Recent changes in high-mountain plant community functional composition in contrasting climate regimes

Area of Science:

• Ecology
• Climate Change Biology
• Plant Community Ecology

Background:

• High-mountain plant communities are sensitive to abiotic factors, particularly temperature, making them vulnerable to climate warming.
• Rising temperatures increase evapotranspiration and alter precipitation, potentially causing severe water deficiencies in alpine ecosystems.
• Understanding these impacts requires comparing plant communities across diverse climatic gradients.

Purpose of the Study:

• To compare alpine plant communities along elevation and water availability gradients in the Alps, Apennines, and Crete.
• To identify relationships between community indices (traits, cover, diversity) and soil temperature/snow duration.
• To assess vegetation changes over a 14-year period (2001-2015) in response to climate change.

Main Methods:

• Field study comparing alpine plant communities across three distinct regions: NE-Alps (humid), Central Apennines (moderate), and Lefka Ori, Crete (summer-dry).
• Analysis of community-based indices: plant functional traits (Leaf Dry Matter Content, Specific Leaf Area), thermic vegetation indicator, life forms, vegetation cover, and diversity.
• Correlation with abiotic factors: soil temperature and snow duration, and temporal analysis of changes over 14 years.

Main Results:

• Plant community indices responded to temperature gradients in the Alps and Apennines, but this effect diminished in dry Crete, indicating a shift to drought as the primary filter.
• Leaf trait responses varied, suggesting drought impacts are evident even in the northern Mediterranean.
• Vegetation cover increased slightly across all regions; thermophilisation occurred in the Alps and Apennines, with declines in cold-adapted plants and increases in shrubs on Crete.

Conclusions:

• Alpine vegetation is shifting from temperature-driven to drought-driven dynamics, particularly in drier Mediterranean regions.
• While significant biodiversity loss is not yet observed, ongoing monitoring is crucial due to the threat to vulnerable alpine flora.
• Combined warming and drought impacts necessitate intensified monitoring for threatened alpine plant species, especially those in southern, dry areas or poorly adapted to drought in the north.