(2016). Day length unlikely to constrain climate-driven shifts in leaf-out times of northern woody plants. Nature Climate

Late-spring frosts (LSFs) affect the performance of plants and animals across the world’s temperate and boreal zones, but despite their ecological and economic impact on agriculture and forestry, the geographic distribution and evolutionary impact of these frost events are poorly understood. Here, we analyze LSFs between 1959 and 2017 and the resistance strategies of Northern Hemisphere woody species to infer trees’ adaptations for minimizing frost damage to their leaves and to forecast forest vulnerability under the ongoing changes in frost frequencies. Trait values on leaf-out and leaf-freezing resistance come from up to 1,500 temperate and boreal woody species cultivated in common gardens. We find that areas in which LSFs are common, such as eastern North America, harbor tree species with cautious (late-leafing) leaf-out strategies. Areas in which LSFs used to be unlikely, such as broad-leaved forests and shrublands in Europe and Asia, instead harbor opportunistic tree species (quickly reacting to warming air temperatures). LSFs in the latter regions are currently increasing, and given species’ innate resistance strategies, we estimate that ∼35% of the European and ∼26% of the Asian temperate forest area, but only ∼10% of the North American, will experience increasing late-frost damage in the future. Our findings reveal region-specific changes in the spring-frost risk that can inform decision-making in land management, forestry, agriculture, and insurance policy.

Despite their extent and socio-ecological importance, a comprehensive biogeographical synthesis of drylands is lacking. Here we synthesize the biogeography of key organisms (vascular and nonvascular vegetation and soil microorganisms), attributes (functional traits, spatial patterns, plant-plant and plant-soil interactions) and processes (productivity and land cover) across global drylands. These areas have a long evolutionary history, are centers of diversification for many plant lineages and include important plant diversity hotspots. This diversity captures a strikingly high portion of the variation in leaf functional diversity observed globally. Part of this functional diversity is associated with the large variation in response and effect traits in the shrubs encroaching dryland grasslands. Aridity and its interplay with the traits

Intuitively, interannual spring temperature variability (STV) should influence the leaf-out strategies of temperate zone woody species, with high winter chilling requirements in species from regions where spring warming varies greatly among years. We tested this hypothesis using experiments in 215 species and leaf-out monitoring in 1585 species from East Asia (EA), Europe (EU) and North America (NA). The results reveal that species from regions with high STV indeed have higher winter chilling requirements, and, when grown under the same conditions, leaf out later than related species from regions with lower STV. Since 1900, STV has been consistently higher in NA than in EU and EA, and under experimentally short winter conditions NA species required 84% more spring warming for bud break, EU ones 49% and EA ones only 1%. These previously unknown continental-scale differences in phenological strategies underscore the need for considering regional climate histories in global change models.

24Aim Quaternary palaeopalynological records collected throughout the Iberian Peninsula and 25 species distribution models (SDMs) were integrated to gain a better understanding of the 26 historical biogeography of the Iberian Abies species (i.e. Abies pinsapo and Abies alba). We 27 hypothesize that SDMs and Abies palaeorecords are closely correlated, assuming a certain 28 stasis in climatic and topographic ecological niche dimensions. In addition, the modelling 29 results were used to assign the fossil records to A. alba or A. pinsapo, to identify environmental 30 variables affecting their distribution, and to evaluate the ecological segregation between the 31 two taxa. propose that the two taxa remained isolated throughout the Quaternary, indicating a significant 44 geographical and ecological segregation. In addition, no significant differences were detected 45 comparing the three projections (present-day, Mid-Holocene and LGM), suggesting a relative 46 climate stasis in the refuge areas during the Quaternary. 47 Main conclusions Our results confirm that SDM projections can provide a useful complement 48to palaeoecological studies, offering a less subjective and spatially explicit hypothesis 49 concerning past geographic patterns of Iberian Abies species. The integration of ecological-50 niche characteristics from known occurrences of Abies species in conjunction with 51 palaeoecological studies could constitute a suitable tool to define appropriate areas in which to 52 focus proactive conservation strategies. 53 54