“Explaining to the general public and to conservation volunteers why conservation often involves altering the environment.”

The UK has many diverse and varying habitats, but over time these habitats and the species within them come under threat.  If a habitat is left undisturbed for a long period of time, it undergoes a process called succession. This is when a habitat naturally changes from one ecosystem to another. For example, on heathland, over time trees and scrub can begin to grow from seeds naturally being blown over the area. As the trees and scrub spreads, they shade natural flora and can eventually change the composition of the soil so the native flora can never grow back. Succession, therefore, needs to be managed to keep the variety and diversity of habitats and species.  

                Succession can be managed in a number of ways, such as coppicing and complete woodland clearance, to cattle or livestock grazing. All of these things involve altering the environment, but in a good way, a way that prevents important habitats from being lost to succession. An example of this can be seen at Lincoln’s Couth Common. Scrub has started to grow around the common and is shading the natural grassland. This scrub is being cut back to keep the grassland in its natural state.

                Invasive species also need to be managed, for example, Rhododendron plants. Rhododendron is very invasive and spreads very quickly. It then shades natural flora and the fallen leaves acidify the soil, therefore prevent plant regeneration as the soil composition has changed. Invasive plants like this need to be cut away and destroyed before they have a chance to permanently change the soil composition. This is being done at Swanholme Lakes in Lincoln, where Rhododendron and Birch trees are being cut down and burnt to allow the natural heathland to regenerate.

                Coppicing is a traditional woodland management practice which involves cutting sections of woodland on a regular cycle. The timber produced can be used for fencing and fuel. Once the trees have been coppiced there is a clearing. This allows warmth and light to reach the ground, allowing plant and insect life to flourish and biodiversity increases. Over the years the trees re-grow with many stems and will eventually block out the light again, therefore the coppicing needs to be carried out regularly. Coppicing is being done on Marley Common, in West Sussex. It is an area of lowland heath that is being invaded by chestnut trees, as well as others such as birch. Areas of Chestnut are being coppiced to allow sunlight and warmth to the ground, so the natural flora has a chance to regenerate.

                Cattle grazing is also an effective way of managing succession, especially in heathland. Grazing increases plant species richness and reduces leaf litter depth and the cover of dwarf shrubs and scrub species (Bullock et al 1997). Seeds will also get spread in their droppings, spreading the diversity of plant life. They also spread nutrients from one place to another. Grazing does not prevent tree encroachment however, but free-range grazing combined with tree cutting are suitable for management of species-rich heathland with grass-heather mosaics (Bokdam et al. 2000). Grazing reduces the dominance of strongly competitive grasses and allows the more delicate heathers and flowers to flourish, leading to a more open landscape and a variety of micro-climates.

The Cotswold Grazing Animals Project aims to restore, conserve and enhance flower-rich limestone grassland in the Cotswolds. This area is made up of many kinds of lime-loving flora, as well as a variety of insects and birds, and over half of the remaining grassland is protected by SSSI’s or National Nature Reserves. The decline in habitat is due to the intensification of farming by conversion to arable land and ploughing and re-seeding with vigorous grasses. A lack of grazing allows coarse grasses to dominate; swamping low-growing grasses and herbs and eventually the habitats is lost under trees and scrub.  The cattle have been introduced to get back the old, rare limestone grassland.

                Other ways of positively altering the environment is creating habitats, such as ponds. Pond creation encourages threatened species, such as newts, and creates wetland habitats for many other species. A range of depths also encourages waterside plant life, which provides cover for wetland species as well as many others such as birds. The South Yorkshire Ponds Project aims to restore dried out or silted up ponds to benefit wildlife and they are also conducting pond surveys. A Lowland Pond Survey was carried out in England, Wales and Scotland by Pond Conservation in 1998. The aims were to estimate the number of ponds in lowland Britain and to provide and estimate of pond ecological quality in terms of biodiversity. They found that ponds are very important for biodiversity. Almost half of British wetland plant species, including uncommon species, were found in the ponds. Nearby intensive land use has an impact on the biodiversity of the pond. New ponds have a high conservation value and are home to a wide variety of wetland plant species and are less likely to be effected by nutrient enrichment.

                Sometimes a habitat is altered so convert it back to its pre-agricultural state. This is called re-wilding. It includes such things as grazing and creating wetland habitats by blocking drainage routes, as well as planting woodlands and hedgerows. Planting trees and allowing some succession around previously agricultural areas encourages the local plant life to grow back and local species to return.

                Re-wilding is also a part of the National Trusts “Living Landscape” project. This is a project to re-connect and revitalise remaining species rich habitats all over the country. Agricultural areas are undergoing re-wilding to encourage species back, and then they are being reconnected to other spaces in rural and urban areas by natural corridors, to allow the movement of species to other areas of the country. An example of this is the Great Fen Project. This project aims to restore wetland between Huntington and Peterborough and reconnecting habitats. The area is first restored by cutting back scrub and trees to connect the open habitats of Woodwalton and Holme Fens, which will enhance the value of the site. The two habitats will then be joined to remove the arable barrier for less mobile invertebrates and plants. This will also provide more space for habitats and species and will allow a network of paths and waterways to be developed, and will create one of the largest nature reserves in England. The reserve will then be expanded further and visitor centres and other infrastructure will be developed.

                Another form of habitat management which alters the environment is controlled burning. Controlled burning is an ancient practice commonly seen in heath land.  It promotes the regeneration of seeds. It also prevents the spread of trees and scrub that encroach due to succession. It is also undertaken in woodland and forests and can be done periodically to avoid bird nesting times. Period fire favours understory species that require more open habitats. A mosaic of burned and unburned areas maximise the “edge effect”, which promotes a large and varied wildlife population. It also stimulates fruit and seed production and increases the amount of browse material for species such as deer (Wade, D et al 1989).

                The New Forest National Park use controlled burning on their heathland to maintain gorse and scrub. These plants would quickly shade out and replace highly valued heathland plants and animals if controlled burning was not used to manage it. Rare species such as the Dartford Warbler rely on the rotational burning of gorse to produce the dense growth the like. Controlled burning in the New Forest revitalises plants on the heath by removing old growth and allowing nutritious young plants to re grow for grazing. It also provides thick cover for nesting and shelter.

                Habitats can be managed and maintained in a variety of ways as I have shown. These management techniques all involve altering the environment, but they do so in a way that promotes biodiversity and healthy habitats.

References

Bokdam J, Gleichman J.M (2000) Journal of Applied Ecology 37(3):415-431. Effects to grazing by free-ranging cattle on vegetation dynamics in a continental north-west European heathland.

Bullock J, Pakeman R (1997) Biological Conservation 79(1):1-13. Grazing of lowland heath in England: Management methods and their effects on heathland vegetation.

Wade D, Lunsford J (1989) A Guide for Prescribed Fire in Southern Forests. USDA Forest Service.