Island’s large bellflower ‘could be lost’ to genetic mix-up

St Helena’s endemic large bellflower could become extinct within a few years – even though it is raising new plants.

The fear for conservationists is that the few remaining wild plants are getting mixed up with another endemic species, the small bellflower – and soon their may be no true specimens left.

A conservation programme is on hold because it’s not even clear which plants can safely be used for raising seedlings.

On top of that, landslips threaten to sweep away the few surviving wild plants.

Phil Lambdon of St Helena National Trust said: “It is currently our most threatened flowering plant, with a few wild plants scattered between High Peak and the Depot only.

“Aside from being very rare, all of the sites are on unstable cliffs prone to landslips, and the species is hybridising extensively with the small bellflower, so we are in real danger of losing it completely through genetic contamination.

“This could leave a mix of plants with an ‘in between’ appearance, and no true individuals left.

“And it could happen within a few years.”

Fuschia and New Zealand flax are seen as the main causes for decline in the plant’s fragile habitat.

A genetic study is under way, funded by the Mohamed bin Zayed Species Conservation Fund, to try and work out which of the remaining small, shrubby plants are pure.

The charity put up £9,000 for the work in December 2012.

“Until we have done this we can’t really assess true numbers, or mount a proper conservation plan,” said Phil.

“The cultivation programme is partially on hold too, as it may not be safe to breed unless we know that the parents we pollinate from are guaranteed to be pure.”

The nursery at Scotland has conducted trial cultivations over a number of years.

Phil said: “There are about seven or eight individuals in cultivation at present, and there are 50 in the wild which might be pure – mostly very small and ailing, but still hanging on.”

The global “red list” of threatened species says they face “an extremely high risk of extinction in the wild in the immediate future.”

St Helena once had four types of bellflower, but two are now lost. The large bellflower was common in the 19th Century, often growing out of the tree fern trunks in the cloud forest.

The website for the bin Zayed foundation says: “The reasons for the alarming decline in the large bellflower are unclear, but a sharp decline in the area of mature tree fern thicket and forest in the early 20th Century is likely to have been the major factor.”

The plant was listed as critically endangered in 2003, “and since then its status has deteriorated further.”

The project aims to prevent immediate extinction by weeding out invasive species and taller native plants, working out which plants are pure, working out how to prevent cross-pollination, and establishing a population of pure individuals in the conservation nursery. 

Leaf samples have been sent to Canada for analysis by Professor Quentin Cronk – one of the men who rescued the St Helena ebony plant in the 1980s.

If conservation efforts succeed, pure specimens could be reintroduced on high ground across the island.

LINK: Mohamed bin Zayed Species Conservation Fund – large bellflower project

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0 Responses to Island’s large bellflower ‘could be lost’ to genetic mix-up

  1. Stephen Meyers says:

    Given that large-bellflower so readily hybridizes with another island endemic (small-bellflower), this may indicate that the taxonomy of this species is incorrect (this is more common in botany than one might imagine). In other words, large- and small-bellfower may be parts the same species. The differences between the two species may be merely be morphological plasticity within one species (some plants within one species simply having larger or smaller flowers than others…much like some humans are short and some are tall). If this is the case, the large-bellflower species may not actually exist (in a biological or practical sense) and the numerically larger, unified bellflower species may not actually be rare (unless small-bellfower is also very rare).

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