Shetland Amenity Trust is helping to conserve an endangered species of hawkweed, Hieracium hethlandiae, which is now extinct in the wild.
Shetland is host to some 26 species of hawkweed plant, 18 of which are endemic to Shetland. They are all considered to be in decline, largely because of overgrazing by sheep, although Hieracium hethlandiae was removed by quarrying at Mavis Grind. The surviving species tend to be confined to locations relatively inaccessible to sheep.
One of the successes to date is that the Hieracium hethlandiae, which was extinct in the wild, is nevertheless still growing in artificial cultivation and will be reintroduced into the wild in due course.
Shetland Amenity Trust’s woodlands team and Shetland Biological Records Centre are partaking in a national species action plan for Shetland’s endemic hawkweeds, in partnership with Scottish Natural Heritage (SNH) and Shetland Conservation Volunteers.
Shetland botanist Walter Scott has also contributed to the success of the project by way of advice and material.
The woodlands team is sowing seeds of each species, with the aim of maintaining 50 pots of each. Once this goal is attained, seed is collected from pots after flowering, and sown as “plugs” in trays; these are then transplanted “into the wild” by the conservation volunteers, under the supervision of SNH. Any surplus seed is kept refrigerated in seed banks for future use.
The key objectives of the project are to ensure that there are at least two viable populations of each species in Shetland, and to maintain an ex-situ collection of them in cultivation.
Hawkweed species may look very much alike, but there are significant differences in flower and leaf structure. Hawkweeds are apomictic, that is to say they reproduce without fertilisation, and each species comprises a distinct clone.
In cultivation, it is essential to make sure that seeds from one species do not get transferred into the pots of another, so that the populations remain “pure”. This requires very careful manipulation of the collection, so that flowering and seeding species are kept isolated from each other.
Tim Rich, head of vascular plants at the National Museum of Wales, was in Shetland recently on a research trip to examine hawkweeds. Dr Rich is a hawkweed specialist who, with local botanist Mr Scott, is shortly to publish a book on Shetland hawkweeds.
He said: “I was very impressed by the scale of the work growing the hawkweeds, and the understanding of their importance and how to grow them. This is the best example of cultivation of these plants for conservation I have seen. The work the trust are undertaking in maintaining populations in cultivation is of clear importance.”