Lowland heathland is a very rare habitat - the UK has around 20% of the world’s resource. Heathland is characterised by heathers, which dominate the plant community, and also by acid grassland. Usually this is a very open habitat with a few scattered trees, areas of bare ground, gorse, and bogs and open water in wetter areas.

The Mendip Hills is a unique landscape made up of acidic sandstone and wind blown soil on a limestone ridge. This gives rise to ‘limestone heath’ where heather grows in tandem with limestone grassland. The best places to see this are Crook Peak, Wavering Down and Cross Plain, and Black Moor at Charterhouse. There are very few landscapes in the UK that can boast such a range of habitat in such close proximity.

Agricultural improvement has been a major cause of heathland loss. Lime has been applied to more acidic areas neutralising the pH to make the ground more suitable for growing crops and increase the productivity of pasture. Fertilisers are also used to boost growth encouraging grasses to out-compete the slower growing heather. Lack of management is also an issue.

Heathland is typically viewed as being un-productive, particularly for more commercial livestock. Over time, if heathland is not grazed or regularly burnt, it can progress from heather and gorse to scrub woodland, then to ash and birch woodland. In certain areas, heathland has been planted with conifers. The heather is shaded out by the tree canopy and the heathland is lost. Heath plants may still be present along woodland rides and by removing the trees it is often possible for these areas to naturally convert back to heathland.

Bracken can also be a problem as its fronds can shade out young heather seedlings.

Heathland is best managed with a ‘light’, extensive grazing regime that helps to maintain a varied species composition and structure. It ideally should be composed of heather and western gorse of different ages, allowing insects and birds to use different stages in the growth of these plants.

For example, birds may eat the bilberry seeds produced by middle-aged plants, but prefer to nest in the centre of older, bushier plants.Grazing helps to maintain a varied structure and is best carried out by traditional cattle breeds such as White Park, Red Devon and Dexter, or by hardy Exmoor and Dartmoor ponies that are kept outside throughout the winter.

Large livestock help to control bracken as they knock over the fronds and damage the roots, thereby weakening the plants. Livestock eat young scrub seedlings which controls scrub encroachment on heathland.

There are three heathers present in the Mendip Hills, heather (ling), bell heather and cross-leaved heath. All of them grow on acidic soils. With fine leaves and purple flowers between July and September, each species has its own individual characteristics.

Heather has relatively small flowers in dense groups along branches. Bell heather has larger flowers which are slightly crimson-purple. This species prefers dry heathlands which have very acidic soils compared to heather which can grow on less acidic soils. Cross-leaved heath has leaves in crosses along its branches and a dense group of rose-pink flowers at the end of the branch. It prefers wet acidic soils rather than dry heaths.

All of these species are important for nectar gathering insects, especially bees producing heather honey.

Bilberry is a broadleaved scrub species known for its edible black berries. Also known as whortleberry, it is an important food source for many heathland birds like the nightjar and skylark.

There are few heathlands on the Mendip Hills which are large enough to support nightjars, but they have been heard on Black Down Common.

Western gorse is very similar to its more common sister species, European gorse. It is a spiny plant growing to a metre in height and is impenetrable if allowed to develop into a dense stand.

Its yellow, coconut scented flowers appear from July to September.

Purple moor-grass is a perennial plant that dies back to a mound of dead leaves during the winter. If this grass is not managed regularly it can form tussocks up to 120cm high which can make future management difficult.

Livestock will eat the new growth, but not the dead leaves and cutting can damage machinery.