Grassland

Introduction

Grasslands are one of the most important and exciting wildlife habitats in the UK, supporting many specialist and often rare flowers, grasses, insects, fungi and birds. Grasslands occur where animal grazing or manual cutting prevents the bushes and trees invading and taking over. In some cases grasses are maintained by extreme weather conditions or unstable ground, but this is relatively rare.

The vast majority of our existing lowland grassland has been subjected to ploughing, reseeding and fertilisers and so is species poor. Only a small fraction (4%) of pre-war lowland grasslands have survived, managed in a traditional way, but these are often small and isolated. Ploughing of farmland with a loss of areas down to grass, reached its peak in Napoleonic times when the UK grain imports were reduced and self-sufficiency was key. Since then some former arable fields have returned to grassland with the signs of previous ploughing showing up as ridges across the ground, and on slopes the presence of terraces. Much older (“Celtic”) field systems can also been seen in this way with defunct field boundaries showing as ridges, particularly in the evening sunlight. For an in depth description of how our landscape has been influenced by previous human use, there is no better book than the highly recommended, classic work by the late Dr Oliver Rackham called “The History of the Countryside” – it’s a real eye opener.

Types of grassland

Grasslands are often classified as either acidic, neutral or alkaline according to the pH of the soil. The pH of the soil has a huge effect on the plant species present.

On the higher ground, such as upland moors and mountains in Wales, Northern Ireland and the more northerly half of Britain, the grasslands are extensive and usually acidic. The higher rain fall (which leaches the soil basic elements i.e. calcium, magnesium, sodium, and potassium that prevent soil acidity) and the underlying bedrock type leads to these being acidic. These support a different range of plants from their neutral and alkaline counterparts.

Although artificial fertilisers are often not used as they impractical to apply and would be washed away anyway, these grasslands are often so heavily grazed by sheep that they are significantly less rich than they could and should be.

The exception to uplands being acidic are the grasslands on limestone bedrock, such as the Yorkshire Dales.

In lowland grasslands are more likely to be neutral (especially in river valleys) or alkaline (such as the chalk downs). The exception are those on some sandy soils where the free drainage also leaches out the alkaline elements.

Many of the best sites are in Areas of Outstanding Natural Beauty and the very best are Sites of Special Scientific Interest and even National Nature Reserves.

It can be surprising why some important grasslands have survived to this day: one example is the extensive Salisbury Plain (“Salisbury Plain Training Area”) in Wiltshire which was taken over by the Government (i.e. the MoD) as a military training area – a process that started in 1897. It is used intensively by troops, fired on with shells and run over by armoured vehicles daily, but due to its size can cope and grassland can regenerate.

Alkaline grassland

Alkaline (also known as “calcarious“) grasslands can be found on chalk and limestone, and are fantastically and famously rich in plant and insect species where traditionally managed. Called “downland” when on chalk, from its dun-brown colour in summer, it is possible to find up to 40 different plant species in one square meter. In England a great chalk band runs from Dorset to the Wash. Limestone is characteristic of northern counties and dominates the Dales and the white Peak in Derbyshire and is just as varied, although some plants and insects don’t make it to the cooler north.

The soil is naturally low in nutrients and hence grass, especially if grazed, is not as dominant as it might otherwise be and this allows many flower species to establish.  The grazing only allows grasses and flowers that can tolerate being chopped off and can grow as short plants to thrive.  The level of grazing, and hence the length of the grass, greatly influences which flower and insect species can thrive.

It is still possible to walk over downland in spring and find spectacular shows of common spotted, bee, fragrant, pyramidal and lesser butterfly orchids, and in summer smell the powerful scent of thyme underfoot with blue butterflies searching for nectar and places to lay their eggs between the anthills. The sward is thick with other small and beautiful flowers such as cowslips, salad burnet, early gentian, stemless thistle, rock rose, fairy flax to name but a few.  Where the grassland is longer, black and greater knapweed and field scabious provide a breath taking show of purple flowers, often interspersed with yellow lady’s bedstaw. 

It is also a great hunting ground for plant and insect rarities.  How can you not love it?

This type of grassland is maintained through regular grazing by sheep and\or cattle, without which it quickly reverts to hawthorn scrub and then woodland.  Much of the diversity of such rich grasslands has been destroyed in many areas by the use of artificial fertilisers introduced in the 1970s. Those which survived were generally too steep or uneconomic to “improve”.  Although some remained where farmers resisted the need for change.

Traditionally sheep were grazed on downland during the day and then at night brought down to the arable fields where they were held in pens i.e. “folded”. Their dung then become a fertiliser on the fields.  In southern Wiltshire, for instance, many parishes are long a linear and were drawn up to follow this pattern of agriculture.  They comprise of downland, arable fields, flood plain pasture and then they stop at the river in the valley bottom.

Month	What’s in flower on chalk grassland
Apr	cowslip, Pasque flower, spring gentian, hairy violet
May	green winged orchid, birds foot trefoil, , salad burnet, fairy flax, common milkwort, bee orchid, common gentian, horse-shoe vetch, squinancywort, marjoram, oxeye daisy, meadow saxifrage
Jun	rockrose, lesser butterfly orchid, fly orchid, horseshoe vetch, small scabious, Cheddar pink, betony, tuberous thistle, clustered bellflower, bell flower, burnet saxifrage, meadow saxifrage, rest harrow
Jul	black knapweed, field scabious, yellow-wort, bastard toadflax, stemless thistle, round headed rampion, carline thistle, kidney vetch
Aug	greater knapweed, autumn gentian, clustered bellflower,
Sep	devils bit scabious, autumn lady’s tresses
Oct	devils bit scabious