Regional Contingencies in the Relationship between Aboveground Biomass and Litter in the World’s Grasslands

Authors

Lydia R. O’Halloran, Oregon State UniversityFollow
Elizabeth T. Borer, University of MinnesotaFollow
Eric W. Seabloom, University of MinnesotaFollow
Andrew S. MacDougall, University of Guelph
Elsa E. Cleland, University of California San DiegoFollow
Rebecca L. McCulley, University of KentuckyFollow
Sarah Hobbie, University of MinnesotaFollow
W. Stanley Harpole, Iowa State University
Nicole M. DeCrappeo, U.S. Geological Survey
Chengjin Chu, Lanzhou University
Jonathan D. Bakker, University of WashingtonFollow
Kendi F. Davies, University of Colorado at BoulderFollow
Guozhen Du, Lanzhou University
Jennifer Firn, Queensland University of Technology
Nicole Hagenah, University of KwaZulu-Natal
Kirsten S. Hofmockel, Iowa State University
Johannes Knops, University of Nebraska - LincolnFollow
Wei Li, Iowa State University
Brett A. Melbourne, University of Colorado at BoulderFollow
John W. Morgan, La Trobe University
John L. Orrock, University of Wisconsin - MadisonFollow
Suzanne M. Prober, CSIRO Ecosystem Sciences
Carly J. Stevens, Lancaster UniversityFollow

Document Type

Article

Date of this Version

2013

Citation

O’Halloran LR, Borer ET, Seabloom EW, MacDougall AS, Cleland EE, et al. (2013) Regional Contingencies in the Relationship between Aboveground Biomass and Litter in the World’s Grasslands. PLoS ONE 8(2): e54988. doi:10.1371/journal.pone.0054988

Abstract

Based on regional-scale studies, aboveground production and litter decomposition are thought to positively covary, because they are driven by shared biotic and climatic factors. Until now we have been unable to test whether production and decomposition are generally coupled across climatically dissimilar regions, because we lacked replicated data collected within a single vegetation type across multiple regions, obfuscating the drivers and generality of the association between production and decomposition. Furthermore, our understanding of the relationships between production and decomposition rests heavily on separate meta-analyses of each response, because no studies have simultaneously measured production and the accumulation or decomposition of litter using consistent methods at globally relevant scales. Here, we use a multi-country grassland dataset collected using a standardized protocol to show that live plant biomass (an estimate of aboveground net primary production) and litter disappearance (represented by mass loss of aboveground litter) do not strongly covary. Live biomass and litter disappearance varied at different spatial scales. There was substantial variation in live biomass among continents, sites and plots whereas among continent differences accounted for most of the variation in litter disappearance rates. Although there were strong associations among aboveground biomass, litter disappearance and climatic factors in some regions (e.g. U.S. Great Plains), these relationships were inconsistent within and among the regions represented by this study. These results highlight the importance of replication among regions and continents when characterizing the correlations between ecosystem processes and interpreting their global-scale implications for carbon flux. We must exercise caution in parameterizing litter decomposition and aboveground production in future regional and global carbon models as their relationship is complex.