Combining genetics and ecology to save species from extinction.

Dr Aline Finger is a conservation geneticist at the Royal Botanic Garden Edinburgh (RBGE). Her work focuses on generating evidence-based management strategies for species facing extinction in the UK. Using a combination of genetic and ecological methods she guides protection of threatened plants to ensure that conservation efforts lead to species’ persistence as self-sustaining, viable populations.

Combining science, horticulture, and applied conservation

Aline’s work enables plants to persist in the wild, and maximises their potential to adapt to changing environments, by maintaining genetic health through sustaining multiple, large, connected populations.

For many rare species, the first step is to determine a plant’s current status, in terms of the number of distinct genetic individuals, level of genetic diversity, and rates of reproduction within populations. Then, the potential benefits for long-term survival of increasing genetic diversity and connectivity are tested through cross-pollination experiments which enhance opportunities for gene-flow between populations.

Many of the species Aline works with are grown in cultivation in RBGE’s nursery, where with dedicated horticultural staff she maintains quality ex-situ collections with detailed records of parentage, providing high quality plant material for translocations. In tandem, ecological experiments in the nursery and trial translocations in the wild help characterise species’ ecological requirements.

This combination of ex situ and in situ research underpins, where appropriate, science-based translocations of material back into the wild, to supplement existing populations or reintroduce species to new suitable sites. All reintroductions are subject to strict quarantine and testing to minimise the spread of pests and pathogens.

This is dedicated, long-term work: “Persistence is key…” Aline emphasises, “Populations are monitored over many years, which is crucial to obtain meaningful data, support continued habitat management and ensure a long-term legacy.” Collaboration is also crucial: “We work with government, conservation agencies and land managers to ensure that scientific findings feed directly into ex situ conservation actions, in situ management plans, and proactive reintroductions,” she says.

A journey to recovery for a threatened Scottish plant

The deadly combination of habitat loss and fragmentation with climate change is widely considered the primary threat to terrestrial biodiversity today. Globally, two in five plant species are already threatened with extinction. “In Scotland alone, around 200 species are currently of conservation concern,” Aline explains. “A lot of these species are scattered in the Scottish landscape as small populations, isolated from each other by unsuitable habitat, with limited opportunities to expand naturally.” One of these species is the alpine-blue sowthistle (Cicerbita alpina), and it is also one of Aline’s success stories.

Nationally Rare and Vulnerable in the UK, the alpine-blue sowthistle is amongst the largest and rarest of Scotland’s boreo-montane plants, and has been grown for conservation at RBGE since 1999. Closely related to the garden lettuce, this tasty species has been decimated by grazing sheep and deer and is now, along with other members of the tall herb community, restricted to a few steep ledges and gullies inaccessible to grazing animals. By 2017, fewer than 100 of these striking, 1.5m tall, blue-flowered plants remained in the whole of the UK, all in Scotland: at four isolated sites in the Cairngorms National Park. “Our research highlighted that these remaining populations have a low genetic diversity, high levels of inbreeding and fail to expand from their tiny ledges,” Aline explains.

A human touch

In cases like this, only human intervention can now prevent extinction. And often habitat conservation alone is not sufficient to prevent continuing decline: there is an increasing need for conservation translocations, the intentional movement of species for conservation purposes, as a measure of last resort. Working with NatureScot and land managers, Aline and her team worked to restore the genetic health of the sowthistle populations through cross-pollinations to maximise genetic diversity, growing up large numbers of genetically diverse plants, and conducting trial translocations to understand their growing requirements.

Between 2017 and 2021, using evidence gathered over several years, they planted over 1,200 nursery-grown plants at 12 carefully chosen, suitable sites in Scotland. “The first monitoring results indicate that genetically crossed plants are doing particularly well at the translocation sites,” Aline says modestly.

Aline studied biogeography in Germany and, convinced that she would work on animals, did her MSc thesis on the conservation genetics of a threatened butterfly species. She then found, she says, “Her absolute dream PhD position – which turned out to be on conservation genetics of threatened and endemic tropical trees.” Having shifted path to focus on plants, she came to RBGE for a one-year project and has been working on Scottish plants there ever since.

Three people walking up a steep grassy slope in the Highlands, with a small loch in the valley below. Aline is in the front, in a yellow jacket with a backpack on
Dr Aline Finger, leading an expedition in the Cairngorms National Park

This combination of focused genetic research, conservation horticulture and targeted land management has made the alpine-blue sowthistle a flagship for threatened species recovery and an excellent case study showing the amount of work required to bring threatened species back from the brink of extinction.

Everything you need for successful conservation

“There is not much that can beat the views and the feeling of sitting on top of a hill in the Scottish Highlands after a long field day,” Aline enthuses. “Scotland is a beautiful country to work in, hosts excellent research institutes and many conservation organisations. Consequently, there are many fantastic projects underway to help nature recover, including conservation translocations, rewilding projects, and habitat protection programmes.” She particularly values the close collaboration between conservation bodies, research institutes and landowners, crediting the success of the alpine-blue sowthistle project to strong working relationships with NatureScot and landowners such as the National Trust for Scotland, Glenfeshie and Glenlochay Estates. “They allow us to use their land and help us looking after the plants, setting up cameras to document grazing activities, and monitoring the plant populations. It’s these collaborations, working to achieve one goal, that turn seemingly small projects like the translocation of a single species into big success stories,” she concludes.

Dr Aline Finger is a molecular ecologist at the Royal Botanic Garden Edinburgh. Her work is supported by the Scottish Government Rural and Environment Science and Analytical Services Division, NatureScot, the players of the People’s Postcode Lottery and the Magdalene Sharpe Erskine Trust. Her work has been recognised with a Holyrood Green Giant Award for Nature and the Environment, and a Nature of Scotland Award for Innovation. Find out more here.

This post is part of a series showcasing Scotland’s innovative, high-impact research supporting biodiversity conservation, in partnership with Scottish Government and NatureScot. Read the rest of the series here.

Further reading

Finger, A., et al. 2011. Back from the brink: potential for genetic rescue in a critically endangered tree. Molecular Ecology 20: 3773—3784.

Finger, A., et al. 2012. Forest fragmentation genetics in a formerly widespread island tree: Vateriopsis seychellarum (Dipterocarpaceae). Molecular Ecology 21: 2369—2382.

Habel, J.C., et al. 2014. The relevance of time series in molecular ecology and conservation biology. Biological Reviews 89:484—492.

Frachon, N. 2018. An expedition to the Cairngorms to rescue the rare and endangered Alpine Sow-thistle. Botanic Stories. Edinburgh: Royal Botanic Garden Edinburgh.

Gamble, C., et al. (eds.). 2021. Seagrass Restoration Handbook: UK and Ireland. London: ZSL.

Finger, A., et al. 2022. Conservation genetics of montane willow populations in Scotland – limited natural recovery despite long-distance gene flow and high genetic diversity. Environmental Research: Ecology.