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Biotic vs abiotic controls on temporal sensitivity of primary production to precipitation across North American drylands
Author(s) -
Felton Andrew J.,
Shriver Robert K.,
Bradford John B.,
Suding Katharine N.,
Allred Brady W.,
Adler Peter B.
Publication year - 2021
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.17543
Subject(s) - ecoregion , environmental science , vegetation (pathology) , precipitation , arid , abiotic component , spatial variability , herbaceous plant , primary production , deserts and xeric shrublands , temporal scales , ecosystem , physical geography , ecology , atmospheric sciences , geography , habitat , biology , geology , meteorology , medicine , statistics , mathematics , pathology
Summary 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.