Ascension Island: Hooker’s lost parsley fern found on mountain

17.08.10 by Stedson Stroud and Olivia Renshaw

On 27 July 2009, the Ascension Island Government’s Conservation Team were conducting a routine annual plant census with botanist Dr. Phil Lambdon. “We were exploring a narrow ridge on the southern side of Green Mountain. By chance, Phil and I noticed a tiny frond sticking out of a crevice in the rock." Stedson Stroud and Olivia Renshaw tell the story of their chance discovery.

Phil Lambdon taking photos of the rare parsely fern

Dr. Phil Lambdon, botanist with the UK Overseas Territories Programme at Kew, photographs

the first Anogramma ascensionis to be seen in more than 50 years. © Stedson Stroud

Most of the vegetation on Ascension Island has been introduced by humans. Some species spread dramatically and now occur throughout the Island, but goats released onto Ascension by Portuguese explorers in the 1500s ate their way unchecked through the vegetation for 350 years before the flora had been identified and recorded. Further introductions of rabbits, sheep, rats, donkeys, and over 200 species of invasive plants, drastically reduced the habitat range of the natural vegetation and until last year there were only six surviving endemic plant species on the Island.

Botanist Joseph Hooker visited Ascension in 1843 and found many parsley ferns on Green Mountain, which he named Anogramma ascensionis. The ferns were recorded several times in the 19th century and last recorded by Duffey in 1958. In 2003 the species was officially declared extinct on the IUCN Red List.

That was until the exciting discovery on the narrow ridge of Green Mountain. The team instantly recognised it as the ‘extinct’ parsley fern and busily searched for more on the steep slopes. Another four were found in quick succession.

small green fern which has been rediscovered on Ascension

The tiny parsley fern (Anogramma ascensionis) was declared extinct in 2003 by IUCN,

but the exciting discovery of four plants in 2009 on a remote mountain ridge has given

conservationists hope for its future. © Reinhard Mischke

Stedson and Olivia hanging from a rock looking for the rare fern plantsOver the next two months my colleague, Olivia Renshaw, and I returned to the ridge to water the ferns and clear weeds from the crevices (pictured left). The waiting was nerve-racking. We weren’t sure how long it would take for the plants to produce spores, we just had to be patient and check them every week. it was very important the spores were collected before they were shed. Due to this care and attention two of the plants survived long enough to produce spores.

The Royal Botanic Gardens, Kew had agreed to help save the future of these precious plants. Viswambharan Sarasan and his colleagues in the Conservation Biotechnology Unit (CBU) offered their expertise as they have experience in growing endangered ferns in culture.

When I judged the spores to have formed, the Island’s Administrator, Ross Denny, and I went to clip tiny pieces of frond from two ferns. It was a very delicate operation. Taking fronds from such delicate plants growing in such harsh, dry conditions was a real worry. The fronds were placed in a sterile, sealed container to protect the spores from contamination and drying. It was a race against time: we had just 24 hours to transfer the spores to Kew. They were flown to RAF Brize Norton via the Airbridge, where Marcella Corcoran of Kew’s UK Overseas Territories team was waitin and as soon as the spores arrived at Kew Viswambharan Sarasan and Katie Baker set to work on them.

Kew now have a number of plants growing in vitro and the aim is to store the sporelings safely in the tissue bank, conserved using a method called cryopreservation in liquid nitrogen. Back on Ascension I also managed to successfully germinate spores and we now have eight sporophytes growing in our endemic plant nursery on Green Mountain. But the plants seem to fighting their own battle too as since the initial discovery further searches of the site have revealed more parsley ferns clinging to life.

two men hunting for plants on rocky mountain top

Ross Denny and Stedson Stroud taking clippings from the tiny ferns. © Reinhard Mischke

Rediscovering endemic plants that that have been officially declared extinct and bringing critical endangered plants back from the brink of extinction is truly a magnificent accomplishment for me.  

Ascension Island is a UK Overseas Territories and is one of the most isolated islands in the world. It is a dormant volcanic island in the South Atlantic Ocean, 1700km off the coast of Africa. Ascension’s landscape is dominated by Green Mountain (859 m, 2818 ft), the island's peak and a National Park.

Related links:

Ascension Conservation

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