Hebridensis
Outer Hebrides Wildife
Outer Hebrides Wildife

Flora of the Outer Hebrides

Biodiversity

The flora of the Outer Hebrides had been described by a succession of botanists since the 18th century, however a comprehensive account of the flowering plants and ferns was not published until 1991 (Pankhurst and Mullin). As a result of extensive survey work since 2002 the distribution of the flowering plants and ferns is now comparatively well documented.

The composition and diversity of the vegetation is influenced by the climate, geology, geographical position of the islands and the island effect (the size of the islands and proximity to the mainland). This combination of factors has produced an assemblage of vascular plants that is generally described as relatively small but interesting.
The non-vascular plants (bryophytes, liverworts, freshwater and marine algae) whilst not as comprehensively studied are important elements in the plant biota. A number of Sites of Special Scientific Interest have been designated in recognition of the importance of their bryophyte communities or their populations of aquatic plants and algae.
Flowering Plants

Archaeological studies and pollen analysis indicate that the composition of the flora has changed dramatically through the combination of climate change and man's activities, culminating in an almost treeless landscape. Apart from recent planting, native trees are restricted to islands in lochs, steep-sided gorges and cliffs.
The diversity of the flowering plants of the upland areas and blanket bogs is limited in comparison to the biodiversity of the coastal areas, particularly the machair. These coastal grasslands comprises a complex mosaic of habitat types which support between 100-150 species.

Bryophytes
The mild, oceanic climate is one of the factors which enables an important community of mosses and liverworts to thrive in a variety of habitats throughout the islands. Although conspicuous components of many ecosystems, the species diversity is comparatively low compared with the mainland, primarily because of the restricted range of habitats.
Algae
The varied coastal topography of the archipelago has created a wide range of habitats and consequently the islands are an important area for marine algae (seaweeds). So far over 390 species have been recorded, over 60% of the UK seaweed flora.
There are over 5000 recorded species of freshwater and terrestrial algae (excluding cyanobacteria and diatoms) in the British Isles, however there is currently very little information available on these species in the islands.

In the absence of a website on the flora of the Outer Hebrides this site is the main source of information on-line.

BSBI logo

Launched at the end of 2017 this is the the most recent addition to the hub and is still a work in progress. It covers the seaweeds (marine algae and chromists) and freshwater algae, including desmids and diatoms, and cyanobacteria.

Outer Hebrides Algae website logo