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Long‐term response of a Mojave Desert winter annual plant community to a whole‐ecosystem atmospheric CO 2 manipulation ( FACE )
Author(s) -
Smith Stanley D.,
Charlet Therese N.,
Zitzer Stephen F.,
Abella Scott R.,
Vanier Cheryl H.,
Huxman Travis E.
Publication year - 2014
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.12411
Subject(s) - bromus , forb , phenology , annual plant , ecosystem , dominance (genetics) , productivity , plant community , arid , ecology , climate change , environmental science , biology , agronomy , grassland , ecological succession , poaceae , biochemistry , macroeconomics , economics , gene
Desert annuals are a critically important component of desert communities and may be particularly responsive to increasing atmospheric ( CO 2 ) because of their high potential growth rates and flexible phenology. During the 10‐year life of the Nevada Desert FACE (free‐air CO 2 enrichment) Facility, we evaluated the productivity, reproductive allocation, and community structure of annuals in response to long‐term elevated ( CO 2 ) exposure. The dominant forb and grass species exhibited accelerated phenology, increased size, and higher reproduction at elevated ( CO 2 ) in a wet El Niño year near the beginning of the experiment. However, a multiyear dry cycle resulted in no increases in productivity or reproductive allocation for the remainder of the experiment. At the community level, early indications of increased dominance of the invasive Bromus rubens at elevated ( CO 2 ) gave way to an absence of Bromus in the community during a drought cycle, with a resurgence late in the experiment in response to higher rainfall and a corresponding high density of Bromus in a final soil seed bank analysis, particularly at elevated ( CO 2 ). This long‐term experiment resulted in two primary conclusions: (i) elevated ( CO 2 ) does not increase productivity of annuals in most years; and (ii) relative stimulation of invasive grasses will likely depend on future precipitation, with a wetter climate favoring invasive grasses but currently predicted greater aridity favoring native dicots.