Regional grassland productivity responses to precipitation during multiyear above- and below-average rainfall periods

TitleRegional grassland productivity responses to precipitation during multiyear above- and below-average rainfall periods
Publication TypeJournal Article
Year of Publication2018
AuthorsPetrie MD, Peters DPC, Yao J, Blair JM, Burruss ND, Collins SL, Derner JD, Gherardi LA, Hendrickson JR, Sala OE, Starks PJ, Steiner JL
JournalGlobal Change Biology
Volume24
Start Page1935
Pagination1935-1951
Date Published05/2018
Accession NumberSEV.800
Abstract

There is considerable uncertainty in the magnitude and direction of changes in precipitation
associated with climate change, and ecosystem responses are also uncertain.
Multiyear periods of above- and below-average rainfall may foretell
consequences of changes in rainfall regime. We compiled long-term aboveground
net primary productivity (ANPP) and precipitation (PPT) data for eight North American
grasslands, and quantified relationships between ANPP and PPT at each site,
and in 1–3 year periods of above- and below-average rainfall for mesic, semiarid
cool, and semiarid warm grassland types. Our objective was to improve understanding
of ANPP dynamics associated with changing climatic conditions by contrasting
PPT–ANPP relationships in above- and below-average PPT years to those that
occurred during sequences of multiple above- and below-average years. We found
differences in PPT–ANPP relationships in above- and below-average years compared
to long-term site averages, and variation in ANPP not explained by PPT totals that
likely are attributed to legacy effects. The correlation between ANPP and currentand
prior-year conditions changed from year to year throughout multiyear periods,
with some legacy effects declining, and new responses emerging. Thus, ANPP in a
given year was influenced by sequences of conditions that varied across grassland
types and climates. Most importantly, the influence of prior-year ANPP often
increased with the length of multiyear periods, whereas the influence of the amount
of current-year PPT declined. Although the mechanisms by which a directional
change in the frequency of above- and below-average years imposes a persistent
change in grassland ANPP require further investigation, our results emphasize the
importance of legacy effects on productivity for sequences of above- vs. belowaverage
years, and illustrate the utility of long-term data to examine these patterns.

DOI10.1111/gcb.14024