The key features of dry acid grasslands are that they occur on nutrient-poor, acidic and highly porous soils, causing tussocky vegetation and bare ground to dominate. They are usually managed as pasture, and can commonly be found in parkland and as part of lowland heath landscapes.
Why are they important?
Acid grasslands are often found within a mosaic of habitats providing an important reservoir of specialised species, they declined in both number and wildlife value as a result of changes to agricultural practices.
Published figures for this decline vary significantly, but current estimates suggest the extent of acid grassland in England is 15,453 hectares.1
In 2017, GLNP habitat data includes 731 hectares of dry acid grassland amongst Greater Lincolnshire’s farmed landscape.2
Dry acid grassland varies greatly in appearance as well as in species richness. They can host heather and resemble lowland heath, or be parched and rich in lichens and bare ground.
Characteristic species include heath speedwell, heath bedstraw, sheep sorrel, common centaury, common stork’s-bill and biting stonecrop. Due to the low nutrient status some unusual fungi can also be found such as a variety of coral fungi species.
Bare sandy soils are a common component on acid grasslands. On southward sloping land receiving a lot of sunlight this provides excellent nesting habitat for some of our most important pollinators, including solitary bees.
Protected reptiles such as adder also thrive where there is bare, warm ground to bask in the sunlight. However, some nearby scrub cover is also an essential refuge from predation.
Wavy hair grass and sheep’s fescue and other tussocky grasses are another recognisable feature of this habitat. Contributing to structural diversity they offer feeding, nesting and refuge opportunities to a wealth of wildlife.
Changes to farming systems have seen many grasslands undergo agricultural improvement with the use of artificial fertilisers which reduce farmland biodiversity and the extent of acid grasslands.
Conversely, if unmanaged they can quickly lose species becoming rough species poor grasslands, or succumb to scrub encroachment.
Managing your acid grassland
There are a number of good practice management techniques for acid grassland, however the methods you choose will depend on various factors such as the size of your landholding and the time and resources you have available to you.
A key consideration is to maintain a mosaic of habitats. Ideally this should include a mixture of short turf and tussocky vegetation, small areas of scattered scrub and some bare ground.
Wherever possible, nutrient levels should be kept low as this helps to maintain a wide range of flowering plants. Application of fertilisers encourages the growth of highly competitive coarse grasses, lowering overall species diversity, and should be avoided.
Recommended management practice is to maintain dry acid grassland through light grazing. A rotational system will promote diversity and allow plants to flower and set seed. Using a variety of livestock which all have different feeding habits and preferences of vegetation will also achieve this. Grazing is generally conducted from July onwards in the year, encompassing most of the growing season to avoid the sward getting too long.
Small patches of birch, heather and other woody plants will add to the structural diversity of the site. However it is important to prevent encroachment. To help with this occasional grazing early in April and May can help tackle the spread of woody species. As grazing this early in the season may hinder the seeding of grassland plants it needs careful consideration.
Top management tips:
Graze established acid grassland from July to December
Keep nutrient levels low i.e. avoid application of artificial fertilisers
Keep control of scattered scrub with cutting as required
Top management tips:
Grazing may not always be a viable option, and in these circumstances grasslands can be maintained through cutting and removal to prevent nutrients from building up on site. Mowing in a weaving fashion will leave a mosaic of cut and uncut areas, maintaining structural diversity. If flowering plants that provide nectar sources are localised, consideration needs to be given to managing these areas separately to avoid loss of important species.
Plant species such as thistles and ragwort are often avoided by grazing livestock and can become the dominant vegetation in late summer when at full height and flower. If the site is grazed some weed control via cutting may be required at this time.