The use of herbivores to manage sites for nature conservation purposes is now widespread. In this article, Kate Priestman finds out more…
The British landscape has evolved hand-in-hand with ‘keystone’ species; our woodlands, meadows, heathlands and grasslands have been shaped by the grazing patterns of large herbivores such as red deer and native ponies. The ecological balance of herbivores within habitats was kept in check by natural predators, allowing plant species to thrive and shift with the movement of herbivores through the landscape.
The increase of human influence upon the natural world saw the gradual displacement and substitution of these wild grazers with domestic animals, such as sheep, cattle and pigs. As herd size increased and management changed, the need for grassland also increased and other habitats such as woodland became less utilised for their resources. These changes have led to problems of overgrazing and compaction of grassland and upland habitats, and a decrease in woodland biodiversity, culminating in an overall loss of habitat and species diversity.
Conservation grazing seeks to bring balance back to those habitats that have become impoverished. Through the careful selection and management of large grazers, natural regeneration is encouraged by virtue of their particular grazing traits. Balanced grazing – using the right species, at the right density, at the right time – reduces the prevalence of vigorous plants that outcompete more ‘fragile’ species; creates microclimates and areas of bare ground through trampling and disturbance; and by virtue of these influences, increases diversity. As an added bonus, dung is a valuable resource for certain invertebrates. The increase in diversity of plant species and niches has a knock-on-effect for animals such as butterflies, bees, bats and birds. There is also a cultural benefit to conservation grazing by virtue of the livestock that is selected for this purpose – native and rare breeds are favoured due to their hardiness and ability to cope well with unimproved grassland.
Grazer Selection
It is important to carefully select the right animal and breed of animal for the conservation aims and conditions of a site. Feeding preferences, physiology and behaviour mean that different animals and breeds are suitable for managing different habitats. An overview of the pros and cons of different types of animal for conservation grazing is illustrated in the following examples:
- cattle wrap their tongues around vegetation and pull it up in tufts, which creates an uneven sward in terms of length and a tussocky finish. They are good at pushing their way through scrub and creating open areas, in addition to eating longer and coarser grasses. They are considered preferable to sheep and horses when improving a habitat for invertebrates. However, their size means that their presence can lead to undesirable levels of trampling and poaching if not managed carefully;
- sheep are useful in areas that can’t be accessed by larger animals. They do need to be used with some caution as they can select flower-heads to eat, which may not be advantageous for certain conservation schemes. Sheep tend to nibble shorter grasses, they are good for the control of scrub and are easy to handle;
- goats can be useful for scrubby areas where they will happily eat willow, gorse, ash and guelder-rose;
- ponies select grasses to eat and generally leave flower-heads alone. They graze the vegetation to a very low level. Like cattle, they can cause problems through over-trampling and poaching. Ponies are nutritionally adapted to graze on unimproved, species-rich grasslands, which is seen as their main advantage.
In addition to the above, animals such as red deer and water buffalo are also used effectively for conservation grazing; often a combination of different species is used to create desirable conditions.
Conservation grazing is not just restricted to grassland and heathland habitats, it is also an important component of woodland management. Animals such as pig, boar and deer are useful grazers under these conditions.
Other Considerations
Depending on the type of habitat, the aim of the management and the chosen animal and breed, stocking levels and timing of grazing need to be carefully considered; for example, grazing over the winter months may be preferable on light, well drained soils where productivity is low (i.e. chalk and limestone soils). Year-round grazing can be undertaken; however, it is important to select the right level of stocking density for the habitat type.
Application
Conservation grazing is now a widespread management method and many conservation bodies regularly use grazers to improve and maintain the sites that they manage for biodiversity. Cheshire Wildlife Trust, for example, has become a leader in conservation grazing. The Trust manages one of the largest native-breed longhorn herds in the UK and over 300 Hebridean sheep, who look after wildlife sites throughout the north-west; this accounts for more than 500ha of land, including grassland habitats on 22 nature reserves, in addition to land managed by the RSPB, National Trust and Lancashire Wildlife Trust. The Trust also works with a number of local landowners.
The National Trust use a herd of belted galloway cattle to manage Cotswold grassland. The low-intensity grazing provided by the cattle have enabled a shift from grass to herbs, with plants such as marjoram, thyme, vetches and rare orchids growing up. This has resulted in an increase in butterflies and beetles, creating a rich habitat for flora and fauna.
Advances in research with regards to conservation grazing in recent years, has enabled this type of management to be honed even further, increasing its effectiveness and resulting in greater wins for biodiversity.
References:
- National Trust – Conservation Grazing
- Cheshire Wildlife Trust
- The Wildlife Trusts
- Grazing Animals Project
- The Woodland Trust – Conservation Grazing in Woodland Management, 2012
About the Author: Kate Priestman (CEnv, MCIEEM) has over sixteen years experience as an ecologist. Prior to setting up her own consultancy business in 2012, Kate worked in London for over a decade, providing the lead ecology role for a number of high profile projects. Kate works as an artist, writer and editor.
