Flowering phenology in a species-rich temperate grassland is sensitive to warming but not elevated CO2

Authors


Author for correspondence:
Mark J. Hovenden
Tel:+61 3 6226 7874
Fax:+61 3 6226 2698
Email: Mark.Hovenden@utas.edu.au

Summary

  • • Flowering is a critical stage in plant life cycles, and changes might alter processes at the species, community and ecosystem levels. Therefore, likely flowering-time responses to global change drivers are needed for predictions of global change impacts on natural and managed ecosystems.
  • • Here, the impact of elevated atmospheric CO2 concentration ([CO2]) (550 µmol mol−1) and warming (+2ºC) is reported on flowering times in a native, species-rich, temperate grassland in Tasmania, Australia in both 2004 and 2005.
  • • Elevated [CO2] did not affect average time of first flowering in either year, only affecting three out of 23 species. Warming reduced time to first flowering by an average of 19.1 d in 2004, acting on most species, but did not significantly alter flowering time in 2005, which might be related to the timing of rainfall. Elevated [CO2] and warming treatments did not interact on flowering time.
  • • These results show elevated [CO2] did not alter average flowering time or duration in this grassland; neither did it alter the response to warming. Therefore, flowering phenology appears insensitive to increasing [CO2] in this ecosystem, although the response to warming varies between years but can be strong.

Ancillary