Earlier plant growth helps compensate for reduced carbon fixation after 13 years of warming

Functional Ecology
By: , and 

Links

Abstract

1. Drylands play a dominant role in global carbon cycling and are particularly vulnerable to increasing temperatures, but our understanding of how dryland ecosystems will respond to climatic change remains notably poor. Considering that the area of drylands is projected to increase 11–23% by 2100, understanding the impacts of warming on the functions and services furnished by these arid and semiarid ecosystems has numerous implications.

2.In a unique 13‐year ecosystem warming experiment in a southwestern U.S. dryland, we investigated the consequences of rising temperature on Achnatherum hymenoides, a widespread, keystone grass species on the Colorado Plateau. We tracked individual‐ and population‐level responses to identify optimal strategies that may have been masked if considering only one level of plant response.

3.We found several factors combined to affect the timing and magnitude of plant responses during the 13th year of warming. These included large warming‐induced biomass increases for individual plants, an 8.5‐day advancement in the growing season, and strong reductions in photosynthetic rates and population cover.

4.Importantly, we observed a lack of photosynthetic acclimation and, thus, a warming‐induced down regulation of photosynthetic rates. However, these physiological responses were concurrent with warmed‐plant increases in growing season length and investment in photosynthetic surfaces, demonstrating the species' ability to balance carbon fixation limitations with warming.

5.These results, which bring together ecophysiological, phenological, reproductive, and morphological assessments of plant responses to warming, suggest that the extent of change in A. hymenoides populations will be based upon numerous adaptive responses that vary in their direction and magnitude. Plant population responses to climatic warming remain poorly resolved, particularly for Earth's drylands, and our in situ experiment assessing multiple strategies offers a novel look into a warmer world.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Earlier plant growth helps compensate for reduced carbon fixation after 13 years of warming
Series title Functional Ecology
DOI 10.1111/1365-2435.13432
Volume 33
Issue 11
Year Published 2019
Language English
Publisher Wiley-Blackwell on behalf of the British Ecological Society (United Kingdom)
Contributing office(s) Southwest Biological Science Center
Description 10 p.
First page 2071
Last page 2080
Country United States
State Utah
Other Geospatial Colorado Plateau Desert