Sharpitor, located on the eastern edge of Dartmoor, is a popular area for visitors to the national park, with easy access and expansive views in all directions. However, what is less well known is its significance as both a geological and ecological upland habitat. Sharpitor is one of the best examples of a collapsed summit tor on the moor, which has enabled a rich plant biodiversity, thus playing an important role in understanding both the natural history of Dartmoor’s granite tors, along with the geological processes that have shaped them. Here we explore why Sharpitor is a classic example of a collapsed tor, and then highlight its unique assemblage of lichens, bryophytes, ferns, and a rare periglacial relict clubmoss.
Understanding Sharpitor’s Geological Importance
To truly appreciate the importance of Sharpitor, it is important to first understand the formation of the granite tor itself. Dartmoor is famous for its dramatic granite outcrops, the result of millions of years of geological processes. Granite, an igneous rock, formed deep beneath the Earth’s surface over 280 million years ago during the Variscan Orogeny. Over time, weathering and erosion have exposed these granite masses, creating the dramatic tors that dot the moorland landscape.
Sharpitor, like many tors on Dartmoor, is a result of the gradual collapse of a once larger granite formation. This collapse occurs through a combination of physical weathering processes, such as freeze-thaw cycles, which cause the granite to fracture, and the erosive action of wind, rain, and ice. As the granite breaks apart, large boulders are left behind, forming the iconic outcrops that we see today. The collapse of the summit tor at Sharpitor serves as a clear example of this natural process in action, making it an essential site for understanding the physical forces that continue to shape Dartmoor.
Lichens, Bryophytes, and Ferns
The unique combination of environmental conditions at Sharpitor — high altitude, exposed rock surfaces, and an array of microhabitats formed from the jumble of boulders and clitter— has led to the evolution of a dynamic environment for a wide variety of lower plants and fungi. One of the most notable groups on the tor are lichens, which thrive in the clean air of Dartmoor, far from the pollution that might affect other regions. Lichens, which are symbiotic organisms made up of fungi and algae, can survive in harsh environments, making them important indicators of environmental quality.
Sharpitor is home to a diverse range of lichens, including species that are specially adapted to survive on the exposed granite. These lichens often grow in patterns that reflect the microhabitats found on the surface of the tor, with some species flourishing in sheltered crevices, while others thrive on more exposed surfaces. Some of the most prominent lichens found at Sharpitor include species of Cladonia (such as cup lichens), Lecanora (rim lichens), and Xanthoria species such as Common Orange Lichen. These species are not only aesthetically striking, with their vivid colours and intricate structures, but they also provide a crucial ecosystem service by supporting biogeochemical cycles through surface weathering and microhabitats for a variety of insect species, which in turn are food for vertebrates such as birds.
Alongside lichens, bryophytes (mosses and liverworts) are abundant on Sharpitor. These so-called lower plants are typically found in humid, sheltered areas, and their presence at Sharpitor adds to the site’s ecological complexity. Mosses, such as the Haircap mosses (Polytrichum) and Woolly Fringe-moss (Racomitrium lanuginosum), are common in the cracks and crevices of the tor’s granite boulders. These bryophytes play a crucial role in stabilizing the substrate and retaining moisture, thus facilitating the establishment of other plant species. Their ability to thrive in the extreme conditions of Dartmoor’s high tops highlights their adaptability and underscores the ecological importance of the site.
Ferns, another lower plant group, also have a significant presence on Sharpitor. Both Tunbridge (Hymenophyllum tunbrigense) and Wilson’s Filmy-fern (Hymenophyllum wilsonii) occur amongst the boulders, often found in shady spots on the tor, benefitting from the cool, moist conditions typical of higher elevations. Both these species of Filmy-fern are largely restricted to western, upland areas of the UK, with Dartmoor being a significant stronghold in the Southwest. Ferns are important for their role in the nutrient cycle, as they contribute organic matter and help to create conditions that support a wide range of other plant and animal life.
A Rare Periglacial Relict Clubmoss
One of the most remarkable features of Sharpitor is the presence of Fir Clubmoss (Huperzia selago), a periglacial relict plant that is a living remnant of the colder climatic conditions that once dominated the region during the last Ice Age. Clubmosses are ancient plants, closely related to ferns, and have been present on Earth for over 300 million years.
Fir clubmoss is a rare species that survives today mostly in upland areas of Britain, with Dartmoor being near the southern limit of its UK range. Its presence on Sharpitor is a reminder of the dramatic climatic shifts that have shaped the Dartmoor upland landscape. Often termed as ‘primitive’ plants, the stems of this tufted, upright fern look like tiny conifers (hence ‘fir clubmoss’), and they reproduce by spores at the base of their leaves.
During the last Ice Age, the area we now know as Dartmoor experienced much colder temperatures, and the flora was more akin to that found in northern Europe. As the climate warmed, many of these cold-adapted plants retreated, but Fir Clubmoss managed to survive in a few refugia, such as the exposed granite tors of Dartmoor, where microclimates remained cooler than the surrounding lowlands. This clubmoss is a true periglacial relict, a living reminder of the region’s ancient past.
The survival of such species in these isolated, high-altitude environments provides valuable insights into the history of Dartmoor’s flora. It highlights the resilience of some species and their ability to persist through periods of climatic change. Sharpitor, with its varied microhabitats and relatively undisturbed conditions, provides an essential refuge for such rare species, making it an important site for conservation.
Ecological Significance and Conservation
Sharpitor’s conservation importance is both geological but ecological. The diverse plant life, including Fir Clubmoss and the thriving assemblages of lichens, mosses, and ferns, makes the site a critical part of Dartmoor’s rocky tor biodiversity. The tor’s exposed granite boulders and unique microclimates create a series of ecological niches that support a wide range of species, many of which are rare or specially adapted to survive in the harsh conditions.
Conserving these habitats is of paramount importance, as climate change and human activity continue to threaten the resilience of habitats such as at Sharpitor. The site’s geological and ecological value is recognized within the Central Dartmoor Landscape Recovery Area, which the DPA is a partner on, ensuring its ongoing management and protection. However, specific monitoring and conservation efforts are needed to safeguard Sharpitor’s diverse flora, especially the rare and specialist species that depend on the granite outcrops. We are embarking on a long-term monitoring programme for Sharpitor’s plant biodiversity to help us manage this important site.
Luke will also be leading guided walks up to Sharpitor to explore its unique ecology during the Dartmoor Outdoor Festival from 29 August – 5 September 2025, so keep a look out for updates over the coming months from our partners at Moorland Guides who are running the event: www.moorlandguides.co.uk/dwf.html You can find out more about the work of the DPA here dartmoorpreservation.co.uk and the wider Central Dartmoor Landscape Recovery Area here www.dartmoorfarmcluster.org/landscape-recovery
By Dr Luke Sutton, Ecologist and Land Manager, Dartmoor Preservation Association
Photos by Helen Bruce