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Warming and free‐air CO 2 enrichment alter demographics in four co‐occurring grassland species
Author(s) -
Williams Amity L.,
Wills Karen E.,
Janes Jasmine K.,
Vander Schoor Jacqueline K.,
Newton Paul C. D.,
Hovenden Mark J.
Publication year - 2007
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2007.02170.x
Subject(s) - grassland , demographics , environmental chemistry , environmental science , chemistry , ecology , biology , demography , sociology
Summary• Species differ in their responses to global changes such as rising CO 2 and temperature, meaning that global changes are likely to change the structure of plant communities. Such alterations in community composition must be underlain by changes in the population dynamics of component species. • Here, the impact of elevated CO 2 (550 µmol mol −1 ) and warming (+2°C) on the population growth of four plant species important in Australian temperate grasslands is reported. Data collected from the Tasmanian free‐air CO 2 enrichment (TasFACE) experiment between 2003 and 2006 were analysed using population matrix models. • Population growth of Themeda triandra , a perennial C 4 grass, was largely unaffected by either factor but population growth of Austrodanthonia caespitosa , a perennial C 3 grass, was reduced substantially in elevated CO 2 plots. Warming and elevated CO 2 had antagonistic effects on population growth of two invasive weeds, Hypochaeris radicata and Leontodon taraxacoides , with warming causing population decline. Analysis of life cycle stages showed that seed production, seedling emergence and establishment were important factors in the responses of the species to global changes. • These results show that the demographic approach is very useful in understanding the variable responses of plants to global changes and in elucidating the life cycle stages that are most responsive.