Acid grassland and biodiversity on Friary Hills

What is acid grassland? 

Acid grassland has undergone substantial decline in the 20th century and is locally scarce. As the name suggests, it is a type of grassland habitat that it is characterised by acidic soil. It can be home to a diverse array of plant species - the best examples can contain as many as 25 plant species per square metre.   

Characteristic plant species include fine grasses, lichens and mosses, as well as small rosette-forming species such as cat’s-ear and mouse-ear hawkweed, low-growing herbs such as sheep’s sorrel and bird’s-foot-trefoil, and tiny annuals such as common stork’s-bill, changing forget-me-not, and parsley piert.  

Many of the invertebrates that occur in acid grassland are specialist species which do not occur in other types of grassland.  

Acid grassland on Friary Hills 

Friary Hills lies to the east of Blakeney village, between the precinct wall of the ruined Carmelite Friary and Blakeney Freshes grazing marshes.  

There is a mosaic of scrub and acid grassland on its steep north facing slopes. This mosaic supports a diverse range of plants, invertebrates, and bird species; it is important for migratory birds flying in from the continent that use the scrub to stop and rest. 

A more active approach to maintaining the acid grassland on Friary Hills is needed for a combination of reasons:  

• scrub and tree cover has increased over the last 20 years and is encroaching on acid grassland habitat;  

• there is a significant presence of non-native species (linked to the former use of the site as a caravan park) which can compete with native flora and fauna;  

• and reduced rabbit grazing pressure has led to the acid grassland sward becoming rank in places with potential loss of species diversity.

How a mosaic of habitats supports biodiversity 

Work is underway to increase the amount of acid grassland on Friary Hills and to enhance its condition - whilst maintaining the principle of a mosaic of habitats.  

Biodiversity tends to be particularly rich at the margins of habitats, which is why a mosaic of scrub and acid grassland is more desirable than simply removing all the scrub and allowing acid grassland to take its place.    

The role of cutting and grazing 

Our rangers will be working to optimise the grassland structure and species composition through annual mowing and cutting.  

Acid sward needs to be short (2-10cm in October/November) with fine leaved grasses and forbs (herbaceous flowering plants that are not grass, sedge, or rush) such as harebell, stork's-bills, medicks, trefoils and sheep's sorrel.  

Eventually, the aim is that sheep or goats will be brought on to Friary Hills to help this process through grazing. 

Reducing scrub and non-native trees  

To increase the acid grassland area on Friary Hills, we will be cutting back on some of the scrub and reducing some of the non-native trees such as sycamore, black pine, turkey oak and beech.  

Visitors may notice our rangers cutting back areas of gorse or removing the odd non-native tree. This work will not dramatically alter the overall appearance of Friary Hills and important amenity trees will be retained. This work will be timed to avoid bird breeding season.  

A gradual transformation of Friary Hills 

The long-term nature of the project means that most visitors will notice very little change from one visit to the next. The real changes will be seen in the longer-term.  

Over the next 5-10 years, our land management plan for Friary Hills will progressively bring its acid grassland to full and vibrant health - with a diversity of wildflowers, lichens and mosses, buzzing with invertebrates, attracting migratory birds, with the sward managed through a combination of grazing and annual cutting.  

It’s an exciting project which promises to rejuvenate an important habitat for Blakeney residents and visitors to enjoy for generations to come.