Glacial survivors on sunny slopes

The Sierra Nevada mountains of southern Spain are a biodiversity hotspot, containing over 2,100 species of vascular plants. During the last Ice Age, many plant species moved south to escape the cold, finding refuge in the comparatively warm Mediterranean region. As the climate warmed again during the Holocene (the last 11,700 years), some species migrated back north, while others retreated to higher altitudes in the mountains, adapting to the new conditions. This process turned the high peaks into isolated "sky islands."

These mountains contain pockets called microrefugia. The complex terrain creates climatic contrasts; sunny, dry south-facing slopes differ greatly from the cooler, wetter north-facing slopes. These shaded, north-facing slopes supported cold-adapted flora. Genetic studies on several alpine plant species confirm their long-term isolation and survival in these specific locations. Analysis of amplified fragment length polymorphisms (AFLPs) shows distinct genetic groups corresponding to different mountain ranges, a result of populations being separated as post-glacial warming progressed from south to north. This evidence indicates that these plant populations have been isolated here for thousands of years, surviving climatic shifts when the surrounding lowlands became inhospitable.

A living botanical museum

The Sierra Nevada has about 80 endemic plant species, meaning they are found nowhere else on Earth. The percentage of endemic species increases with elevation. Many of these unique plants are found above 2,300 meters in marshy, high-altitude grasslands called borreguiles or on steep, rocky slopes known as canchales.

One relict species is a subspecies of Scots Pine, Pinus sylvestris nevadensis, which is endemic to these mountains. This tree can grow up to 30 meters tall and remains from a time when the climate was much colder. Another famous plant is the Sierra Nevada violet. One of the most famous endemics is the "snow star," Plantago nivalis, a plant that grows only above 3,000 meters and is adapted to extreme temperatures. Genetic research on species like Linaria glacialis suggests that while future warming will cause their ranges to contract severely, their genetic diversity may not diminish at the same pace, thanks to large effective population sizes and gene flow. These high-altitude ecosystems are sites for studying plant adaptation and survival through dramatic climate change.

Practical Information

Opening Hours

The Sierra Nevada National Park is open 24/7, year-round, but access to high-altitude areas depends on weather and snow conditions. Spring and early summer are ideal for seeing the flora.

Admission

Free.

Accessibility

The terrain is mountainous. Many areas with relict flora are in high-altitude zones accessible only via strenuous hiking on rugged trails. Some lower-altitude areas and botanical gardens, like La Cortijuela, have easier walking paths.

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18,000-Year-Old Glacial Gardens

Glacial survivors on sunny slopes

A living botanical museum

💡Fun Facts

References

There's more in the app

Practical Information

18,000-Year-Old Glacial Gardens

Glacial survivors on sunny slopes

A living botanical museum

💡Fun Facts

References

There's more in the app

Practical Information

Nearby curiosities

Nearby curiosities