Sarah Watts

Upland plant ecologist, University of Stirling

For 40 years the National Trust for Scotland has been monitoring nationally rare species at Ben Lawers NNR, the most important site for arctic-alpine plants in Britain. Sarah worked here as an ecologist from 2013-2020.

nts.org.uk

“The arctic-alpine flora of Britain’s mountains is of international significance, as it contains many rare plant species at the southern edge of their worldwide range. These populations can be genetically unique and are crucial for maintaining biodiversity. Our upland plants provide the foundation for mountain habitats, supporting rare invertebrates, and birds such as ptarmigan and ring ouzel.

“There is a wealth of evidence suggesting an increasing homogeneity of upland vegetation in Britain – ie plant communities are becoming more similar in composition, as arctic-alpine specialists decline and lowland generalists increase due to climate change. Those already found on mountaintops have nowhere else left to go as temperatures rise and snow cover declines. Snow is thought to be critically important because it protects alpine habitats from erosive forces such as freeze-thaw cycles, landslip, rock falls or grazing animals, while also suppressing more vigorous, competitive plants by shortening the growing season.

“I’ve witnessed first-hand the vegetation changes taking place. Just roughly 2360 snow pearlwort plants are left in Britain, with all but 18 located within Ben Lawers NNR. This species is being lost from its lowest altitude sites and now only grows above 915m.

“These are some of Britain’s most challenging species to study due to their rarity and high altitude locations, but also because they can only be identified by experienced botanists. Long-term monitoring is crucial for detecting trends and developing conservation policies in the face of climate change. It is vital that such knowledge is retained, and that the plight of our declining flora is not overlooked.”