Biotic vs abiotic controls on temporal sensitivity of primary production to precipitation across North American drylands

New Phytologist
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Abstract

  • Dryland net primary productivity (NPP) is sensitive to temporal variation in precipitation (PPT), but the magnitude of this ‘temporal sensitivity’ varies spatially. Hypotheses for spatial variation in temporal sensitivity have often emphasized abiotic factors, such as moisture limitation, while overlooking biotic factors, such as vegetation structure.
  • We tested these hypotheses using spatiotemporal models fit to remote-sensing data sets to assess how vegetation structure and climate influence temporal sensitivity across five dryland ecoregions of the western USA.
  • Temporal sensitivity was higher in locations and ecoregions dominated by herbaceous vegetation. By contrast, much less spatial variation in temporal sensitivity was explained by mean annual PPT. In fact, ecoregion-specific models showed inconsistent associations of sensitivity and PPT; whereas sensitivity decreased with increasing mean annual PPT in most ecoregions, it increased with mean annual PPT in the most arid ecoregion, the hot deserts.
  • The strong, positive influence of herbaceous vegetation on temporal sensitivity indicates that herbaceous-dominated drylands will be particularly sensitive to future increases in precipitation variability and that dramatic changes in cover type caused by invasions or shrub encroachment will lead to changes in dryland NPP dynamics, perhaps independent of changes in precipitation.
Publication type Article
Publication Subtype Journal Article
Title Biotic vs abiotic controls on temporal sensitivity of primary production to precipitation across North American drylands
Series title New Phytologist
DOI 10.1111/nph.17543
Volume 231
Issue 6
Year Published 2021
Language English
Publisher Wiley
Contributing office(s) Southwest Biological Science Center
Description 12 p.
First page 2150
Last page 2161
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