Diverse Responses of Phenology to Global Changes in a Grassland Ecosystem
Shifting plant phenology (i.e., timing of flowering and other developmental events) in recent decades establishes that species and ecosystems are already responding to global environmental change. Earlier flowering and an extended period of active plant growth across much of the northern hemisphere...
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Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 103; no. 37; pp. 13740 - 13744 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
National Academy of Sciences
12.09.2006
National Acad Sciences |
Subjects | |
Online Access | Get full text |
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Summary: | Shifting plant phenology (i.e., timing of flowering and other developmental events) in recent decades establishes that species and ecosystems are already responding to global environmental change. Earlier flowering and an extended period of active plant growth across much of the northern hemisphere have been interpreted as responses to warming. However, several kinds of environmental change have the potential to influence the phenology of flowering and primary production. Here, we report shifts in phenology of flowering and canopy greenness (Normalized Difference Vegetation Index) in response to four experimentally simulated global changes: warming, elevated CO₂, nitrogen (N) deposition, and increased precipitation. Consistent with previous observations, warming accelerated both flowering and greening of the canopy, but phenological responses to the other global change treatments were diverse. Elevated CO₂ and N addition delayed flowering in grasses, but slightly accelerated flowering in forbs. The opposing responses of these two important functional groups decreased their phenological complementarity and potentially increased competition for limiting soil resources. At the ecosystem level, timing of canopy greenness mirrored the flowering phenology of the grasses, which dominate primary production in this system. Elevated CO₂ delayed greening, whereas N addition dampened the acceleration of greening caused by warming. Increased precipitation had no consistent impacts on phenology. This diversity of phenological changes, between plant functional groups and in response to multiple environmental changes, helps explain the diversity in large-scale observations and indicates that changing temperature is only one of several factors reshaping the seasonality of ecosystem processes. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Edited by Margaret B. Davis, University of Minnesota, St. Paul, MN, and approved July 5, 2006 Present address: Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708. Author contributions: E.E.C., N.R.C., H.A.M., and C.B.F. designed research; E.E.C., N.R.C., and S.R.L. performed research; E.E.C. and N.R.C. analyzed data; and E.E.C. and C.B.F. wrote the paper. |
ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.0600815103 |