Killarney National Park, “world-renowned and internationally significant for the number of bryophytes that occur there”, is still capable of revealing secrets, according to the National Parks and Wildlife Service (NPWS).

Two years after a new species to Europe was first discovered there, a second population of the Kerry Mousetail Fern has just been found.

In September of this year, it was found in a very remote woodland in the uplands of the park, over 4km distant from the previously known location, the NPWS said.

“Six plants were found to be present on a vertical rockface above a stream, one of which was fully mature and producing spores.

“This discovery proves that this species is fully established in the Killarney National Park, and is not merely a transient colonist that will quickly disappear again.”

Species likely arrived ‘without human intervention’

The fern was first discovered in the park back in July of 2019, as a new species in Europe.

“This species was previously found only in the Caribbean, in the tropical cloud forests of Jamaica, Cuba and the Dominican Republic, and is a member of a group of tropical ferns known as the Grammitid Ferns,” the NPWS explained.

“No members had been previously found in Europe, aside from in Macaronesia, a collection of four volcanic archipelagos in the North Atlantic Ocean, off the coasts of the continents of Africa and Europe.”

The NPWS said it believes that this species arrived in Ireland “without human intervention”, with the most likely explanation being that “its tiny spores travelled across the Atlantic on the wind and happened to land in a place where conditions were suitable for it to grow”.

“It is not clear how long this species has been present in Ireland and only 40 plants were found on two rocks in one location, making it an extremely vulnerable and threatened plant,” a spokesperson said this week.

Possibly ‘survived undetected for number of years’

The NPWS has embarked on a suite of taxonomic and botanical surveys in Killarney National Park over the last two years, with a particular focus on niche specialists.

It is not known when the rare plant first established itself in Killarney National Park.

The NPWS is looking into the suggestion that it has “survived undetected in the area for at least a number of years, and may not be a recent arrival, having possibly been present for decades, centuries or even longer”.

“Due to its very small size and tendency to grow in remote areas, it would be very easily overlooked by generations of botanists,” the NPWS said.

“However, the fact that it has now been found in two disparate areas means that it is very likely that the Kerry Mousetail Fern occurs elsewhere in the park, or further afield, as many pockets of similar habitat exist where conditions are suitable for its growth.

“This discovery puts to rest any doubts that may have existed about whether this enigmatic neotropical fern can be considered a full, established member of the Irish flora.”