A multi-year experiment shows that lower precipitation predictability encourages plants' early life stages and enhances population viability

Abstract

Climate change is a key factor that may cause the extinction of species. The associated reduced weather predictability may alter the survival of plants, especially during their early life stages, when individuals are most fragile. While it is expected that extreme weather events will be highly detrimental for species, the effects of more subtle environmental changes have been little considered. In a four-year experiment on two herbaceous plants, Papaver rhoeas and Onobrychis viciifolia, we manipulated the predictability of precipitation by changing the temporal correlation of precipitation events while maintaining average precipitation constant, leading to more and less predictable treatments. We assessed the effect of predictability on plant viability in terms of seedling emergence, survival, seed production, and population growth rate. We found greater seedling emergence, survival, and population growth for plants experiencing lower intra-seasonal predictability, but more so during early compared to late life stages. Since predictability levels were maintained across four generations, we have also tested whether descendants exhibited transgenerational responses to previous predictability conditions. In P. rhoeas, descendants had increased the seedling emergence compared to ancestors under both treatments, but more so under lower precipitation predictability. However, higher predictability in the late treatment induced higher survival in descendants, showing that these conditions may benefit long-term survival. This experiment highlights the ability of some plants to rapidly exploit environmental resources and increase their survival under less predictable conditions, especially during early life stages. Therefore, this study provides relevant evidence of the survival capacity of some species under current and future short-term environmental alterations.