Downs, but some of my trips away have been to areas of chalk grassland too: Buxton in Derbyshire and Les Andelys in Normandy France.

chalk grassland sussex — Chalk grassland in Sussex – the Seven Sisters cliffs in the South Downs National Park with Thrift flowers

A profusion of flowers

One of the defining features of chalk grassland is the sheer number of wildflower species to be found in a given area. Typical plants to be found in such places include Milkwort Polygala, Eyebright Euphrasia, and Cowslip Primula veris. But finding any one of these doesn’t indicate a chalk grassland habitat. A successful chalk meadow will include a few such plants together. For example in the main pic at the top of the page I can see Clustered Bellflower, Viper’s Bugloss, Hawkbit, Self-heal, Hedge Bedstraw, Lesser Knapweed and Red Bartsia in flower.

According to Plantlife:

Some of our most spectacular of all wild flower habitats can be found on
well drained, alkaline soil that develops on top of chalk and limestone
rocks. Chalk downland and limestone grassland can support an
astonishing 50 species in a single metre square, with wild thyme, lady’s
bedstraw, salad burnet, common rockrose, marjoram, harebell and small
scabious densely packed together. But it’s the rare and unusual flowers
that make these meadows so exciting: the chance to find all manner of
orchids, gentians, milkworts, vetches and pasqueflowers.

I think that quote explains my love for this habitat: the variety of species plus the chance to find something unusual.

How chalk grassland habitat was formed

Chalk grassland is not a fully natural habitat. These areas have been grazed for centuries, which has shaped the grassland ecology. Up until the first world war, sheep grazing was the most common type of farming on the South Downs. During both wars, more and more land was ploughed up in an effort to feed the country. The only remaining unimproved grassland these days tends to be on steep slopes, thin soils and places where arable farming would not be profitable. Some areas are still grazed but others not. The grass in the top picture is kept short by rabbits.

However, grassland needs grazing, and many Wildlife Trusts and other land management teams are implementing the use of sheep and cattle to try and restore the balance. Keeping the grass short is not the only benefit, a muddy hoof may also happen to plant a wildflower seed. Meadows may also be cut by machine following a schedule that maximises the plant diversity.

Unimproved grassland

The phrase unimproved grassland means that the area is semi-natural and has not been reseeded, fertilized, or ploughed. It’s the result of traditional land management practices over many years. If the grasses receive too many nutrients, they can grow strongly, out-competing the delicate wildflowers.

The semi-parasitic Yellow Rattle Rhinanthus minor is sometimes used to reduce the dominance of grasses within a habitat. For example you might find it in a wildflower seed mix. It’s pretty in its own right but also keeps down the grasses.

Chalk grassland indicator species

Eyebright Euphrasia Seaford Head Seven Sisters Aug 2021 — Eyebright – *Euphrasia* – Seaford Head Seven Sisters – Aug 2021

I have mentioned chalk grassland indicator species before in posts about the area of the South Downs National Park just west of Eastbourne. When we were helping with the chalk grassland assessment of this area, we were given a tick list of the following species:

Bird’s foot Trefoil – Lotus corniculatus
Carline Thistle – Carlina vulgaris
Common Rock Rose – Helianthemum nummularium
Cowslip – Primula veris
Dropwort – Filipendula vulgaris
Devil’s-bit Scabious – Succisa pratensis
Eyebright – Euphrasia
Fairy Flax – Linum catharticum
Field Scabious – Knautia arvensis
Gentians – including Gentianella amarella
Greater Knapweed – Centaurea scabiosa
Hairy Violet – Viola hirta
Kidney Vetch – Anthyllis vulneraria
Lady’s Bedstraw – Galium verum
Marjoram – Origanum vulgare
Milkwort – Polygala vulgaris
Mouse-ear Hawkweed – Pilosella officinarum
Orchids
Ox-eye Daisy – Leucanthemum vulgare
Restharrow – Ononis repens
Rough/Lesser Hawkbit – Leontodon
Salad Burnet – Sanguisorba minor
Small Scabious – Scabiosa columbaria
Squinancywort – Asperula cynanchica
Stemless Thistle – aka Dwarf Thistle – Cirsium acaule
Wild Basil – Clinopodium vulgare
Wild Thyme – Thymus polytrichus
Yellow-wort – Blackstonia perfoliata

How we surveyed the site

We were surveying twenty quadrats across a field, (chosen beforehand to avoid selection bias in situ) at intervals along a W-shaped walk, each quadrat being approximately a square metre. A flower was considered Frequent if it appeared in nine or more quadrats, Occasional in five to eight, and Rare if less than that. In a biodiverse quadrat we might spot ten or more of the above species in leaf or flower. A field was considered to meet the target if there were two or more Frequent species (F=>2) and six or more Frequent plus Occasional (F+O=>6).

Undesirable species for chalk grassland

Don’t forget the undesirable species – too many of these and your habitat will soon become degraded! When out on the Downs we also notice the encroaching nature of scrub, brambles and Traveller’s joy Clematis vitalba. Scrub does provide shelter for birds and insects however.

Broad-leaved Dock – Rumex obtusifolius
Curled Dock – Rumex crispus
Creeping Thistle – Cirsium arvense
Common Ragwort – Senecio jacobaea
Common Nettle – Urtica dioica
Tor Grass – Brachypodium pinnatum

Biodiversity supported by chalk grassland

Marbled white butterfly spear thistle cirsium vulgare south downs jul 2024 — Marbled white butterfly on Spear thistle *Cirsium vulgare* – Gayle’s Farm South Downs – Jul 2024

You probably already realise that plants are my thing, but even as a wildflower spotter, I understand that the greater the biodiversity of wildflowers, the greater the biodiversity of insects such as butterflies and moths, and the birds and other animals that can be supported. Not only that, but according to the charity Plantlife (see above link) flower-rich grasslands and meadows can store 500% more carbon than fields of pure grass.

An article by the charity Butterfly Conservation explains that many of the flowers listed above are caterpillar food plants. They provide a list of butterflies and moths that might be found in chalk grassland including Marbled White and Common Blue which even someone like me with a passing knowledge can attest to. Other specialists may include species of spiders, bees and beetles, and I often see Skylarks overhead.