Grasslands vary tremendously in response to differences in soil type, the underlying rocks and water content, as well as their location in Britain and the type of management practiced. All these factors contribute to the diversity of plants and animals. In our most species-rich ‘unimproved grasslands’, which are scattered across the country, over 400 different species of flowering plants have been recorded. Some individual meadows can support over 100 species of plants on their own, though this is exceptional. Generally, species-rich grasslands will support between 20-40 species.
The colourful display from the white of meadowsweet, oxeye daisy, and pignut, the yellow of the cowslip and meadow vetchling, the blues of the devil’s-bit scabious and meadow crane’s-bill and purples of knapweed and orchids are a spectacular – if all but forgotten – sight.
Contrast this with the modern, improved pastures of the kind that now dominate the landscape. These may just contain just one or two plant species and are of little wildlife or scenic value.
Species-rich grassland is now a very uncommon habitat and the best examples, such as the Dartmoor site in the photograph above, have become extremely rare. Modern farming methods which use artificial fertilizers to improve yields (and often involve ploughing and re-sowing fields with very productive species) encourage the aggressive grass species, which then out-compete the native flowers and fine grasses that would otherwise support a plethora of wildlife. Conversely, lack of management can be equally damaging with brambles, bracken or tree saplings taking hold and eventually shading out the grassland until it disappears under woodland or scrub. Increasingly, road verges are becoming the main remaining good examples of species-rich grassland.
Grassland can be divided into 3 basic categories:
- Unimproved grassland – the product of traditional land management by our ancestors over many years, sometimes centuries. It is incredibly species-rich and has not been artificially fertilised, ploughed or reseeded.
- Semi-improved – improvement mainly by fertilizers in the past.
- Improved grassland – has a low diversity of species and has often been ploughed up and reseeded combined with heavy applications of fertilizer.
The following concentrates on what you can do to improve the wildlife value of improved and semi-improved grassland. Typical examples might be part of a local playing field or the grounds of a village hall. The management of existing areas of unimproved grassland can be quite complex and is not described here, though some of the links at the end of this section provide advice.
Community group involvement
There are two basic approaches that a local community can take to turn amenity or agricultural grassland into areas that are both attractive to wildlife and aesthetically pleasing: (a) basic changes to the present management regime and/or (b) taking deliberate action to increase the range of wildflowers present.
(a) Changes in management
The simplest, most dramatic and perhaps most effective management change is to allow an area of tightly mown grass to grow out. In effect, a management regime that mimics that of traditional hay meadows.
Simply leaving areas such as road verges, edges of parks and small areas in gardens uncut throughout the summer helps to provide cover for insects such as grasshoppers, crickets, butterflies (as well as small mammals such as voles and field mice) which in turn are food sources for birds. The seeds of the grasses and flowers are another excellent food source.
The timing of cutting is crucial and should be left until after the grasses and other plants have flowered and seeded – cutting after mid-July is probably best in Devon. Ideally, the cut material should be left to dry, raked up and removed so as to reduce the nutrient input back into the soil whilst allowing the seeds to drop. If possible, the aftermath (regrowth) should be grazed to keep scrub and dominant grasses from proliferating. Grazing may not be practical, but can be mimicked to an extent by a late summer/early autumn mow (with the clippings removed). It is often a good idea to leave some areas uncut as refuges for butterflies and other insects.
Some areas of existing grassland may already have quite a lot of wild flowers whereas others may just have a few highly productive species like perennial rye grass and white clover. As a rule, the greater the diversity of plants present, the greater the value to wildlife – there will simply be more types of food plant, more niches, and so on.
However, even a sward that has very few plant species can support a lot of wildlife if it is uncut during part of the spring and summer. By changing the physical structure of the grassland, and by allowing those plants that there are to flower and set seed, a wide range of invertebrates, birds and mammals can move into the area and thrive. And even a field of buttercups and dandelions can be very pleasing to the eye.
Do not fertilise grassland being managed for wildlife. It will encourage the domination of the sward by a few highly competitive species.
(b) Increasing the number of flowering plants
As well as changing the management, you can take action to increase the number of flowering plants that are present. Such grassland will be more attractive and support a greater wealth of wildlife.
To enhance grassland further, local wildflower seeds can be collected and scattered directly or grown on in pots and then transplanted. Please be careful, though, and do not take seeds from rare species; from nature reserves or Sites of Special Scientific Interest or without the landowner’s permission). Just take a few seeds from plants which are abundant. Seeds and young plants are also available from specialist suppliers and this may be the best means of acquiring wild flowers for your project. Try to find out what plants are appropriate to your local area and soil type – the links at the end of this section can help.
You may find that you have varying rates of success. Increasing the species diversity can be a long-term project. Indeed, getting a significant increase in the number of flowering plants may be impossible (or, at least, very expensive) if the area has been heavily fertilized and improved in the past. Elements such as phosphorus remain in the soil for a long time preventing the restoration of the natural balance. Creating a flower-rich sward in these circumstances may involve considerable effort and expense, including: removing topsoil to reduce fertility; preparing the soil and planting appropriate wild flower seeds, and controlling aggressive weeds. However, as explained above, any effort you do make, however small, is likely to be beneficial.
Some general considerations
Before deciding on your approach, there are a number of factors that you might like to bear in mind.
Firstly an assessment of the area can be carried out to identify:
- existing plants
- soil type and fertility
- aspect (north or south facing)
- past history of the land (has it been fertilized, ploughed, etc.?).
By identifying the existing plants, the site can be roughly categorized into:
- unimproved grassland – contains native fine leaved grasses and plants such as knapweed, birds-foot trefoil, sorrel, scabious and even orchids
- semi-improved – contains a mixture of fine leaved and coarse grasses and plants such as dandelion, plantain, yarrow and meadow buttercup
- Improved grassland – contains species such a perennial rye grass, docks, thistles, nettles and agricultural clovers.
Soil type and fertility go hand in hand with these categories. As a general rule, the more fertile the soil the less species will be found. Loamy, alluvial or clay soils are the most fertile and will often have been improved due to their agricultural productivity. Chalky, stony and even sandy soils are less fertile and therefore are more likely to support a greater diversity of species. Very steep fields, where the application of fertilisers is difficult, are often species-rich.
A sunny south-facing aspect is often considered best for grassland as most of the typical flowering plants thrive and it can benefit associated invertebrates, whilst a north-facing aspect is more likely to support a community of more shade-tolerant plants.