ibclogo XVI International Botanical Congess


Abstract Number: 4246
Session = 5.3.3


C3/C4 PLANTS AND CLIMATE-PAST, PRESENT, AND FUTURE.


James Ehleringer & Thure Cerling, University of Utah, Salt Lake City


There is strong ecological, geographical, and palaeoecological evidence that abundances and distributions of plants possessing C4 photosynthesis are related to climate, particularly to both atmospheric carbon dioxide and temperature. We examine a model to explain C3/C4 distributions globally over time. This model predicts (a) the emergence of C4 plants in the late Miocene, in response to decreasing carbon dioxide levels, (b) the expansion of C4-dominated ecosystems in glacial periods, especially in tropical and subtropical regions, and (c) the decline in C4 abundance in response to current and projected atmospheric carbon dioxide levels. Understanding the distributions of C3/C4 plants impacts not only primary productivity and terrestrial carbon balance, but also the distribution and evolution of animals.


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