Differential utilization of summer rains by desert plants.
Seasonal changes in the hydrogen isotope ratios of xylem waters were measured to determine water sources used for growth in desert plants of southern Utah. While all species used winter-spring recharge precipitation for spring growth, utilization of summer rains was life-form dependent. Annuals and succulent perennials exhibited a complete dependence on summer precipitation. Herbaceous and woody perennial species simultaneously utilized both summer precipitation and remaining winter-spring precipitation, with herbaceous species much more reliant on the summer precipitation component. Several of the woody perennials exhibited no response to summer precipitation. Currently, precipitation in southern Utah is evenly partitioned between winter and summer time periods; however, global circulation models predict that summer precipitation will increase in response to anticipated climate change. Our data indicate that components within the community will differentially responde to the change in precipitation patterns. These results are discussed in relation to impact on competition and possible changes in community structure.
Department of Biology, University of Utah, 84112, Salt Lake City, UT, USA.|Stable Isotope Ratio Facility for Environmental Research, University of Utah, 84112, Salt Lake City, UT, USA.
James R
JR
Ehleringer
Department of Biology, University of Utah, 84112, Salt Lake City, UT, USA.|Stable Isotope Ratio Facility for Environmental Research, University of Utah, 84112, Salt Lake City, UT, USA.
Susan L
SL
Phillips
Department of Biology, University of Utah, 84112, Salt Lake City, UT, USA.|Stable Isotope Ratio Facility for Environmental Research, University of Utah, 84112, Salt Lake City, UT, USA.
William S F
WS
Schuster
Department of Biology, University of Utah, 84112, Salt Lake City, UT, USA.|Stable Isotope Ratio Facility for Environmental Research, University of Utah, 84112, Salt Lake City, UT, USA.
Darren R
DR
Sandquist
Climate change; Desert ecology; Hydrogen isotope ratio; Water source