Rare Moss Numbers Triple at site in One Afternoon

In 2003 Aspen Bristle-moss, which was thought to be extinct in the UK, was rediscovered by a chance finding. Now, thanks to a team effort – moss experts, landowners and volunteers discovered 3 times the amount of Aspen Bristle-moss at one site. This brilliant find led to the known population of this rare moss doubling in Scotland in a single afternoon.

This amazing feat was thanks to a training session organised by our Resilience and Recovery, Helping Rare Species Adapt to a Changing World Project Manager, Sam Jones, where volunteers were taught how to ID this marvellous moss. 

The elusive epiphyte (a plant which grows on the surface of another plant) is particularly tricky to identify, with tiny features that distinguish it from the other mosses that can be found growing alongside it. 

This event, helping uncover hidden populations of Aspen Bristle-moss gives hope for it’s future.  

Read on below as Sam explains more about the day and this special species. 

Learning How to ID the Rare Aspen Bristle-moss

On 6 November last year, we had our first day looking at Aspen Bristle-moss in Deeside. A total of 12 of us — moss experts, local land managers, and keen volunteers — spent around 4 hours staring very closes through hand lenses at Aspen bark.

Our experts taught us exactly which tiny features to use to distinguish these mosses from all the others we might see on Aspen bark. We learned about the importance of wetting the mosses before trying to identify them.

Then we walked all over the site which is a very rare dense exclusively Aspen woodland covering around 5 hectares. About 20 of these trees were known to support Aspen Bristle Moss, nearly half of the total known UK population. On our sweep we increased the population on site to 49, nearly doubling the total known population in 1 afternoon alone.

How are we Protecting this Rare Moss?

It seemed a logical choice to focus on such an understudied local specialist species. While working to protect this moss, we are also hunting for and protecting other rare Aspen epiphytes, such as Blunt-leaved Bristle-moss Nyholmiella obtusifolia, Showy Bristle-moss Lewinskya speciosa, and Bark Sulphur Fire-dot Lichen Caloplaca flavorubescens.

We are early in our journey towards protecting these species. Alongside preserving and enhancing Aspen woodland, work led by the Cairngorms National Park and Trees for Life, we are focused on learning the status of these species, and what we can do to protect them.

The first step for Aspen Bristle-moss (and all these under-studied epiphytes) is to update our records.

In 2000 it was thought to be extinct in the UK but has since been rediscovered at 3 sites. It takes quite the specialism to record it, and so there is a good chance some populations remain undiscovered. So, our first objective is to re-survey the 3 known populations, and to get people out and looking for it across Aspen woods more widely.

What’s Next for Aspen Bristle-moss?

This year we’ll be surveying the other 2 populations, getting more people trained up to look for and appreciate these rare species, and developing a better idea for how it is doing. We’ll also be encouraging trained volunteers to check Aspen trees whenever they can, as it is very possible many sites remain undiscovered.

As our understanding of these species expands, we may start to look at what can be done to protect these tiny remnant populations. Obviously, we must continue to promote and protect Aspen woodlands. We also may look into transplanting mosses between trees or assisting their colonisation into new sites.

We will have to see what develops as we work to protect and promote these often-overlooked tiny green gems.