Today’s blog is by RSPB Ellie Dimambro-Denson, Monitoring Officer and Pip Gullett, Conservation Scientist – both working with the Cairngorms Connect project.

Twinflower (Linnaea borealis) is a small delicate flower, native to pinewoods in Scotland. Interestingly, the first half of twinflower’s scientific name, Linnaea, comes from Carl Linnaeus, the ‘father of modern taxonomy’ who created the system for naming organisms binomially, whose favourite flower was twinflower.

If you’re lucky enough to catch a glimpse of one of these beauties in flower, you’ll understand why! It can be found growing around the northern hemisphere in what’s known as the boreal forest zone (indicated by the second half of its scientific name – borealis), ranging from northern Europe to Siberia, Alaska, Canada and Greenland, as well as some mountainous areas at lower latitudes.

Once widespread in the ancient Caledonian forests of the Scottish Highlands, centuries of deforestation and conversion of natural forests to managed plantations has greatly restricted its distribution within Scotland to small isolated patches, to such an extent that it is now classed as nationally scarce.

Pollinator visiting a twinflower patch (© Cairngorms Connect)

A flower on the brink

In the few places where they still persist, twinflower can form quite large, apparently healthy patches. But don’t be fooled! As twinflower can spread through vegetative propagation, even quite large patches might be made up of just a single genetic individual (aka ‘clone’). In fact, in Scotland a huge 80% or so of twinflower patches comprise only a single clone, with most of the remaining 20% of patches containing just a handful of very closely related individuals.

This puts populations at risk of extinction – if patches were to become subject to disease or environmental change, all individuals would be equally susceptible, as opposed to potentially including advantageous variations of genes that could promote survival. To increase their genetic diversity, and ultimately persist into the future, twinflower needs to be able to reproduce sexually with a different clone.

However, there’s another of the problems – most of the remaining neighbouring patches are too far apart for the small flies that pollinate them to travel between patches, meaning that there is very limited cross-pollination and therefore seed production. As a result, intervention is needed to help ensure twinflower’s survival within the Scottish landscape.

Collecting twinflower from a donor patch. Stolons collected were up to 40cm long with at least one set of well-developed roots, ideally with several branches © Cairngorms Connect

In 2014, as part of the Cairngorms Rare Plant Project, a series of translocations led by Andy Scobie were set up to bring together several isolated clones together at a single site, close enough for pollinators to travel between them. Two different methods were used to do this: establishing new populations (i.e. introducing multiple patches of twinflower from several different clones to the same site within areas of suitable habitat) and augmenting existing populations (i.e. planting additional clones within pollinating distance of existing healthy single-clone patches).

Autumn work

Building on from this work, in autumn 2019, Cairngorms Connect revisited some of the patches previously augmented with additional genetic individuals to add more to each site so that each natural patch was surrounded by 8 genetically unique individuals, close enough for pollinators to travel between.

This autumn, we decided to focus on reintroductions to new areas of suitable habitat within the Cairngorms Connect partnership area. We identified ten new sites within RSPB Abernethy and Forestry and Land Scotland’s Glenmore with favourable conditions for twinflower both now and in the future, as restoration work continues within the forest to expand this habitat.

Twenty genetically distinct, healthy twinflower patches within the Strathspey area with similar ecological characteristics to the release sites were also identified and stolons (i.e. the creeping stems that form patches of twinflower) with plenty of roots were collected from each to be planted at the release sites. At each release site, six clones were planted in clusters of 16 stolons, with each cluster located within 10m of its neighbour to help pollinators to travel between the clones. Throughout October, 960 individual stolons of twinflower were translocated and planted within the Cairngorms Connect area.

Left: A translocated twinflower stolon in its new home. Right: Planting a recipient plot with twinflower. (Both © Cairngorms Connect)

Twinflower in 2021

And so, what’s next for twinflower in the Cairngorms Connect area? In 2021, we’ll be revisiting the sites set up in 2019 to take a full baseline survey of how the new twinflower stolons have been settling into their new home and re-visiting the sites from this year to do the same in 2022. With other organisations including Plantlife Scotland and National Trust for Scotland also looking to carry out additional translocation work in the National Park, it’s a hopeful time for twinflower conservation.

All going well, these new populations will form a bridge to increase twinflower genetic diversity in the Cairngorms, that will dramatically enhance the resilience of remnant populations as well as enabling them to spread and disperse, thereby ensuring the survival of the species within Scotland into the future.

Cairngorms Connect is a partnership between RSPB Scotland, Forestry and Land Scotland, NatureScot and Wildland Limited, working towards a shared 200-year vision to enhance habitats, species and ecological processes over a connected landscape. They are assisted with funding from the Endangered Landscapes Programme. A huge thank you to Andy Scobie for his help and expertise through the project, to neighbouring land managers, including Seafield Estate, for donations of twinflower material, as well as Richard Ennos and all the volunteers who helped with the translocations on the ground.

For more information, please contact Ellie.Dimambro-Denson@cairngormsconnect.org.uk or Pip.Gullett@cairngormsconnect.org.uk

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