A tiny, terrestrial snail found only on St Helena, the blushing snail (Succinea sanctaehelenae) is the only indigenous snail still surviving on the island. Prior to the 1850s, at least 20 species of snail had been recorded on St Helena; however, the snail fauna of the island was drastically reduced by deforestation, the introduction of non-native species and domesticated animals, pollution and over-collecting (3)(4). Commonly pale amber to golden brown in colour, different populations of the blushing snail vary extensively in their shell shape, size and colour (2)(3). In general, its glossy shell is made up of a small number of whorls which increase rapidly in size, so that while the aperture is very large, the tip (spire) of the shell is short and pointed (2).
The blushing snail is widely distributed around the island, but is particularly abundant throughout the central peaks of St Helena, in habitats which include remnants of native cloud forest, as well as pasture, areas of New Zealand flax (genus Phormium) and forestry plantations. It is also found on the more arid plains of the island, and along stream gorges (3)(5).
Remote islands such as St Helena have unique ecosystems, which are often highly threatened by the introduction of non-native species, over-exploitation of island resources and the destruction of native habitat for agriculture. Since St Helena’s discovery in 1502, most of the native plants and animals have been destroyed and the remaining natural habitat is scattered in small patches across the island (2)(4)(6).
Ongoing threats to native species and their habitats include rapid encroachment by invasive species and increasing erosion (7). Because the entire population of the blushing snail is restricted to this relatively small and isolated island, any further changes to the delicate ecosystem may pose a significant threat to the survival of this species.
A number of organisations, including the St Helena National Trust and the UK Overseas Territories Conservation Forum, are working to conserve the island’s unique environment. By restoring native habitats, managing and removing invasive species, and carrying out research into the flora and fauna of the island, these organisations hope to ensure the conservation of endemic species such as the blushing snail for future generations (6)(7).
ARKive is supported by OTEP, a joint programme of funding from the UK FCO and DFID which provides support to address priority environmental issues in the Overseas Territories, and Defra
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