Summary
A description is provided for Eragrostis episcopulus (Poaceae), a previously undetermined grass species from the South Atlantic island of St Helena, together with notes on its ecology, history and conservation. The taxon appears to belong to subgen. Eragrostis, and shows affinities with southern African species including E. minor. E. episcopulus has an estimated world population of just over 2,000 individuals, 90% of which occur in two sites, with the remainder scattered along 15 km of the island’s south coast. All sites are located on the upper parts of cliffs facing prevailing mist-laden winds, between 250 and 550 m altitude. The communities are rich in other rare endemic vascular plants (e.g. Bulbostylis lichtensteiniana, Ceterach haughtonii, Eragrostis saxatilis) and Ramalina lichens. They represent refugial pockets of native diversity amongst degraded scrub, which is now heavily dominated by non-native invaders and thus many locations merit protection. Threats are posed from grazing by rabbits and competition from invasive plant species. As a first step in the long-term conservation of Eragrostis episcopulus, seeds have been collected and an ex situ collection established on St Helena and at the Royal Botanic Gardens, Kew. E. episcopulus is evaluated as critically endangered CR B1ab(ii,iii,iv,v) + B2ab(ii,iii,iv,v) based on the IUCN Red List categories v3.1.
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Acknowledgements
The 2008 Botanical Survey of St Helena was conducted through the South Atlantic Invasive Species Project and funded by the European Union (Project N° 9 PTO REG 5/1 PTR 003/05/EDF IX). Subsequent recording was conducted though the St Helena Field Guides Project (Project N° SH601), funded by the UK Government Overseas Territories Environmental Programme (OTEP). We wish to thank Andre Aptroot for advice on lichen identification. Also, to Rebecca Cairns-Wicks, Eddie Duff, Katrine Herian, Pat Joshua, Lourens Malan and Vanessa Thomas for valuable contributions to both the fieldwork and further discussions associated with this work. Thanks to Maria Vorontsova and another, un-named author for valuable comments on the manuscript.
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Lambdon, P., Darlow, A., Clubbe, C. et al. Eragrostis episcopulus – a newly described grass species endemic to the island of St Helena, its ecology and conservation. Kew Bull 68, 121–131 (2013). https://doi.org/10.1007/s12225-012-9413-1
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DOI: https://doi.org/10.1007/s12225-012-9413-1