Climate change effects on snow cover and thermic regime in alpine tundra might lead to a longer growing season, but could also increase risks to plants from spring frost events. Alpine snowbeds, i.e. alpine tundra from late snowmelt sites, might be particularly susceptible to such climatic changes. Snowbed communities were grown in large monoliths for two consecutive years, under different manipulated snow cover treatments, to test for effects of early (E) and late (L) snowmelt on dominant species growth, plant functional traits, leaf area index (LAI) and aboveground productivity. Spring snow cover was reduced to assess the sensitivity of snowbed alpine species to severe early frost events, and dominant species freezing temperatures were measured. Aboveground biomass, productivity, LAI and dominant species growth did not increase significantly in E compared to L treatments, indicating inability to respond to an extended growing season. Edapho-climatic conditions could not account for these results, suggesting that developmental constraints are important in controlling snowbed plant growth. Impaired productivity was only detected when harsher and more frequent frost events were experimentally induced by early snowmelt. These conditions exposed plants to spring frosts, reaching temperatures consistent with the estimated freezing points of the dominant species (similar to-10 degrees C). We conclude that weak plasticity in phenological response and potential detrimental effects of early frosts explain why alpine tundra from snowbeds is not expected to benefit from increased growing season length.
- Alopecurus gerardi
- alpine tundra
- Carex foetida
- early frost
- growing season length
- Poa alpina
- SIMULATED CLIMATE-CHANGE
- FLOWERING PHENOLOGY
- EUROPEAN ALPS
- ARCTIC TUNDRA
[Baptist, F.; Flahaut, C.; Choler, P.] Univ Grenoble, Lab Ecol Alpine, CNRS UJF, UMR 5553, F-38041 Grenoble 09, France; [Streb, P.] Univ Paris Orsay, UFR Sci Orsay, Lab Ecol Systemat & Evolut, Orsay, France; [Choler, P.] Univ Grenoble, Stn Alpine J Fourier, CNRS UJF, UMR 2925, F-38041 Grenoble 09, France
Baptist, F (reprint author), Univ Grenoble, Lab Ecol Alpine, CNRS UJF, UMR 5553, BP 53, F-38041 Grenoble 09, France.
- Ecologie, systématique et évolution (ESE), UMR8079
- Laboratoire d'écologie alpine (LECA), UMR5553
- Station alpine Joseph Fourier (SAJF), UMS3370