CO₂, Nitrogen, and Diversity Differentially Affect Seed Production of Prairie Plants

Authors

J. HillieRisLambers, University of Washington
W. S. Harpole, Iowa State University
Stefan A. Schnitzer, Marquette UniversityFollow
D. Tilman, University of Minnesota - Twin Cities
P. B. Reich, University of Minnesota - Twin CitiesFollow

Document Type

Article

Language

eng

Publication Date

7-2009

Publisher

Ecological Society of America

Source Publication

Ecology

Source ISSN

0012-9658

Abstract

Plant species composition and diversity is often influenced by early life history stages; thus, global change could dramatically affect plant community structure by altering seed production. Unfortunately, plant reproductive responses to global change are rarely studied in field settings, making it difficult to assess this possibility. To address this issue, we quantified the effects of elevated CO₂, nitrogen deposition, and declining diversity on inflorescence production and inflorescence mass of 11 perennial grassland species in central Minnesota, USA. We analyzed these data to ask whether (1) global change differentially affects seed production of co‐occurring species; (2) seed production responses to global change are similar for species within the same functional group (defined by ecophysiology and growth form); and (3) seed production responses to global change match productivity responses. We found that, on average, allocation to seed production decreased under elevated CO₂, although individual species responses were rarely significant due to low power (CO₂ treatment df = 2). The effects of nitrogen deposition on seed production were similar within functional groups: C₄ grasses tended to increase while C₃ grasses tended to decrease allocation to seed production. Responses to nitrogen deposition were negatively correlated to productivity responses, suggesting a trade‐off. Allocation to seed production of some species responded to a diversity gradient, but responses were uncorrelated to productivity responses and not similar within functional groups. Presumably, species richness has complex effects on the biotic and abiotic variables that influence seed production. In total, our results suggest that seed production of co‐occurring species will be altered by global change, which may affect plant communities in unpredictable ways. Although functional groups could be used to generalize seed production responses to nitrogen deposition in Minnesota prairies, we caution against relying on them for predictive purposes without a mechanistic understanding of how resource availability and biotic interactions affect seed production.

Comments

Accepted version. Ecology, Vol. 90, No. 7 (July 2009) : 1810-1820. DOI. © 2009 Ecological Society of America. Used with permission.

Stefan Schnitzer was affiliated with University of Wisconsin, Milwaukee at the time of publication.

Recommended Citation

HillieRisLambers, J.; Harpole, W. S.; Schnitzer, Stefan A.; Tilman, D.; and Reich, P. B., "CO₂, Nitrogen, and Diversity Differentially Affect Seed Production of Prairie Plants" (2009). Biological Sciences Faculty Research and Publications. 715.
https://epublications.marquette.edu/bio_fac/715