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Influence of warming on soil water potential controls seedling mortality in perennial but not annual species in a temperate grassland
Author(s) -
Hovenden Mark J.,
Newton Paul C. D.,
Wills Karen E.,
Janes Jasmine K.,
Williams Amity L.,
Vander Schoor Jacqueline K.,
Nolan Michaela J.
Publication year - 2008
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.1469-8137.2008.02563.x
Subject(s) - seedling , perennial plant , grassland , survivorship curve , agronomy , temperate climate , biology , transpiration , environmental science , ecology , botany , photosynthesis , genetics , cancer
Summary• In a water‐limited system, the following hypotheses are proposed: warming will increase seedling mortality; elevated atmospheric CO 2 will reduce seedling mortality by reducing transpiration, thereby increasing soil water availability; and longevity (i.e. whether a species is annual or perennial) will affect the response of a species to global changes. • Here, these three hypotheses are tested by assessing the impact of elevated CO 2 (550 µmol mol −1 ) and warming (+2°C) on seedling emergence, survivorship and establishment in an Australian temperate grassland from autumn 2004 to autumn 2007. • Warming impacts on seedling survivorship were dependent upon species longevity. Warming reduced seedling survivorship of perennials through its effects on soil water potential but the seedling survivorship of annuals was reduced to a greater extent than could be accounted for by treatment effects on soil water potential. Elevated CO 2 did not significantly affect seedling survivorship in annuals or perennials. • These results show that warming will alter recruitment of perennial species by changing soil water potential but will reduce recruitment of annual species independent of any effects on soil moisture. The results also show that exposure to elevated CO 2 does not make seedlings more resistant to dry soils.