Impacts of warming and changes in precipitation frequency on the regeneration of two Acer species

ofthis century, and that more extreme rainfall events and longer intervening dry periods will take place.Climate change will likely affect all phases of the life cycle of plants, but plant reproduction has beensuggested to be especially sensitive. Here, using a combination of approaches (soil heaters and differentprovenances along a latitudinal gradient), we analyzed the regeneration from seeds of Acer platanoidesand A. pseudoplatanus, two tree species considered, from a management point of view, of secondary rel-evance. We studied germination, seedling survival and growth in a full-factorial experiment includingwarming and changes in watering frequency. Both species responded to warming, watering frequencyand seed provenance, with stronger (negative) effects of warming and provenance than of wateringfrequency. In general, the central provenances performed better than the northernmost and southern-most provenances. We also detected interactive effects between warming, watering frequency and/orseed provenance. Based on these results, both species are expected to show dissimilar responses to thechanges in the studied climatic factors, but also the impacts of climate change on the different phasesof plant regeneration may differ in direction and magnitude. In general increases in the precipitation,frequency will stimulate germination while warming will reduce survival and growth. Moreover, thefrequent divergent responses of seedlings along the latitudinal gradient suggest that climate change willlikely have heterogeneous impacts across Europe, with stronger impacts in the northern and southernparts of the species’ distribution ranges.