Oecologia (2004) 138: 341–349 DOI 10.1007/s00442-003-1460-8 ECOPHYSIOLOGY J. F. Espeleta . J. B. West . L. A. Donovan Species-specific patterns of hydraulic lift in co-occurring adult trees and grasses in a sandhill community Received: 24 March 2003 / Accepted: 13 November 2003 / Published online: 19 December 2003 # Springer-Verlag 2003 Abstract Plants can significantly affect ecosystem water balance by hydraulic redistribution (HR) from dry to wet soil layers via roots (also called hydraulic lift, HL, when the redistribution is from deep to shallow soil). However, the information on how co-occurring species in natural habitats differ in HL ability is insufficient. In a field study, we compared HL ability of four tree species (including three congeneric oak species) and two C4 bunch grass species that co-occur in subxeric habitats of fall-line sandhills in southeastern USA. Soil water potentials (ψ s ) were recorded hourly for 3 years both in large chambers that isolated roots for each species and outside the chambers. Outside of root chambers, soil drying occurred periodically in the top 25 cm and corresponded with lack of precipitation during the summer growing season. Soil moisture was continuously available at a 1 m depth. HL activity was observed in three of the tree species, with greater frequency for Pinus palustris than for Quercus laevis and Q. incana. The fourth tree species Q. margaretta did not exhibit HL activity even though it experienced a similar ψ s gradient. For the C4 bunch grasses, Aristida stricta exhibited a small amount of HL activity, but Schizachyrium scoparium did not. The capacity for HL activity may be linked to the species ecological distribution. The four species that exhibited HL activity in this subxeric habitat are also dominant in adjacent xeric sandhill habitats, whereas the species that did not exhibit HL are scarcely found in the xeric areas. This is consistent with other studies that found greater fine root survival in dry soil for the four xeric species exhibiting HL activity. The differential ability of these species to redistribute water from the deep soil to the rapidly drying shallow soil likely has a strong effect on the water balance of sandhill plant communities, and is likely linked to their differential distribution across edaphic gradients. Keywords Aristida stricta . Hydraulic lift . Hydraulic redistribution . Pinus palustris . Quercus laevis Introduction The patterns of use and redistribution of soil water by plant species have considerable impact on the hydrological cycles of terrestrial ecosystems (Jackson et al. 2000a). For example, species from a single community may differ substantially in rooting depth and water consumption so that shifts in species composition can significantly alter patterns of ecosystem water use (Jackson et al. 2000a). Another way that plants can affect hydrology is via “hydraulic redistribution” (HR), defined as the nighttime transfer of water from wet to dry soil via plant roots (Caldwell et al. 1998). HR is more specifically called “hydraulic lift” for the transfer of deep soil water to dry surface soil (Richards and Caldwell 1987) or “reverse hydraulic lift” for the downward transport of water when an opposite pattern is present in the soil moisture profile (Burgess et al. 1998; Schulze et al. 1998; Smith et al. 1999). HR can alter the water balances of single plants, stands of single species, and entire forests and regions (Williams et al. 1993; Emerman and Dawson 1996; Burgess et al. 1998; Caldwell et al. 1998; Jackson et al. 2000b; Brooks et al. 2002; Ryel et al. 2002). For example, in a sugar maple (Acer saccharum) forest with root access J. F. Espeleta (*) . J. B. West . L. A. Donovan Department of Plant Biology, University of Georgia, Athens, GA 30602, USA Tel.: +1-506-7666565 Fax: +1-506-7666535 J. F. Espeleta La Selva Biological Station, Organization for Tropical Studies, Puerto Viejo de Sarapiquí, Costa Rica J. B. West Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108, USA Present address: J. F. Espeleta Organization for Tropical Studies Interlink 341, P.O. Box 02–5635 Miami, FL 33102, USA