Areas of surviving natural grassland in lower fields are grass dominated, (largely Sweet Vernal-grass) with low herb content. Species recorded indicated an unimproved, neutral sward.
Backgound information to the Boothsdale grassland Project
History of Management
The absence of agricultural grass species, (such as perennial Rye-grass or timothy) suggests an unimproved sward.
Low herb content and dilapidated state of the surrounding hedges possibly indicate a history of grazing by sheep, although enquiries with local people suggest a more recent history of horse grazing. Local enquiries have also suggested the coincidence of horse grazing with the introduction of Himalayan Balsam. It is possible that Balsam seeds had been transferred from another site to Boothsdale on horse’s hooves but there is, as yet, no conclusive evidence to support this.
Previous herbicide treatments appear to have been more successful in killing off the original grass turf than the Balsam, leaving extensive areas of bare soil with dead or dying Brambles.In 2008 a program of hand pulling Himalayan Balsam before flowering was carried out and the uprooted plants composted in a non-sensitive area. However there is likely to be residual seed present in the soil even if there was a 100% successful pull. The seeds can remain viable in the seed bank for 2 years.
An ecological survey carried out in May 2008 identified the following species on site along with an indication of their abundance.
Grassland Management General
From an ecological viewpoint, management should maximise the opportunities for plants to flower and set seed and for as wide a range of invertebrates as possible to establish viable populations on the site. At the same time it should further the process of grassland establishment and prevent it from changing into scrub or woodland.
Virtually all grasslands in Britain require some mechanism to prevent succession if they are to remain as grassland. Traditionally three such methods all involving the removal of vegetation have been used; grazing, cutting and burning. Together with soil disturbance these methods form the basis of grassland management.
Sward species composition and structure are important to invertebrate fauna. Structure is important to grasslands birds and mammals.
Grassland Specific to Boothsdale
Left unmanaged for a long period Little Switzerland grassland has been colonised by species-poor swards of coarse grasses, scrub and tree saplings, consequently losing much of its conservation interest.
Initially management will be aimed at returning the site to a more desirable state through restorative management. A program of monitoring and surveying will be required. Results will determine ongoing management regime and timing of medium/long-term aim of switching to a maintenance management regime.
Restore, sustain and improve an area of unimproved lowland meadow grassland through the implementation of grazing.
Short-term: Restore Hedge boundary and secure with post and wire fencing. Carrying out minor arboriculture works alongside Eastern boundary where tree limbs are over-hanging grassland. Install permanent reliable water source. Implement grazing regime with Longhorn Cattle.
Medium term: Restorative management aimed at eradication of Himalayan Balsam and the reduction of tree and scrub species establishment.
Long term: Ensure ongoing prevention of tree and scrub species establishment. Switch from cattle, (restorative) grazing to sheep, (maintenance) grazing. Sustain and improve grassland sward.
Fencing was needed before grazing could be implement. The hedge was restored via replaning, laying and coppicing, during early 2009.
Grazing, (except at high stocking densities) is a gradual form of vegetation removal and is therefore less likely to cause large-scale irreparable damage than cutting, burning.
Different types of grazing animals differ in their grazing behaviour and selectivity. These also vary with age and breed. Grazing behaviour and selectivity will influence both species and structure of the sward. Grazing animals also differ in the nature and distribution of their dung and in their trampling intensity.
Grazing creates physical disturbance to the vegetation and soil. This is important in providing suitable conditions for germinating seedlings, especially annuals and for invertebrates that require bare, sparsely vegetated or disturbed ground. Most of the nutrients removed by grazing are returned to the grassland through the deposition of dung and urine.
A number of invertebrates feed on livestock dung and are very important in causing its breakdown and the recycling of nutrients it contains. Continuous Grazing – at low stocking densities this will tend to produce a mosaic of tall and short vegetation. Both overgrazing and undergrazing can lead to the loss of plant diversity and a decline in overall wildlife interest.
Grazing Risks and Opportunities
All grazing animals are to some extent selective in the plants that they eat. This selective defoliation will affect the species composition and structure of the sward. The overall effect of grazing will be to reduce the quantity of more palatable plant species, particularly tall herbs, and allow grazing resistant plants to become more frequent.
Although grazing can often be used with great success in restorative management, it is important to remember that most animals will only consume coarse herbage or browse scrub once more palatable vegetation has been exhausted. Hence it is often necessary to graze such areas very intensively for short periods.
It may become necessary to compartmentalise the cattle and graze on rotation. This can be done quite simply by containing them in specific fields. However, the risk of over grazing in smaller compartments is increased and close monitoring will be required to reduce such risks. Another option is to increase the number of livestock stock units, (lsu) grazing across the three separate fields. Both options entail similar risks and increased resources needed to run them
The smaller the compartment the greater the resources needed to run-it. High stocking rates are more likely to create a uniformly short turf with few flowers and will generally be poor for invertebrates especially at smaller sites with little natural sward variation.
Supplementary feeding will be avoided as it can result in poaching and localised enrichment due to dunging which can damage the sward, reduce plant diversity and introduce weeds.
Cattle – The Restorers
Cattle eat a wider range of the sward and are able to consume coarser herbage than horses and will feed on taller vegetation than sheep. Cattle feed by wrapping their large, rasping tongue around the herbage and cutting it between their lower teeth and upper dental pad as they swing their head. Their feeding technique and ability to knock down and open up tall vegetation makes them ideal for use on neglected sites.
They are selective in the patches of vegetation that they feed on, and this, together with their heavy trampling tends to produce an uneven sward consisting of patches of short and tall vegetation and disturbed and bare areas.The behaviour of cattle varies to some extent between breeds and particularly between different ages.
One of the largest and heaviest of the UK native breeds. Are docile with people and respond well to gentle handling. However, can appear intimidating due to large size and horns.
Due to horns, individuals generally graze further apart than some breeds. Care needed to provide plenty of space; a shortage may lead to disputes and possible injury from horns. A hardy breed maintaining good condition on rough pasture. They are well suited to grazing low quality swards, suiting a range of conservation sites. They are strongly grass based and readily consume a wide range of grasses. They are also willing to browse, even when good grazing is available.
Sheep – The Maintainers
Sheep are more selective feeders than cattle. They bite vegetation close to the ground and prefer short, fine swards to coarser herbage. Sheep grazing can therefore result in a combination of under and over grazing.
Sheep also cause very little trampling. This combined with grazing ability make them generally unsuitable for restorative management. Sheep are usually easier to handle and manage than cattle.
Why Not Horse and Ponies
Horses and ponies are normally undesirable as the sole stock on pastures. Horses and ponies can be very selective grazers and browsers, capable of completely eliminating individual plant species from a site.
Considerable care needs to be taken when introducing them to areas of botanical interest. Particularly in summer, horse and pony grazing can create a very short, botanically uninteresting sward interspersed with tall patches of unpalatable species such as Docks Rumex spp. and Common Nettle Urtica dioica. Such conditions are very poor for invertebrates. Moderate levels of horse grazing typically produce a mosaic of short, heavily grazed areas and coarse rank patches.Horses usually repeatedly drop their dung in the same area, causing problems of local nutrient enrichment.
Regular dunging areas are also avoided by grazing horses and ponies with the result that they often develop stands of rank, unpalatable vegetation such as Common Nettle Urtica dioica, thistles and Common Ragwort Senecio jacobaea.
Quadrat based monitoring will be used for the examination of the developing sward during different seasons. Appearance, relative growth rate, height, density, species composition and relative percentage cover will be monitored. By monitoring the developing sward the results can be assessed against the original objectives and the level of success evaluated. Ongoing monitoring will help determine decision making and how the management plan is periodically reviewed.