Over the past 150 years up to 85% of lowland heathland has been given over to agricultural use and conifer planting. Heathland soils can become enriched by agriculture affecting their suitability for heathers. Pressure from developers, keen to use heathland for building is a further threat.
Much upland heath has been over grazed, while lowland heath is sometimes drained, threatening the wildlife that lives there. Meanwhile, heathland that has not been managed has gradually become woodland.
Airborne pollutants such as nitrogen and ammonia also pose a threat to the vegetation of heathlands, particularly mosses and lichens. As heathlands are naturally low in nutrients, they are extra susceptible to harm caused by excessive atmospheric pollution. In the UK, nearly 30% of dwarf shrub heaths and 97% of montane habitats were found to exceed their critical loads for nitrogen in a 2006-2008 study.
Heathland is also at risk of fire as the types of plants that grow there are highly flammable. A misplaced barbecue or discarded cigarette end can have devastating effects on large areas of heathland. Some fires are also started deliberately. In 2020, a fire in Wareham Forest in Dorset affected approx 220 hectares of heath and woodland, and needed help from 50 fire stations to bring it under control in a rescue operation lasting two weeks. A fire on Upton Heath in 2011 damaged around 250 acres heathland and took 30 fire engines and 11 Land Rovers to put out the blaze.