Differentiated Responses of Apple Tree Floral Phenology to Global Warming in Contrasting Climatic Regions

Abstract

The responses of flowering phenology to temperature increases in temperate fruit trees have rarely been investigated in contrasting climatic regions. This is an appropriate framework for highlighting varying responses to diverse warming contexts, which would potentially combine chill accumulation (CA) declines and heat accumulation (HA) increases. To examine this issue, a data set was constituted in apple tree from flowering dates collected for two phenological stages of three cultivars in seven climate-contrasting temperate regions of Western Europe and in three mild regions, one in Northern Morocco and two in Southern Brazil. Multiple change-point models were applied to flowering date series, as well as to corresponding series of mean temperature during two successive periods, respectively determining for the fulfillment of chill and heat requirements. A new overview in space and time of flowering date changes was provided in apple tree highlighting not only flowering date advances as in previous studies but also stationary flowering date series. At global scale, differentiated flowering time patterns result from varying interactions between contrasting thermal determinisms of flowering dates and contrasting warming contexts. This may explain flowering date advances in most of European regions and in Morocco vs. stationary flowering date series in the Brazilian regions. A notable exception in Europe was found in the French Mediterranean region where the flowering date series was stationary. While the flowering duration series were stationary whatever the region, the flowering durations were far longer in mild regions compared to temperate regions. Our findings suggest a new warming vulnerability in temperate Mediterranean regions, which could shift toward responding more to chill decline and consequently experience late and extended flowering under future warming scenarios.

Can phenological models predict tree phenology accurately in the future? The unrevealed hurdle of endodormancy break

“…). Premises of endodormancy break failure, that is lack of chilling delaying endodormancy break and subsequently budburst date, are actually already visible in long‐term phenological series of apple tree in Nîmes (Legave et al ., ). Endodormancy break failure has been shown to be responsible for local population extinction at species southern range margins in previous modeling studies (Morin et al ., ).…”

Corner's rules as a framework for plant morphology, architecture and functioning – issues and steps forward

“…proximity of neighboring plants) environments have a cumulative effect on tree morphology and architecture over consecutive growing seasons. It has been shown that besides their effect on budburst phenology (Legave et al ., ) mild winter temperatures compared to cold winter temperatures significantly decrease branching frequency on stems with similar size and shape (e.g. apple, Dutra Schmitz et al ., ).…”

Different ways to die in a changing world: Consequences of climate change for tree species performance and survival through an ecophysiological perspective

“…Such changes can have a devastating impact on the composition of several plant communities because changes in flowering time may, for instance, induce mismatches between plants and their respective pollinators and thereby compromise the reproduction and distribution of several species (Becklin et al, 2016;Polce et al, 2014;Springer & Ward, 2007). These results are even more worrying when we also consider the increase in global average temperature, another factor that has been directly associated with phenological changes in many species (Bock et al, 2014;Legave, Guédon, Malagi, Yaacoubi, & Bonhomme, 2015;Mulder, Iles, & Rockwell, 2017). Thus, it is clear that the effect of high [CO 2 ] on the performance, survival, and distribution of species worldwide represents one of the greatest uncertainties related to climate change because its effects are extremely variable and also depend on a range of other factors.…”