Mountain Greening Threatens Genetic Diversity of Key Alpine Plants, Study Finds

Mountains are among the most biodiverse ecosystems on Earth, yet global environmental changes are profoundly reshaping them. Over the past 50 years, rising temperatures and shifts in land use have driven the expansion of shrubs and trees—a phenomenon known as "mountain greening." This has led to the gradual disappearance of unique low-growing alpine meadow species. One such species under threat is the medicinally valuable Sideritis (commonly known as Greek mountain tea), a key indicator of mountain ecosystem health in the Mediterranean region.

A recent study, integrating satellite remote sensing with genetic analysis, has revealed a direct link between mountain greening and the loss of genetic diversity.

Researchers examined Sideritis populations across 11 mountain ranges in Greece, comparing genetic data from 1970s herbarium specimens with contemporary samples. They found a significant decline in genetic diversity in eight of the regions, with some populations showing inbreeding coefficients as high as 20%—an indicator of population shrinkage. Satellite imagery confirmed that increased vegetation density correlates with reduced genetic diversity, suggesting that expanding competitive species are crowding out native flora.

Conducted by Germany's Senckenberg Biodiversity and Climate Research Center, the National Observatory of Athens, and the University of Copenhagen, the study warns that genetic erosion undermines a species' ability to adapt to environmental changes and raises extinction risks. The researchers highlight that their novel approach allows genetic diversity to be monitored via satellite, offering a powerful tool for assessing biodiversity in remote or inaccessible mountainous areas.

The study further underscores that mountain greening is a widespread global trend and recommends prioritizing conservation efforts in the most affected regions. It also calls for expanded research to better understand the full impact of environmental change on biodiversity.