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

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 sensitivity have often emphasized abiotic factors, such as moisture limitation, while overlooking biotic vegetation structure. We tested these hypotheses using spatiotemporal models fit remote-sensing data sets assess how structure and climate influence across five dryland ecoregions western USA. Temporal was higher locations dominated by herbaceous vegetation. By contrast, much less explained mean annual PPT. In fact, ecoregion-specific showed inconsistent associations PPT; whereas decreased with increasing PPT most ecoregions, it increased arid ecoregion, hot deserts. The strong, positive on indicates that herbaceous-dominated drylands will be particularly future increases variability dramatic changes cover type caused invasions or shrub encroachment lead NPP dynamics, perhaps independent precipitation.