A Multiscale, Hierarchical Model of Pulse Dynamics in Arid-Land Ecosystems

Ecological processes in arid lands are often described by the pulse-reserve paradigm, in which rain events drive biological activity until moisture is depleted, leaving a reserve. This paradigm is frequently applied to processes stimulated by one or a fewprecipitation eventswithin a growing season.Here we expand the original framework in time and space and include other pulses that interact with rainfall. This new hierarchical pulse-dynamics framework integrates space and time throughpulse-driven exchanges, interactions, transitions, and transfers that occur across individual tomultiple pulses extending frommicro to watershed scales. Climate change will likely alter the size, frequency, and intensity of precipitation pulses in the future, and arid-land ecosystems are known to be highly sensitive to climate variability. Thus, a more comprehensive understanding of arid-land pulse dynamics is needed to determine how these ecosystemswill respond to, and be shaped by, increased climate variability. 397 A nn u. R ev . E co l. E vo l. Sy st . 2 01 4. 45 :3 97 -4 19 . D ow nl oa de d fr om w w w .a nn ua lr ev ie w s. or g A cc es s pr ov id ed b y U ni ve rs ity o f N ew M ex ic o (U N M ) on 1 2/ 10 /1 4. F or p er so na l u se o nl y. ES45CH18-Collins ARI 15 October 2014 11:49