Abstract Detail


Shamek, Jess [1], Kautz, Stefanie [2], Ballhorn, Daniel [2].

Adaptive plasticity of Quercus garryana seedlings under drought and warming.

In a future of catastrophic climate change, phenotypic plasticity will be crucial for long-lived plants such as forest trees to respond relatively quickly to their changing environment. Understanding these responses is necessary for predicting and managing the effects of climate change but species-specific knowledge of phenotypic plasticity in many forest trees is lacking. Oaks (Quercus) have recently been identified as a model clade for investigating the ecological and evolutionary response of plants to environmental changes. In the Northern hemisphere, they are a keystone genus for Lepidoptera and are notable for how much above ground carbon they store. Oregon white oak, Quercus garryana, is the representative species of a rare grassland ecosystem and is expected to expand and shift its range in the coming decades, outcompeting less heat and drought tolerant tree species. This ecosystem is found in many urban and peri-urban areas across the West coast of North America and will be of utmost importance for maintaining ecosystem services with future climate change. However, little is known about the adaptive plasticity (phenotypic plasticity that improves the fitness of genotypes) of this species in response to climate change variables such as heat and drought. Here we present results from a climate factorial experiment of Q. garryana seedlings collected from the Portland Metro region in Oregon. Oak acorns were collected from two regional parks and grown in pots. In June of 2020, seedlings were placed in open top chambers, rain-out shelters, or a combination of both. Temperature and relative humidity were tracked using HOBO data loggers in the center of each treatment. In addition, a subset of trees were grown with no treatment in a control group. Tree seedlings were grown for 18 months and sampled in the fall of 2021 for a suite of traits including specific leaf area, height, biomass, and root to shoot ratio. PERMANOVA results indicate significant differences in the biomass and root to shoot biomass ratio of these tree seedlings by site, treatment, and site by treatment. Trees grown under elevated temperature had significantly greater biomass than those grown with 30% reduction in ambient precipitation and in the control. This response varied by site. The combination of drought and warming had a constraining effect on biomass which also varied by site. The warming and combination of drought and warming treatments showed a significant decrease in root to shoot biomass ratio. Our results confirm what others have found, that this species is heat and drought tolerant. Our results further indicate that these populations may have the adaptive plasticity necessary to persist in a future of catastrophic climate change but that provenance will shape this response.

1 - 333 SE 148TH AVE, PORTLAND, OR, 97233, United States
2 - Portland State University, Department of Biology, 1825 SW Broadway, Portland , OR, 97210, USA

Phenotypic plasticity
climate change
adaptive traits

Presentation Type: Oral Paper
Number: EC05005
Abstract ID:986
Candidate for Awards:None

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