Assessing the impact of large‐scale water table modifications on riparian trees: a case study from Australia. Issue 4 (1st August 2014)

• Record Type: Journal Article
• Authors: Pfautsch, Sebastian; Dodson, Wade; Madden, Sally; Adams, Mark A.
• Is Part Of: Ecohydrology. Volume 8:Issue 4(2015)
• Page Start: 642
• Page End: 651
• Publication Date: 2014-08-01
• Subjects: Ecohydrology -- Periodicals; Hydrology -- Periodicals; Water -- Environmental aspects -- Periodicals; 577.6
• DOI: 10.1002/eco.1531
• Languages: English
• ISSNs: 1936-0584

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Mining below groundwater tables is increasing globally, yet little is known of how associated large‐scale modification of water tables impact functioning of surrounding ecosystems. We used measurements of foliage density (<italic>ρ</italic><sub>F</sub>) and sapwood‐related sap flow (<italic>Q</italic><sub>S</sub>) to assess effects of depth to groundwater on <italic>Eucalyptus victrix</italic>, a tree species that is common in riparian zones in central and northern parts of Australia.</p> <p>Foliage density (<italic>ρ</italic><sub>F</sub>) varied with season and among sites. Of itself, <italic>ρ</italic><sub>F</sub> provided a partial indicator of how trees responded to falling (more than 10 m) and rising (more than 9 m) water tables. Assessment of <italic>Q</italic><sub>S</sub> was highly informative. Across all sites, <italic>Q</italic><sub>S</sub> was least (90–130 l m<sup>−2</sup> sapwood h<sup>−1</sup>) where groundwater was naturally deep (30 m) or had fallen substantially over the past 4 years (from 8 to 19 m). Fastest rates of <italic>Q</italic><sub>S</sub> (>245 l m<sup>−2</sup> sapwood h<sup>−1</sup>) were recorded where groundwater had risen to a depth similar to a site where depth to groundwater remained stable at 6–7 m. Our analyses of daytime and night‐time <italic>Q</italic><sub>S</sub> emphasize that water use by <italic>E. victrix</italic> is highly plastic and opportunistic. We discuss how empirical analysis of <italic>Q</italic><sub>S</sub>, coupled with a sound understanding of local hydrogeology, can help assess responses in ecosystem function to large‐scale modification of groundwater levels – an important issue globally, as well as in Australia. Copyright © 2014 John Wiley & Sons, Ltd.</p> </abstract>