Discover Shetland's Biodiversity
by Howard Towell -
Shetland, it's for the birds.
The one thing that every visitor to Shetland can't fail to notice is the teeming bird life, there are birds everywhere! Over one million birds of 70 different species breed in the islands. Many of these are of national and international significance. As well as breeding birds, Shetland is of great importance to migrating birds with over 430 species recorded in the islands. With such a huge number of individuals either breeding or passing through the islands, and a human population of only 20,000, it could be argued that Shetland is for the birds.
Add an abundance of marine life, sea mammals such as grey and common seals, regular sightings of whales, dolphins and porpoises, one of the highest densities of otters in the UK and an interesting and diverse flora, it is little wonder that Shetland has attracted naturalists and ornithologists for centuries.
The main reason for Shetland's abundance of wildlife is its geographic location. Situated midway between the UK and the Arctic, Shetland is on a migration flyway. Large numbers of birds pass through the islands on their migrations to and from the Arctic. Several species stop off to feed, and the island's position also attracts many vagrant species from North America and Asia that have been blown off course. As a result Shetland is renowned as a rarity hotspot which also incurs a human migration, that of birdwatchers who visit the islands every spring and autumn in the hope of finding some of these rare stragglers.
Shetland is situated close to the edge of the European continental shelf, where nutrient rich waters from the deep Atlantic mix with those of the shallower North Sea creating ideal conditions for the production of phytoplankton, which feeds a higher food chain of zooplankton, fish, seals, cetaceans and seabirds. The proximity of Shetland to these rich feeding grounds provides convenient and relatively undisturbed breeding sites for the 23 species of seabird and two species of seal that breed here.
Shetland's relatively wet oceanic climate has helped to create a large expanse of blanket bog in the interior of the islands, which is attractive to many species of moorland breeding birds particularly wading birds such as Curlew, Whimbrel, Dunlin and Golden Plover.
Shetland contains a varied and interesting plant life. The vegetation is largely blanket bog dominated by heather, cotton grass, dwarf shrubs such as crowberry and bilberry and sphagnum moss. On first impressions this appears somewhat bleak but a closer look reveals a range of hues; purples, reds, ochres and greens made up of heather, grasses and sedges, mosses, liverworts, ferns and lichens. The numerous freshwater lochs, pools and marshes also contain a variety of aquatic plants. The lower lying land consists of pasture, grasslands and coastal heath. Many of these grasslands have had no or very little agricultural improvement and consist of a mixture of grasses, plantains, mosses and many species of wild flower that provide a colourful display throughout the summer. Plants such as Thrift, Spring Squill, Heath-spotted Orchid and Autumn Hawkbit can bloom in their thousands creating an impressive and memorable sight.
Unique to Shetland
Some flowering plants are unique to Shetland and found nowhere else in the world. Edmondston's Chickweed is confined to two sites on serpentine outcrops on the island of Unst. There are 17 species of hawkweed that are also exclusive to Shetland but you will need expert knowledge to tell them apart. Whilst these plants are distinct species, Shetland also has a few subspecies, such as the Shetland and Fair Isle Wren, superficially similar to Wrens on Mainland Scotland but with subtle differences in size and colour characteristics. These distinct species and subspecies have evolved over a long period of time and are as a result of Shetland having been isolated from Britain and Europe for over 10,000 years.
Because of the island's isolation there are no native land mammals, reptiles or amphibians in Shetland. All the land animals were introduced by humans at some time in the past, even Otters were probably introduced by the Vikings for their pelts. Other introduced mammals include mice, rats, Hedgehogs, Rabbits, Polecat-Ferret, Stoats and Mountain Hares. The latter were brought to the isles as a sporting animal from mainland Scotland in 1907, no longer hunted these animals have found Shetland moorlands to their liking and can be seen in most hill areas in mainland Shetland although the best time to see them is in winter when their coats turn white making them stand out against the dark moorland vegetation.
Posted in: Exploring Shetland