Abstract Detail


Lee, Ben [1], Miller, Tara [2], Rosche, Christoph [3], Yong, Yang [4], Heberling, Mason [5], Kuebbing, Sara [6], Primack, Richard [7].

Tree-wildflower phenological mismatch differs across continents in response to spring warming.

Understory forest plants are strongly limited by access to light throughout the growing season, and many species in deciduous forests have evolved strategies to make use of ephemeral, seasonally-dynamic light availability. However, anthropogenic activities are fundamentally changing the forest light regimes to which native species have adapted: warmer springs are shifting phenology of co-occurring species at different rates (and sometimes in different directions), leading to phenological mismatch. Well-studied with respect to plant-pollinator mismatch, there is a growing body of literature exploring plant-plant mismatch, particularly as it relates to the timing of overstory and understory phenology in temperate deciduous forests. There is high potential for phenological disruption in plant-plant interactions as demonstrated by studies at small geographical scales, but broad geographical patterns, and their ecological consequences, are only partially understood.             Here, we scored wildflower and canopy tree herbarium specimens from temperate forests in North America, Europe, and east Asia in an effort to identify if phenological sensitivity to spring temperature differs between the two groups and among the three continents. We also investigated whether and how the inclusion of spatial autocorrelation in phenology models, which has recently been shown to improve predictive capacity for herbarium-based studies, affect our results and conclusions.             Understory wildflowers and canopy tree species were both significantly sensitive to spring temperature, with sensitivities ranging from -2.3 to -3.5 days/°C. Phenological sensitivity did not significantly differ between wildflowers and trees on any continent in the best-fit models, contrary to previous studies which have documented greater sensitivity for trees compared to forbs (and thus projections of reduced access to light availability under climate change conditions). Instead, we found almost equal sensitivity in North America and relatively greater sensitivity for wildflowers compared to trees in Europe and Asia. This suggests that wildflowers on the latter two continents will instead gain access to spring light under warming springs.              Importantly, we found that spatial autocorrelation significantly improved model fit (using DIC) across the board and found vast improvements in the correlation between predictions and observations. However, its inclusion also considerably changed the direction and magnitude of our predictions. For example, without spatial autocorrelation, our models estimate that North American trees are significantly more sensitive to spring temperature compared to wildflowers, consistent with results from previous studies. Our results suggest that 1) spatial autocorrelation is important for herbarium-based phenological models, 2) overstory/understory mismatch differs across continents, and 3) climate change will affect access to understory light in different ways.

1 - Carnegie Museum of Natural History, Section of Botany, 4400 Forbes Ave, Pittsburgh, PA, 15213, USA
2 - Boston University, Biology, 5 Cummington Mall, Boston, MA, 02215, United States
3 - Martin-Luther-University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden, Halle, Germany
4 - Nanjing Forestry University, Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, 159 Longpan Rd., Nanjing, 210037, China
5 - Carnegie Museum Of Natural, Section Of Botany, 4400 Forbes Ave, Pittsburgh, PA, 15213, United States
6 - Yale University, Applied Science Synthesis Program, New Haven, CT, 06511, USA
7 - DEPARTMENT OF BIOLOGICAL SCIENCES, 5 Cummington Mall, Boston, MA, 02215, United States

phenological escape
leaf out
spatial autocorrelation
temperate forest
integrated nested laplace approximation (INLA)
climate change.

Presentation Type: Oral Paper
Number: EC05006
Abstract ID:89
Candidate for Awards:None

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