caa a22 4500 467885605 CHVBK 20180406152733.0 cr unu---uuuuu 170328e20060401xx s 000 0 eng 10.1007/s10021-005-0161-z doi (NATIONALLICENCE)springer-10.1007/s10021-005-0161-z The Spatial Structure of Variability in a Semi-arid, Fluvial Ecosystem [Elektronische Daten] [David Lewis, John Schade, Anne Huth, Nancy Grimm] The arrangement and composition of flowpath types within a given network are thought to govern its functioning. This concept assumes that different flowpath types are functionally distinct. We investigated this assumption in a fluvial ecosystem by comparing the riparian zone, parafluvial zone (in-channel gravel bars), and surface stream. We hypothesized that differences in advection, uptake, and sorption would render material cycles more (a) open and (b) mutable in the surface stream, whereas the converse would occur in the riparian zone, and an intermediate state would be seen in the intervening parafluvial zone. To test our first hypothesis, we predicted that spatial heterogeneity in solute concentrations would be least in the surface stream, greater in the parafluvial zone, and greatest in the riparian zone. Using a null model, we ascertained that this pattern was shown by all solute species we examined (nitrate, ammonium, total dissolved inorganic nitrogen [DIN], dissolved organic N, total dissolved N, soluble reactive phosphorus, dissolved organic carbon, and chloride). To test our second hypothesis, we predicted that temporal change in spatial heterogeneity would be greatest in the surface stream, less in the parafluvial zone, and least in the riparian zone. Nitrate, DIN, and chloride showed this pattern. In particular, surface stream inorganic N was less spatially variable following months of high rainfall. According to an extant hypothesis, these results suggest that inorganic N processing may be a stable function in this ecosystem. Other solute species did not support our second prediction, perhaps because their retention and release dynamics are influenced principally by geochemistry. Generally, our findings indicate that a geomorphic template can generate spatial patterns in ecosystem function, warranting an expansion of the spiraling framework to a variety of flowpath types. Springer Science+Business Media, Inc., 2006 Arizona nationallicence ecosystem function nationallicence geomorphic template nationallicence null model nationallicence process nationallicence parafluvial zone nationallicence process nationallicence San Pedro River nationallicence riparian zone nationallicence stability nationallicence Lewis David School of Life Sciences, Arizona State University, P.O. Box 873211, 85287, Tempe, Arizona, USA aut Schade John School of Life Sciences, Arizona State University, P.O. Box 873211, 85287, Tempe, Arizona, USA aut Huth Anne Department of Hydrology and Water Resources, University of Arizona, 85721, Tucson, Arizona, USA aut Grimm Nancy School of Life Sciences, Arizona State University, P.O. Box 873211, 85287, Tempe, Arizona, USA aut Ecosystems Springer-Verlag; www.springer-ny.com 9/3(2006-04-01), 386-397 1432-9840 9:3<386 2006 9 10021 https://doi.org/10.1007/s10021-005-0161-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-005-0161-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lewis David School of Life Sciences, Arizona State University, P.O. Box 873211, 85287, Tempe, Arizona, USA aut NATIONALLICENCE 700 1- Schade John School of Life Sciences, Arizona State University, P.O. Box 873211, 85287, Tempe, Arizona, USA aut NATIONALLICENCE 700 1- Huth Anne Department of Hydrology and Water Resources, University of Arizona, 85721, Tucson, Arizona, USA aut NATIONALLICENCE 700 1- Grimm Nancy School of Life Sciences, Arizona State University, P.O. Box 873211, 85287, Tempe, Arizona, USA aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag; www.springer-ny.com 9/3(2006-04-01), 386-397 1432-9840 9:3<386 2006 9 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer