Keeping it rough
If we want to continue to see the beautiful barn owl or birds of prey such as the kestrel sweeping majestically across the High Weald fields, then there are real benefits in keeping and managing rough grassland. Rough and scruffy areas look far less appealing but are a valuable habitat in their own right.
What is rough grassland?
Rough grassland is a thick, matted, tussocky mix of native grass species. The grass has been allowed to grow tall in the summer and not cut or grazed and this will collapse by the autumn. Fresh green blades of grass will then grow up through it and by the following summer most of the first-year’s growth will have died-back and formed a “litter layer”. The photograph to the left (© The Barn Owl Trust) shows a good litter layer which is about 70mm deep – you can approximate its depth using the length of your index finger.
Benefits for wildlife - by keeping it rough?
The rough grassland is a perfect habitat for mammals such as the field vole, shrews and wood mice which are the main food sources for barn owls and birds of prey in the UK. Crops and hay fields may seem like a good alternative but only at certain times, permanent rough grassland provides them with food all year round. The success of the barn owl, at the top of the food chain, can therefore be used to establish the health and vitality of grassland habitats.
Grassland can also support protected and rare species such as adders, orchids and butterflies. Invertebrates also thrive in rough grassland as the insects and their eggs are better able to overwinter within the taller grass stems. Higher insect populations in turn lead to higher populations of mammals such as bats and shrews. For more information on the Benefits for other wildlife - the Benefits for Other Wildlife in Creating the Forgotten Habitat by Chris Speering.
Management of rough grassland
The most important aspect of managing rough grassland is not to disturb the litter layer which is the perfect environment for mammals, reptiles and invertebrates. However, grassland that is never cut or grazed will gradually become over-grown by brambles and scrub, and eventually trees, so some form of management is essential in the long term.
Here are some methods which will help you to maintain an area of rough grassland, encouraging an ecologically rich habitat all year round:
- Low density cattle grazing is often the best form of management. However it is important not to over-graze which would destroy the litter layer altogether.
- Topping the grass to a height of no less than 130mm every other year is an alternative method or small sites can be ‘topped’ using a brushcutter, strimmer or scythe.
- Another option is in late July or August to cut alternate strips across the field to a height of about 80mm. The following year, cut the other strips in the same way and so on, so each strip is cut every two years.
- The rough grass banks of drainage ditches should be cut alternately to a height of not less than 80mm.
- Areas next to hedges should be left to grow long and other areas mown once or twice a year, with the cuttings removed. This prevents a build-up of nutrients which causes coarser weeds to smother the more delicate wildflowers.
- Reducing the number of cuts has benefits for wildlife as well as delaying the cut until late summer. This allows plants to set seed and avoids conflicts with other wildlife interests such as invertebrates and nesting birds.
- The rough grassland should be ideally located 1-1.5km from a major road or motorway.
For more Rough grassland management advice, see How to manage rough grassland for barn owls from the Barn Owl Trust.
The return of the barn owl
Barn owls have seen a strong increase in numbers since 1995, however they can struggle to hunt in bad weather conditions as their soft feathers are not very waterproof in heavy rain, and being lightweight, they cannot fly well in very strong wind. So changing weather conditions such as increases in rainfall and more frequent windstorms can have an impact on the barn owl population.
Over the years there are have been several schemes to introduce barn owl boxes in appropriate areas across the High Weald - find out more in this 2009 article.