Managing Cannock Chase

Over the last 60 years a wealth of research has been carried out into the ecology and modern management of lowland heathlands. This section outlines some of the more recent research into the benefits of grazing as an effective conservation management tool.

Bokdam & Gleichman (2000) studied six heathland types in the Netherlands with different nutrient levels. In the first five years, grazing significantly increased species diversity in all habitats, then mostly stabilised over the next five years.

They concluded that free-ranging grazing combined with tree cutting is an effective way to maintain species-rich, open heathlands with a mix of grass and heather.

Buttenschøn & Buttenschøn (2015) studied five Danish sites grazed for 15–40 years. They recommend grazing for heaths in good condition, and grazing plus mowing for restoration sites. At a pressure of 0.35–0.6 livestock units per hectare per year (LU = one adult cow), old heather cover decreased, young stages increased, and species diversity doubled or quadrupled—including rare species. Coarse and dead vegetation declined, gaps appeared, and lichens and mosses increased from 10% to 50% cover. When grazing pressure dropped, grasses and trees invaded.

At another site, grazing reduced litter height compared to unmanaged areas. Cattle mainly ate grasses in spring and summer (before flowering) and switched to dwarf shrubs in late summer.

Fagúndez (2016) Showed that grazing, mostly by wild ponies in northern Spain, was positively related to plant diversity and vegetation structure. Lack of grazing or high cattle densities resulted in a negative effect on total and rare species richness and diversity.

Groome & Shaw (2015) studied the effects of restoring low-intensity cattle grazing over nine years on post-fire recovery at Folly Bog, Surrey. They looked at four vegetation communities inside and outside grazing exclosures.

Species richness increased in the valley mire, mainly because grazing reduced purple moor-grass and litter, creating more bare ground. This favoured liverworts and water-tolerant grasses. Removing moor-grass and litter also encouraged bog-mosses (Sphagnum spp.), though trampling damaged moss in the wettest areas. On firmer wet heath, trampling was not an issue, and both bog-moss cover and species richness increased due to reduced shade from heather and litter.

The study shows that resuming low-intensity cattle grazing brings many conservation benefits, though other management methods will still be needed.

Piessens et al. (2006) found that heathland vegetation in a Belgian site changed very little during the study period. The proposed management successfully preserved the typical heathland vegetation and its nutrient-poor, acidic character. Their results suggest that extensive grazing, as commonly used in nature reserves, can maintain species diversity even in heathlands affected by high nitrogen deposition and acidification.

Rupprecht et al. (2016) report that year-round grazing by cattle and horses is now common in northwestern Europe, but broad regional studies are rare; especially on nutrient-poor sites where concerns about negative effects on plant diversity remain.

Their study examined five sites in northwestern Germany and the Netherlands, including sand grasslands, dry grasslands, and heathlands. Results showed overall positive effects: plant species richness, endangered species numbers, and open soil increased significantly. Meanwhile, green biomass, litter cover, vegetation height, and woody species decreased. Grazed sites had more small, light-demanding plants, while abandoned sites saw more ruderal species and competitive plants.

They concluded that year-round grazing is an effective tool for restoring and managing open habitats on nutrient-poor sandy soils. However, low biomass and poor forage quality raise concerns about animal welfare and adequate food supply.

WallisDeVries et al. (2016) noted that low stocking rates are often recommended to preserve biodiversity in open landscapes, but detailed guidance on grazing management is still limited; especially for insects, which are more sensitive to grazing than plants. They studied different grazing intensities on insect communities in Dutch heathlands.

They found that early-successional species benefit from grazing, while late-successional species decline. Summer-only grazing was less effective than year-round grazing. Species responses varied with grazing intensity and soil moisture, reflecting their specific habitat needs.

They concluded that low-intensity, year-round cattle grazing or herded sheep grazing can promote insect diversity in large, varied heathlands. In smaller areas, targeted or rotational grazing may be better.

Cox (2005) monitored the effects of reintroducing hardy ponies and cattle grazing at West Bog, Hartland Moor NNR, Dorset, starting in summer 1995. A botanical plot was set up in May 1995, and vegetation height, bare ground, standing water, and photos were recorded every three years (1998, 2001, 2004).

The results were positive: species diversity increased, vegetation height and rank growth of purple moor-grass and straggling heathers decreased, the vegetation became more open, and plants of conservation value, such as sundews, bog asphodel, and bog mosses, became more common. Some reduction in grazing levels was noted between 2001 and 2004.

Lake et al. (2001) concluded in this review is that grazing by livestock is an appropriate management for lowland heathland in terms of delivery of conservation objectives.

Rare plants

Byfield and Pearman (1996) linked declines in rare plant species in heathlands with the cessation of grazing.

Chapman et al. (1989) and Oostermeijer (1994) found that vegetation structure, particularly the amount of bare ground and cover of the litter layer, determine the age structure of the Marsh gentian population which is in turn related to its long term health. Grazing is one method by which such favourable vegetation characteristics can be maintained.

Invertebrates

Thompson et al. (2004) identified changes in grazing regimes i.e. less grazing as one of the main factors responsible for declines of damselfly populations. Grazing is recommended as a key part of good management.

In Dorset there was a large expansion in the range of southern damselfly following the start of a grazing regime on Hartland Moor in 1994.

Heathland birds

Sitters et al. (1996) report that the long-term decline of Woodlarks on Breckland heaths can probably be largely attributed to reduction in grazing, both by stock and rabbits. Grazing is certainly the desirable means of creating and maintaining Woodlark habitat on much heathland.

Sharps et al. (2015) looked at habitat selection by Nightjar within a plantation-forest landscape. Open ungrazed habitat was not selected.

References

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

Buttenschøn, R.M. & Buttenschøn, J. 2015. [in Danish originally]. Long-term effect of cattle grazing on heathland vegetation. Flora and Fauna, 121(3):95-104.

Byfield A. & Pearman D .1996 Dorset's disappearing flora. Changes in the distribution of Dorset's rarer heathland species 1931 to 1993. Plantlife, RSPB.

Cox. J 2005 Botanical monitoring of the Dorset heathlands wildlife enhancement scheme – West Bog, Hartland Moor NNR. Internal English Nature report.

Chapman SB, Rose RJ, and Clarke RT 1989 The behaviour of populations of the marsh gentian (Gentiana pneumonanthe L.): a modelling approach. Journal of Applied Ecology, 26, 1059-1072.

Groome G.M. & Shaw P. 2015. Vegetation response to the reintroduction of cattle grazing on an English lowland valley mire and wet heath. Conservation Evidence, 12, 33-39.

Lake, S., Bullock, J.M., & Hartley, S. 2001. Impacts of livestock grazing on lowland heathland in the UK. English Nature Research Reports, No. 422.

Oostermeijer JGB, Van’t Veer R, Den Nijs JCM 1994. Population structure of the rare, long-lived perennial Gentiana pneumonanthe in relation to vegetation and management in the Netherlands. Journal of Applied Ecology 31, 428-438

Piessens, K., Aerts, N. & Hermy, M. 2006. Long-term (1978-2003) effects of an extensive grazing regime on plant species composition of a heathland reserve. Belg. J. Bot. 139 (1): 49-64.

Rupprecht, D., Gilhaus, K., Hölzel, N., Effects of year-round grazing on the vegetation of nutrient-poor grass- and heathlands—Evidence from a large-scale survey. Agric., Ecosyst. Environ. (2016)

Sitters HP, Fuller RJ, Hoblyn RA, Wright MT, Cowie N &. Bowden CGR 1996. The Woodlark Lullula arborea in Britain: population trends, distribution and habitat occupancy, Bird Study, 43:2, 172-187

Sharps K, Henderson I, Conway G, Armour-Chelu N, Doman PM 2015. Home-range size and habitat use of European nightjars Caprimulgus europeaus nesting in a complex plantation-forest landscape. Ibis 157, 260-272.

Thompson DJ, Rouquette JR, Purse BV (2004) Ecology of the Southern Damselfly, Coenagrion mercuriale. Conserving Nature 2000. Rivers Ecology Series no. 8. English Nature, Peterborough.

WallisDeVries MF, Noordijk J, Colijn EO, Smit JT, Veling K. 2016. Contrasting responses of insect communities to grazing intensity in lowland heathlands. Agriculture, Ecosystems & Environment, In Press,