FSC | Field Studies Council

Field Studies Council: Bringing Environmental Understanding to All

Shingle Ridge

Slapton sands consists of a shingle bar dividing the freshwater Ley from the sea - it is a dynamic environment, by its nature the shingle is quite unstable  - this results in the shingle ridge being a challenging environment for plants to establish.  Walking along the seaward side of the ridge you will be unlikely to come across any signs of vegetation until you reach the upper parts of the beach near the strand line, here plants can start to take hold - perhaps using nutrients from deposited seaweed as a starting point a few pioneer species can establish.  Any closer to the sea and the area is too frequently disturbed and lacking in resources to allow any plants to grow.

Pioneer species have amazing adaptations to allow them to survive in the harsh conditions of living on the ridge, many of these aim to collect and preserve water within the plant.  The Yellow-horned Poppy and Sea Kale have thick, waxy leaves to prevent water loss and a bluish white tinge to reflect sunlight and help prevent sun burn!  Plants that can tolerate these dry conditions are called xerophytes.  Rest Harrow forms a mat to stabilize the shingle and also has a symbiotic, mutually beneficial, relationship with bacteria that make nitrogen, an essential for plant growth.

yellowhornedpoppy2.jpg
restharrow2_002.jpg
Yellow-horned Poppy
Rest Harrow

As you travel inland the shingle becomes less regularly disturbed by the sea and a thin layer of soil starts to appear as more and more plants are able to grow and add nutrients and organic matter.  Plants appearing at this stage have to cope with low nutrient levels, they are sometimes called maritime specialists and most can tolerate high levels of salt - halophytes.  The lack of available nutrients means that some plants in this area grow relatively slowly.  Sea Carrot is a biennial plant spending the first year germinating and growing without flowering or producing fruit.

The process by which plants change the environment through their presence and enable other plants to tolerate the conditions here is called facilitation.  This is an important part of succession, which is the gradual change in the vegetation present in an area over time.

vetch.jpg
seacarrot2.jpg
Common Vetch
Sea Carrot

 

It is easy to see succession happening along the profile of the ridge from sea to Ley with noticeable increases in plant number, diversity and size.  Along the back slope next to the Ley the meadow and scrub communities compete for space, with some plant species growing much taller or even climbing up other plants (vetch) to reach light and attract pollinators.  Eventually the vegetation community will reach a stage called the climatic climax, where a particular species will dominate depending on the climate of the area; here we would expect to see deciduous woodland.

ridgeprofile.jpg
Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession

There are some interruptions to the succession pattern here though, one significant break in the ridge is the road which does help to stabilise the area but may prevent certain species migrating across.  Other areas have been trampled to form pathways or managed in some way to bring them back to an earlier stage of succession.