Hydraulic redistribution (HR) is a common phenomenon in water-limited ecosystems; however, it remains unclear how the volume of water transported via HR compares to other components of the hydrologic budget and how HR influences water availability for understory plant communities. In this study, we investigate the absolute and relative magnitude of HR on a forest water budget and identify potential impacts of this water subsidy to understory plant communities. We scaled tree-level estimates of transpiration and HR of three common tree species naturally occurring in a longleaf pine woodland with plot-level measurements of basal area to determine their magnitude at the stand scale. We trenched plots containing understory vegetation but devoid of mature trees and their connected roots to exclude HR subsidies to understory plant species. We analysed soil water isotopes and assessed leaf water potential (Psi(L)) in trenched and control plots to determine if HR results in mixing of water among soil strata and improves understory plant moisture status. Water inputs from HR were equivalent to >30% of total rainfall for the site during the observation period and similar to 40% of total tree water uptake, depending on species. A stable isotope mixing model confirmed that soil water within HR-exposed plots was more similar to groundwater, whereas soil water within trenched plots was more similar to precipitation. Exclusion of HR via trenching decreased soil moisture and pre-dawn Psi(L) for all understory species. These three lines of evidence suggest that HR from overstory trees redistributes a sizable portion of water from deeper to shallower soil profiles and that this water subsidy enhances understory plant water status.
机构:
Joseph W Jones Ecol Res Ctr, Newton, GA 39870 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Kirkman, L. Katherine
;
Smith, Lora L.
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Joseph W Jones Ecol Res Ctr, Newton, GA 39870 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Smith, Lora L.
;
Quintana-Ascencio, Pedro F.
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Univ Cent Florida, Dept Biol, Orlando, FL 32816 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Quintana-Ascencio, Pedro F.
;
Kaeser, Melanie J.
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Joseph W Jones Ecol Res Ctr, Newton, GA 39870 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Kaeser, Melanie J.
;
Golladay, Stephen W.
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Joseph W Jones Ecol Res Ctr, Newton, GA 39870 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Golladay, Stephen W.
;
Farmer, Anna L.
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机构:
Joseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Florida Fish & Wildlife Conservat Commiss, Lake City, FL 32055 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
机构:
Univ Alaska Anchorage, Dept Biol Sci, Anchorage, AK 99508 USAUniv Alaska Anchorage, Dept Biol Sci, Anchorage, AK 99508 USA
Kulmatiski, Andrew
;
Beard, Karen H.
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机构:
Utah State Univ, Dept Wildland Resources, Logan, UT 84322 USA
Utah State Univ, Ctr Ecol, Logan, UT 84322 USAUniv Alaska Anchorage, Dept Biol Sci, Anchorage, AK 99508 USA
机构:
Joseph W Jones Ecol Res Ctr, Newton, GA 39870 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Kirkman, L. Katherine
;
Smith, Lora L.
论文数: 0引用数: 0
h-index: 0
机构:
Joseph W Jones Ecol Res Ctr, Newton, GA 39870 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Smith, Lora L.
;
Quintana-Ascencio, Pedro F.
论文数: 0引用数: 0
h-index: 0
机构:
Univ Cent Florida, Dept Biol, Orlando, FL 32816 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Quintana-Ascencio, Pedro F.
;
Kaeser, Melanie J.
论文数: 0引用数: 0
h-index: 0
机构:
Joseph W Jones Ecol Res Ctr, Newton, GA 39870 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Kaeser, Melanie J.
;
Golladay, Stephen W.
论文数: 0引用数: 0
h-index: 0
机构:
Joseph W Jones Ecol Res Ctr, Newton, GA 39870 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Golladay, Stephen W.
;
Farmer, Anna L.
论文数: 0引用数: 0
h-index: 0
机构:
Joseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
Florida Fish & Wildlife Conservat Commiss, Lake City, FL 32055 USAJoseph W Jones Ecol Res Ctr, Newton, GA 39870 USA
机构:
Univ Alaska Anchorage, Dept Biol Sci, Anchorage, AK 99508 USAUniv Alaska Anchorage, Dept Biol Sci, Anchorage, AK 99508 USA
Kulmatiski, Andrew
;
Beard, Karen H.
论文数: 0引用数: 0
h-index: 0
机构:
Utah State Univ, Dept Wildland Resources, Logan, UT 84322 USA
Utah State Univ, Ctr Ecol, Logan, UT 84322 USAUniv Alaska Anchorage, Dept Biol Sci, Anchorage, AK 99508 USA