Interactive Warming and Drought Effects on the Regeneration of Acer pseudoplatanus and A. platanoides

CARÓN, MARÍA MERCEDES; VERHEYEN, KRIS; DE FRENNE, PIETER

Conferencia; ClimTree2013. International Conference on Climate Change and Tree Responses in Central European Forests; 2013

The sexual reproductive stage is considered an especially sensitive phase in the life cycle of plants in the face of climate change, but this phase also provides plants an opportunity to adapt to environmental changes. We analyzed the impact of different temperature and drought treatments on the sexual reproduction of Acer pseudoplatanus and A. platanoides from populations along a 2200 km long latitudinal gradient. A full factorial experiment was performed: germination, mortality, survival and growth were assessed under three temperature (+0°C, +2.7°C and +7.2°C) and three drought treatments (-0%, -20% and -40% soil moisture). Germination of A. platanoides decreased with drought but the effect was partially compensated by rising temperatures, while its mortality increased due to both warming and drought. In A. pseudoplatanus, the germination and the mortality decreased and increased following warming, respectively. In both species, warming and drought reduced all the biomass variables and increased the root:shoot ratio. We conclude that future warming might negatively affect the main variables that determine recruitment success (germination, seedling mortality and survival) while increasing drought events might negatively affect seedling growth. These two global-change drivers acting together may strongly modify the population dynamics of these two important tree species.