Here we assess intercontinental, long-term data on the phenological sensitivity of canopy and understory forest plants and the potential for phenological mismatch across temperate forests in North America, Europe, and Asia. It is similarly unknown whether understory herbaceous plant phenological sensitivity varies across large spatial and temporal scales. It is unknown, however, if the variation in woody plant phenology found in common garden experiments are also observed at large scales, for forest trees growing in their natal environment, and across long time periods 24. For example, Zohner and Renner 6, 23 have contributed valuable insights into interspecific variation in plant phenology using woody plants growing in European botanical gardens. Recent studies suggest that the duration of spring light windows in eastern North America is likely to be significantly altered with warming climates 7, 13, with herbaceous species generally expected to experience shorter spring light windows in the coming decades.Įxperimental evidence for such mismatches, however, has generally been limited to comparisons of woody plants located in common garden experiments, which are limited in geographical and temporal extent and have not evaluated mismatch with understory species. The success of this strategy to maximize the spring light window, referred to as “phenological escape” 12, 17, is directly associated with patterns of growth 10, 12, 17, 18, 19, survival 12, 18, 19, 20, flowering 17, 20, and reproductive output 10, 17, 21, 22. This potential phenological mismatch is important because spring-active wildflowers in temperate deciduous forests, as well as some woody understory species 12, 13, 14, 15, often rely on leafing out before the canopy closes in order to assimilate 40–100% of their annual carbon budget 16. Herbaceous plants may be less sensitive to spring temperature than trees because the former often overwinter underground and, therefore, may not respond to the same phenological cues as the latter, which have extensive aboveground structures 10, 11, but this mechanism has only been studied in North American forests. Evidence in Europe similarly suggests differences in sensitivities between woody and herbaceous plants 8, 9. Previous studies indicate differences in spring phenological sensitivity between woody and herbaceous plants in forests, with direct comparisons available for plants in Asia 3 and North America 5, 7. Furthermore, recent research has found disparities in phenological sensitivity among plants from different continents 2, 6, suggesting that climate change may affect temperate forests differently depending on location. They are characterized by winter-deciduous plant species, and the phenology of leaf out and flowering on all three continents is sensitive to variation in average spring temperature 2, 3, 4, 5. Temperate deciduous forests are a dominant biome in the northern hemisphere, covering extensive regions in eastern Asia, continental Europe, and eastern North America 1. We predict that advancing tree phenology will lead to decreasing spring light windows in North America while spring light windows will be maintained or even increase in Asia and Europe in response to projected climate warming. Here, we use herbarium specimens to show that phenological sensitivity to spring temperature is remarkably conserved for understory wildflowers across North America, Europe, and Asia, but that canopy trees in North America are significantly more sensitive to spring temperature compared to in Asia and Europe. The study of this dynamic, commonly referred to as “phenological escape”, and its sensitivity to spring temperature is limited to eastern North America. Recent work suggests that spring ephemeral wildflowers may be at additional risk due to phenological mismatch with deciduous canopy trees. Temperate understory plant species are at risk from climate change and anthropogenic threats that include increased deer herbivory, habitat loss, pollinator declines and mismatch, and nutrient pollution.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |