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Temporal dynamics of fine roots under long‐term exposure to elevated CO 2 in the Mojave Desert
Author(s) -
Sonderegger Derek L.,
Ogle Kiona,
Evans R. Dave,
Ferguson Scot,
Nowak Robert S.
Publication year - 2013
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/nph.12128
Subject(s) - environmental science , ecosystem , biomass (ecology) , phenology , soil water , antecedent moisture , agronomy , terrestrial ecosystem , ecology , atmospheric sciences , biology , soil science , runoff curve number , surface runoff , geology
Summary Deserts are considered 'below‐ground dominated', yet little is known about the impact of rising CO 2 in combination with natural weather cycles on long‐term dynamics of root biomass. This study quantifies the temporal dynamics of fine‐root production, loss and standing crop in an intact desert ecosystem exposed to 10 yr of elevated CO 2 . We used monthly minirhizotron observations from 4 yr (2003–2007) for two dominant shrub species and along community transects at the Nevada Desert free‐air CO 2 enrichment Facility. Data were synthesized within a Bayesian framework that included effects of CO 2 concentration, cover type, phenological period, antecedent soil water and biological inertia (i.e. the influence of prior root production and loss). Elevated CO 2 treatment interacted with antecedent soil moisture and had significantly greater effects on fine‐root dynamics during certain phenological periods. With respect to biological inertia, plants under elevated CO 2 tended to initiate fine‐root growth sooner and sustain growth longer, with the net effect of increasing the magnitude of production and mortality cycles. Elevated CO 2 interacts with past environmental (e.g. antecedent soil water) and biological (e.g. biological inertia) factors to affect fine‐root dynamics, and such interactions are expected to be important for predicting future soil carbon pools.