Abstract Detail


Dawson, Hilary Rose [1], Maxwell, Toby [2], Bridgham, Scott [1], Reed, Paul [1], Silva, Lucas [1].

Morphological and functional leaf trait responses to experimental drought in Pacific Northwest grasslands.

The Pacific Northwest is predicted to face greater drought conditions in the near future, conditions which are expected to negatively impact grassland productivity and essential ecosystem functions (e.g. carbon sequestration and food production). It remains uncertain, however, if persistent drought stress alters the relationship between plant form and function. We analyzed data from a long-term experiment focusing on growth form and its relationship with two critical species functions, water and nutrient stoichiometry, for 12 different plant species. By analyzing morphological and functional traits including specific leaf area (SLA), water use efficiency (iWUE), and leaf C:N in plants grown in control and simulated drought conditions (i.e. in replicated control vs. rain exclusion plots) at three different sites spanning a 520 km latitudinal gradient, we identified unexpected responses to drought. Specifically, we found a significant negative correlation between SLA and iWUE (R2 = 0.67, p < 0.0001). Perennials were at the high end of this spectrum with high iWUE and low SLA while annuals were at the low end with a low iWUE and high SLA. No relationship was observed for SLA and C:N (p >> 0.05). Rain exclusion treatment had no consistent effect on the traits across all sites. SLA ranged from 0.056 to 0.322 cm2/mg, iWUE ranged from 11.86 to 96.21 mmol/mo, and C:N ranged from 9.11 to 69.92. Overall, perennial plants were on average 41% more water efficient than annuals and grasses 45% more efficient than forbs, while perennial grasses were 102% more efficient than the annual forbs, with small variations in response to rain exclusion (decrease of up to 10% between treatment and control plots) within sites. In conclusion, we found that three years of experimental drought did not alter plant form-function relationship.

1 - Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403, USA
2 - Boise State University, Boise, ID, 83725, USA

none specified

Presentation Type: Poster
Session: P, Ecophysiology Posters
Location: Virtual/Virtual
Date: Tuesday, July 28th, 2020
Time: 5:00 PM Time and date to be determined
Number: PPE007
Abstract ID:423
Candidate for Awards:None

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