Polar, Mountain and Alpine Plants in Climate Change
Polar, mountain, and alpine regions are characterised by a short growing season with long day length, mostly cool temperatures, and rugged terrains. A relatively rich flora can still be found, especially in some of the Arctic regions, even if low shrubs, sedges, grasses, and mosses dominate. Antarctica currently supports only two native vascular plant species, but high numbers of mosses, lichens, and liverworts (Convey and Biersma 2024). Plant life in these areas has evolved to cope with rapidly fluctuating abiotic conditions across diurnal timeframes, but with consistent seasonal patterns (long winter and short growing season). However, climate change is strongly affecting seasonal patterns and is increasing the variability of short-term abiotic extremes, which may exceed the physiological capabilities of native plants in polar and mountainous regions. This special issue includes insights into plant response to cold extremes, plant adaptations across elevational gradients, plant response to drought and heat stress in field manipulations, as well as modelled carbon balance of Sphagnum peatlands, and how environmental pollutants influence plant responses to climate extremes and how this is mediated by fungal endophytes.
1 Cold Stress
Whilst growing in polar and mountainous regions, most vascular plants can cope with a certain level of freezing. However, even polar plants experience cold stress and may be irreparably damaged if freezing temperatures become too low. One of the two native Antarctic vascular plants, Colobanthus quitensis, appears highly vulnerable to a shift from −7.0°C to −9.0°C freezing, resulting in increased ion-leakage, lower antioxidant enzyme activities, and light harvesting (Min et al. 2024). Such temperatures are quite common during the growing season (Convey et al. 2018) and may underlie the scattered distribution of this species across Antarctic landscapes (Vera 2011) by using microhabitats to avoid freezing below −7°C. Plants may also include epigenetic modifications, such as methylation strategies, to induce a better stress response (Hereme et al. 2025). Finally, root symbionts help Antarctic vascular plants cope with environmental stresses (Acuña-Rodríguez et al. 2024).
2 Elevation Studies
Space for time substitution approaches can provide useful insights into plant adaptations to climate change predictions by comparing cold and warm sites, such as can be found along elevation gradients. Waseem et al. (2025) compared leaf hydraulic, gas exchange, and economic traits of 3391 woody plant species and showed that species growing at higher elevation possessed greater hydraulic safety, water use efficiency, but a conservative resource use strategy such as higher leaf mass per area, longer leaf lifespan, lower area-based leaf nitrogen and phosphorus contents, and lower rates of photosynthesis and dark respiration compared to species growing at lower elevation. These findings strengthen the patterns of other plant group adaptations across elevational gradients (Sundqvist et al. 2013; Roos et al. 2019; Yao et al. 2024), and the potential plant leaf trait responses to climate change.
Mangral et al. (2025) investigated the variation in gene expression patterns of Rhododendron anthopogon D. Don plants along an elevation gradient from 3200 to 3900 m in Kashmir Himalaya by using a comparative transcriptomics approach. A strong elevation-associated divergence in gene expression activity was detected, especially in genes associated with stress response (e.g., reactive oxygen species detoxification, adaptation to temperature fluctuations, and intense UV radiation) and secondary metabolism (such as flavonoid, terpenoid, and phenylpropanoid biosynthesis). The upregulation of genes involved in photosynthetic machinery (e.g., psbP.1, psaF.1) and ROS detoxification systems (e.g., L-ascorbate peroxidase, aldehyde oxidoreductase) at higher altitudes indicated an adaptive modulation of the photosynthetic apparatus and enhanced oxidative stress mitigation. Furthermore, the molecular analyses demonstrated the increased expression of cold-regulated genes, heat shock proteins, and enzymes related to the biosynthesis of fatty acids, which are crucial for membrane stability under cold and drought stress. These molecular insights underline how R. anthopogon orchestrates a complex and coordinated genetic response to thrive in the challenging and heterogeneous alpine environment, offering a crucial molecular basis for understanding climate resilience and adaptation strategies in high-altitude plant species. These results support those from earlier studies showing differences in the levels of stress-related gene expression and secondary metabolites at different altitudes (Liu et al. 2022; Kumar et al. 2023; Nong et al. 2023).
The vegetation in polar and mountainous regions also plays a role in the global carbon cycle and, as such, any adaptations of their photosynthetic capacity and respiration rates to climate change feed back to greenhouse gas-induced climate change. Perera-Castro and Nadal (2025) showed through seasonal modelling of the CO2 uptake and release of two Sphagnum species that day and night temperature oscillation, especially short night photoperiods, are potentially more important than the optimum temperature of photosynthesis for the carbon balance of Sphagnum peatlands (Perera-Castro and Nadal 2025).
3 Global Warming
Earth has warmed by approximately 1°C since the Industrial Revolution, while a higher temperature increase (by 2°–3°C) has been detected in the Arctic. The Antarctic, however, has experienced a more pronounced variation in mean annual temperatures than the Arctic, with a less obvious upward trend (Post et al. 2019). Nevertheless, an Earth warming of 2°–4°C in mean annual temperatures has been predicted for polar areas, which will have marked consequences on the polar ecosystems. Gago et al. (2025) used open-top chambers (OTC) to simulate the predicted warming effect to investigate molecular and eco-physiological changes in Antarctic field conditions in native vascular species Deschampsia antarctica and Colobantus quitensis. A significant impact was detected on the micro-environment and physiological responses in the plants grown under OTCs, indicating severe physiological stress responses related to drought and heat, but also more vigorous growth. However, the results indicated a high species-specific variation in responses to the OTC treatments between the two vascular species, which suggests that some native species can cope better with the environmental warming than others.
As described by the authors, this ‘double-edged sword’ effect highlights that while passive warming can initially seem beneficial, it can profoundly exacerbate drought and heat stress by significantly altering the micro-environment, including reduced soil moisture and increased extreme temperatures. For D. antarctica, this manifested as severe physiological stress, with marked reductions in photosynthetic capacity stemming from stomatal and mesophyll limitations, and a crucial decline in leaf mass per area which impacted dehydration tolerance. While D. antarctica showed a robust accumulation of osmoprotectants and secondary metabolites, these molecular adjustments were ultimately insufficient to fully mitigate the physiological impacts. In contrast, C. quitensis exhibited a more resilient response, likely attributable to its inherent smaller size and lower water demands. These findings provide critical insights into the differing vulnerabilities of Antarctic vascular plants and highlight how projected warming, particularly when coupled with drying, can push native species beyond their physiological coping limits, emphasising the need to consider complex stress interactions in future climate change predictions.
4 Pollutants and Environmental Extremes
Polar and mountainous regions are not only facing climate change but also pollution and biodiversity loss, which combined is often referred to as the triple planetary crisis. This means that in addition to changes in climate extremes, plants now have to face impoverished ecosystems that are accumulating more and more pollutants. A typical site-specific pollutant is that of oil spills from human habitation in polar and mountainous regions. Most eukaryotes are harmed by fuel spills in the field (Brown et al. 2023; Bi et al. 2025). However, Basilie Dazzi et al. (2025) show that a native Antarctic grass, Deschampsia antarctica, has a high tolerance for growing on diesel-contaminated soils. In fact, the results demonstrate the potential of D. antarctica for phytoremediation on Antarctic soils. The dose-responsive approach indicated that root growth was the most sensitive parameter responding to the contamination level; it could then be used as an indicator of diesel-induced stress for this species.
Moreover, Egas et al. (2025) show that fungal endophytes can help plants cope with stress-induced responses to persistent organic pollutants (POPs), which can have severe negative effects on the sensitive ecosystems of polar regions. In the study, Colobanthus quitensis populations growing along a latitudinal gradient 53°–67° S were exposed to POPs. The results showed symptoms of oxidative stress and altered eco-physiological performance in C. quitensis plants exposed to POPs. However, POPs-exposed C. quitensis associated with fungal endophytes showed lower lipid peroxidation, higher proline content, higher photosynthetic capacity, biomass, and survival percentage compared to plants without fungal endophytes. Interestingly, the plants growing in the most extreme conditions (67° S) with endophytic fungi presented the highest stress modulation upon POPs exposure. Thus, the results highlight the role of endophytic fungi in plant resistance, especially in extreme climate conditions such as in Antarctica.
Taken together, the nine papers in this special issue provide insights into the adaptation capabilities at physiological and molecular scales to changes in polar, mountain, and alpine environments. These areas with extreme growth conditions are among the most vulnerable to the ongoing environmental changes, including global warming and environmental pollution caused by human activities. Therefore, it is of utmost importance to develop new knowledge on the resilience of the ecosystems in these areas.
Finally, we thank all the contributing authors for their interest and commitment to this special issue.
Author Contributions
All authors have contributed to the writing of the Editorial.
