RSPB’s ‘Ark in the Park’ research project found that long grass had a lot more seeds and invertebrates than short grass, benefiting birds and mammals.
An advice note on Managing Amenity Grassland can be found via a link on this RSPB page.
More amenity grassland links
Floralocale: grassland management and restoration
Management of amenity grassland for wildlife.
There are many opportunities in parks and green spaces to create more varied grassland, for reducing the total area of closely mown grass, and, for areas not required for sports and recreation, making more meadow-like areas with longer grass. Mowing can be done on a rotation, creating areas with grass of different lengths.
Regular mowing to keep the grass short does not necessarily banish wildlife and plants of interest completely. However to keep some biodiversity interest, the use of fertilisers, pesticides and herbicides should be reduced to a minimum or indeed stopped.
Grass cuttings from longer grass should be removed to prevent underlying plants being smothered, with soils becoming too nutrient-rich.
If areas of nutrient rich grass are left unmanaged they will rapidly become overgrown with a few dominant species of tall grasses, docks, brambles, thistles etc which will need to be controlled.
When cutting, it is important to allow wildlife to escape and to keep some cover nearby to provide protection from predators. Grass cuttings can be heaped to allow invertebrates and other wildlife a refuge.
Good nectar sources can be provided in adjacent flower and shrub beds and wildflowers can be encouraged to grow and seed within the grass by mowing less often.
Areas of undisturbed grassland with long grass maintained over the winter, are really beneficial for wildlife. Some such areas may be mown in rotation only every two to three years. Areas where this can be done are more likely to be on the edges of sites, next to informal shrubberies or hedges, or in places where people do not normally go.
In these wilder areas of long grass it is best to maintain a ‘managed’ look by mowing a 1-2 m strip of short grass between any paths and the longer grass. People can also be kept ‘on-side’ by telling them of the benefits of longer grass for wildlife through informative signs.