Inland rock

What is it?

Inland rock, including scree and rocky slopes, is an important component of any mountainside. The sharp ledges and rocky scree slopes support a wide diversity of species. These habitats are often quite limited in extent and can be fragmented. They occur most frequently at high altitude.

Inland rocky areas are split into two groups, calcareous (or lime rich) or siliceous (or acid rich). However, it is not unusual to have a siliceous rock with a calcareous band running through it, which allows plants with different requirements to grow close together in the cracks in the rocks. This variety allows a wide range of plants, bryophytes and lichens to flourish.

The vegetation is often afforded some protection from herbivores due to the inaccessible and unstable nature of the rocky habitat.

A very small percentage of Scotland's land cover

This habitat is difficult to map as it occurs as part of a mosaic of other habitats and can cover very small areas. Geological maps can sometimes help to identify potential areas of interest. There is no exact figure for the area covered by this habitat, although it is likely to be a very small percentage of Scotland's land cover.

Why is inland rock important?

Inland rock is very important as it supports many rare species that demand the conditions provided by the rocky slopes. The enriched soil means that the plants will thrive. However, the diversity and rich vegetation do make these rocky areas very appealing to herbivores, so this fragile habitat can suffer from overgrazing.

Areas of inland rock need a fine balance in terms of grazing, as they can also suffer decline if grazing is too low. This allows the surrounding scrub to encroach onto the rich rocky areas and the more delicate species are 'out-competed'.

Some interesting inland rock species include alpine woodsia (Woodsia ilvensis), green spleenwort (Asplenium viride), Wilson's filmy-fern (Hymenophyllum wilsonii) and tufted saxifrage (Saxifraga caespitosa). Many of these plants have a very limited distribution.

Rocky areas provide important locations for nesting birds. Golden eagles favour inaccessible eyries, where they can safely rear their chicks.

Inland rock habitats provide benefits for people too:

• Recreation - rocky areas are popular with climbers and hill walkers.
• Bird watchers - the rocky slopes and ledges provide nesting sites for many iconic upland birds.