Dr Jan Dick, who carries out transdisciplinary research at UKCEH, reflects on how long-term monitoring and international collaboration provide important insights into how climate change is affecting the ecology of the Cairngorms and other European mountains...
The recent wildfires in the Cairngorms have highlighted how vulnerable mountain ecosystems are becoming to a changing climate. While such dramatic events capture public attention, many of the most profound changes occurring higher in mountain landscapes are far less visible. These changes unfold gradually over decades, detectable only through sustained, long-term monitoring.
For more than 20 years, UKCEH researchers have contributed to the Global Observation Research Initiative in Alpine Environments (GLORIA), monitoring four mountain tops in the Cairngorms. Working alongside universities, research institutes and conservation organisations across Europe, all using a shared monitoring protocol, scientists repeatedly survey the same mountain summits, creating one of the world's most comprehensive records of climate-driven ecological change.
This international collaboration allows us to understand not only what is happening in the Cairngorms, but how these changes compare with mountain ecosystems across Europe
One of the clearest messages emerging from the GLORIA network is that mountain plant communities are becoming increasingly dominated by species associated with warmer conditions, a shift seen consistently across European mountain summits. Crucially, climate warming alone doesn't fully explain it, local factors like soil type and which colonising species happen to be nearby also shape how a summit responds. Untangling that mix is only possible because GLORIA applies the same protocol at over 60 summits sampling hundreds of vegetation plots, rather than relying on any single study (Hausharter et al., 2026).
Greener isn’t better
The clearest expression of this warming signature is physical: shrubs are spreading. Vegetation records from hundreds of plots across Europe's mountain ranges show shrub cover increasing consistently over the past two decades, in many regions simultaneously, a continental response, not a local anomaly. That matters well beyond aesthetics. Denser shrub cover changes snow retention, adds to the fuel loading, alters soil temperatures through the seasons, and reshapes nutrient cycling and habitat structure for everything else living there (Vanneste et al., 2026)
At first glance, greener mountain landscapes might appear to indicate ecological recovery or increasing biodiversity. However, the long-term records tell a more nuanced story. While mountain summits are gaining new species, local extinction rates are also increasing. Cold-adapted plants that characterise high-altitude environments are increasingly disappearing from monitored sites, particularly in areas experiencing stronger climate warming and greater shifts towards warm-adapted communities. Without the long-term monitoring efforts of scientists, these losses could easily remain hidden beneath overall increases in species richness (Wessely et al, 2026).
Different ecosystems, different responses
Placing these mountain trends within a broader European context, mountain summits are responding more rapidly to climate change than other ecosystem types, including forests and grasslands. Importantly, alpine summit communities are accruing ‘climatic debts’, falling behind the pace of climate change faster than these other ecosystems, as they are unable to keep pace with how quickly conditions are shifting. This lag suggests that many future ecological changes are already set in motion, even if climate warming were to slow (Yue et al, 2026).
What this means for the Cairngorms
These are not abstract, far-off findings. They describe the mountains outside Aviemore and Braemar as directly as they describe the Alps or the Pyrenees.
For wildlife, the losers are the specialists that have nowhere left to go. Species that depend on the cold, open, low-shrub summit habitat that GLORIA's plots are tracking face habitat that is shrinking from below, as warm-adapted, shrubbier communities move upslope. Unlike species in larger continental mountain ranges, Scotland's montane specialists are already close to the top of the country's highest ground, there is very little "further up" left to retreat to.
For people, the risks are more immediate than they might seem. Shifting vegetation touches the things that draw people to the Cairngorms in the first place: hillwalking, wildlife tourism, and a landscape whose character is defined by openness as much as by scenery. It also connects, at least plausibly, to the wildfire risk the region experienced firsthand this summer. None of these are hypothetical future concerns, they are consequences of a shift that has been under way, and measured, for 20 years.
Power of long-term monitoring
What makes these findings particularly powerful is not any single study, but the collective effort behind them. The GLORIA network brings together researchers from dozens of institutions across Europe who use the same methods, revisit the same plots, and share data across national boundaries. UKCEH's Cairngorms sites represent an important part of this research. By combining observations from Scotland with data from mountain regions spanning Europe, scientists can identify continent-wide patterns that would be impossible to detect at a single location.
As the recent Cairngorms wildfires remind us, mountain ecosystems are facing increasing pressures from climate change. Long-term monitoring cannot prevent these changes, but it provides the evidence needed to understand them, anticipate future risks, and support informed decisions about conservation and land management. The value of these datasets grows with every survey, offering insights that only decades of collaboration, commitment and consistent observation can deliver.
In an age of rapid environmental change, long-term ecological monitoring is more important than ever. The story emerging from Europe's mountain summits is not simply one of warming temperatures. It is a story of ecosystems being reshaped, species adapting and disappearing, and an international community of researchers working together to understand what these changes mean for the future of our mountain landscapes.
References
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Hausharter, J. et al, 2026. Widespread thermophilization but weak link to climate warming in Europe's summit plant communities. Nature Ecology & Evolution. DOI: 10.1038/s41559-026-03150-x
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Vanneste, T. et al, 2026. Widespread shrubification on European mountain summits. Global Change Biology. DOI: 10.1111/gcb.70786.
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Wessely, J. et al, 2026. Rising plant extinction rates on European mountain summits. Science. DOI: 10.1126/science.aed2974.
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Yue, K. et al, 2026. Contrasting thermophilization among forests, grasslands and alpine summits. Nature. DOI: 10.1038/s41586-025-09622-7.
These insights would not have been possible without the long-term investment provided by UKCEH National Capability funding from the Natural Environment Research Council award NE/Y006208/1) and NatureScot which help sustain the UK Environmental Change Network site and wider environmental monitoring in the Cairngorms. The MICROCLIM project funded the 2022 resurvey of the GLORIA plots.