Enhancing improved grassland for wildlife
Small modifications to current practices in agriculturally improved grassland can provide significant benefits for wildlife.
Increasing the diversity of plant species and grazing at taller sward heights are two key ways to boost wildlife within productive grasslands. Simply including clovers and allowing some taller vegetation to develop through more lenient grazing or longer grazing rotations will boost insects. Good soil management that maintains high numbers of earthworms and other soil organisms is beneficial for nature and farming.
Semi-natural grasslands containing a rich diversity of native grasses and herbs are amongst our most special wildlife habitats. However, these habitats are scarce today, with most grassland being improved agriculturally to some degree. Improved grassland makes up more than a fifth of the UK land area. Small improvements across such a large area will provide considerable benefits for nature.
A grassland with a wide mix of plants brings agricultural benefits. Notably, it is more productive, resilient and beneficial to soil and livestock health.
Legumes provide the soil with free nitrogen, potentially fixing more than 100 Kg N/ha/yr from the atmosphere. Plants vary in how they extract nutrients and intercept light, so mixtures exploit these resources more efficiently. Thus, given the same growing conditions, swards with a higher diversity of plant species are more productive. Legumes and herbs have high nutritional value for livestock, increasing the protein and mineral content of the forage. Some also provide secondary dietary benefits, such as increased defence against internal parasites. A wider range of plant species provides some resilience to varying and extreme weather conditions, pests and disease.
An increase in the diversity of plant species and vegetation heights enhances the habitat for a whole range of wildlife including mammals, insects, amphibians and reptiles. Different plant species provide food for different insects.
Research has shown that even a small change from an intensive perennial rye grass sward to a grass and clover or grass-clover-herb mix can result in large increases in pollinators. In a mixed farming system, these pollinators can provide essential pollination in other areas of the farm.
Allowing some taller vegetation will benefit many insects including butterflies and grasshoppers, as well as birds such as yellowhammers and skylarks. It provides niches for insects to shelter, complete lifecycles and increases flowering opportunities for common wildflowers such as dandelion and clovers, providing more pollen and nectar for pollinators to feed on. Flowering dandelions also provide seed for adult and juvenile linnets and goldfinches.
Research has shown that grazing at 9-12cm had more than twice the number of larger insects than grazing at 6-9cm.
An increase in sward height and structure can be achieved through lenient grazing or having a longer break between grazing.
Maintaining an average sward height of around 10cm through the grazing season will allow plenty of opportunity for plants to flower. If rotationally grazed, ideally leave some patches of taller vegetation at the end of each grazing period. These guidelines will be easier to achieve with cattle but the general principles can be adapted for different grazing situations
Caution is required before reducing grazing on species-rich grasslands as wildflowers, insects and other wildlife already present are likely to be adapted to the current management regime. It is best not make too rapid or major changes on these grasslands – for more details see wildflower-rich pastures.
Enriching plant diversity
Legume-rich or mixed species mixes can be sown as short term leys (see advice on rotational legume and herb-rich swards) or as longer term grassland. Plant species need to be selected to suit the local conditions and planned management. Existing improved permanent pasture can be enriched by over-seeding with legumes or other herb mixes. Competition from the existing sward needs to be severely reduced (>50% bare ground).
If the grassland has not been re-seeded for many years, consider the potential for restoring wildflower-rich grassland.
Try to minimise the amount of topping. When topping is necessary, consider leaving some areas uncut or topping high to maintain some taller vegetation.
Apply herbicides in a targeted way where possible e.g. spot spraying or weed wiping.
Ground nesting birds such as skylark or breeding waders (eg curlew) can sometimes use improved grasslands. Avoid field operations that would impact these birds, such as harrowing and rolling, for the breeding period. Improved grasslands can also provide suitable habitat for corncrakes. If you are fortunate enough to live in an area with breeding corncrakes, please seek advice on appropriate management.
Here are some useful case studies and articles about how farmers are putting Farm Wildlife into practice on their farms
Author: Craig Dunton, Grey long-eared bat Project Officer, Bat Conservation Trust Species: Grey Long-eared bat: © Craig Dunton/www.bats.org.uk Why is farmland important for this species? With as few as 1000 individuals In the UK, the grey long-eared bat is one of our rarest mammals. Their distribution is restricted to the southern coast (Devon, Dorset, […]Read More