Ecophysiological traits of a clonal grass in its climate change response

Background Understanding the ability of species to respond to climate change is essential for prediction of their future distribution. When migration is not adequate, reaction via phenotypic plasticity or genetic adaptation is necessary. While many studies investigated the importance of plasticity and genetic differentiation (plant origin) in growth related traits, we know less about differentiation in ecophysiological traits. In addition, the existing studies looking at plant physiology usually do not estimate the consequences of these physiological changes for species performance. Methods We used a clonal grass Festuca rubra originating from localities representing factorially crossed gradients of temperatures and precipitations. We cultivated the plants in growth chambers set to simulate temperature and moisture regime in the four most extreme localities. We measured net photosynthetic rate, chlorophyll fluorescence, SLA, osmotic potential, stomatal density and stomatal length as range of ecophysiological traits and tested their relationship to plant fitness measured as ramet number and biomass. Key results We found strong phenotypic plasticity in photosynthetic traits and genetic differentiation in stomatal traits. In most traits, the effects of temperature interacted with the effects of moisture. The relationship between the ecophysiological and fitness-related traits was significant but weak. Conclusions Ecophysiological response of Festuca rubra to climate change is driven by phenotypic plasticity as well as by genetic differentiation indicating potential ability of the populations to adapt to new climatic conditions. The changes in ecophysiological traits translate into plant fitness even though other unmeasured factors also play an important role in fitness determination. Inclusion of species ecophysiology into studies of species adaptation to climate can still increase our ability to understand how species may respond to novel conditions.