Channel incision and patterns of cottonwood stress and mortality along the Mojave River, California

Scott, Michael L.; Lines, Gregory C.; Auble, Gregor T.

doi:10.1006/jare.1999.0614

Cited by 76 publications

(62 citation statements)

References 12 publications

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“…The composition of riparian vegetation, in turn, is strongly influenced by hydrology; particularly flood regime and groundwater levels. Changes in flood regime affect seedling establishment, channel incision, sediment transport and depth to water table (Shafroth et al 1998;Bendix & Hupp 2000;Scott et al 2000). Although these interactions are not typically cast in terms of nonlinear dynamics, positive feedbacks and biological thresholds are likely to exist.…”

Section: Nonlinear Dynamics In Riversmentioning

confidence: 99%

Multiple states in river and lake ecosystems

Dent

Cumming

Carpenter

2002

Phil. Trans. R. Soc. Lond. B

137

116

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Nonlinear models of ecosystem dynamics that incorporate positive feedbacks and multiple, internally reinforced states have considerable explanatory power. However, linear models may be adequate, particularly if ecosystem behaviour is primarily controlled by external processes. In lake ecosystems, internal (mainly biotic) processes are thought to have major impacts on system behaviour, whereas in rivers, external (mainly physical) factors have traditionally been emphasized. We consider the hypothesis that models that exhibit multiple states are useful for understanding the behaviour of lake ecosystems, but not as useful for understanding stream ecosystems. Some of the best-known examples of multiple states come from lake ecosystems. We review some of these examples, and we also describe examples of multiple states in rivers. We conclude that the hypothesis is an oversimplification; the importance of physical forcing in rivers does not eliminate the possibility of internal feedbacks that create multiple states, although in rivers these feedbacks are likely to include physical as well as biotic processes. Nonlinear behaviour in aquatic ecosystems may be more common than current theory indicates.

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Section: Nonlinear Dynamics In Riversmentioning

confidence: 99%

Multiple states in river and lake ecosystems

Dent

Cumming

Carpenter

2002

Phil. Trans. R. Soc. Lond. B

137

116

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“…The susceptibility of riparian forests to changes in the availability of water within terrestrial storage reservoirs (i.e. vadose and phreatic zones) is well appreciated (Dufour and Piégay, 2008;Scott et al, 2000;Singer et al, 2013). Yet there is a lack of information regarding the seasonal progression of water partitioning within these floodplain reservoirs and its uptake by trees.…”

Section: Introductionmentioning

confidence: 99%

“…Populus spp, with growth retardation and mortality commonly observed, as a result of reduced streamflow and/or hydraulic connectivity with the channel, which leads to a decline in phreatic water availability (Amlin and Rood, 2002;Lambs et al, 2006;Rood et al, 2003;Scott et al, 2000;Smith et al, 1991;Stromberg and Patten, 1996). For shallowly rooted species such as Fraxinus spp, moisture uptake is limited to the vadose zone because of mechanical impedance of root growth by gravelly substrates, the elevation of which is regarded as the upper limit of the phreatic zone .…”

mentioning

confidence: 99%

Sub‐annual variability in historical water source use by Mediterranean riparian trees

Sargeant

Singer

2016

Ecohydrology

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The seasonal availability of water within a tree's rooting zone may be an important determinant for individual tree growth and overall forest health, particularly in riparian corridors of Mediterranean climate zones that are vulnerable to water stress. Here, we present a new method that combines dendro-isotopes and isotope modelling for determining how water source use varies over 10 consecutive growing seasons (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010) for co-occurring species Populus nigra and Fraxinus excelsior, along the Rhône River, south-eastern France. We conducted highly resolved δ 18 O analysis of cellulose micro-slices within tree-rings and back-calculated the δ 18 O signature of source water available at the time of growth using a biochemical fractionation model. We related these patterns to inferred seasonal hydrological partitioning through comparison with δ 18 O of waters from the vadose and phreatic zones, precipitation and streamflow. The shallowly rooted Fraxinus displayed greater sub-annual source water variability, as well as greater isotopic enrichment, reflecting use of precipitation-derived vadose moisture. Its earlywood was formed mainly from winter rainfall (δ 18 O depleted) whilst the latewood was composed from growing season precipitation (δ 18 O enriched). In Populus, the sub-annual source water use was relatively depleted, suggesting use of hyporheic water and regional groundwater. From 2007, both species converged in their pattern of water source uptake which was attributed to a decline in phreatic water access for Populus. These results demonstrate that the seasonal variability in source water use can be identified retrospectively, a method which may prove important for anticipating the future consequences of climate-driven changes to the hydrological cycle.

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“…Use of groundwater by phreatophytes is highest during the driest season of the year when alternative water sources become depleted and transpirational demand is highest. It is also suggested that phreatophytes are susceptible to the rate as well as season of drawdown (Mahoney and Rood 1992;Stromberg and Patten 1992;Tyree et al 1994;Scott et al 1999Scott et al , 2000Groom et al 2000;Shatfroth et al 2000;Horton et al 2001;Eamus et al 2006a) by having a higher rate of water-table decline than fine-root elongation rate, and/or lowering the water table during a time other than the root growth season (Sorenson et al 1991). Low magnitude and rates of change in groundwater levels as opposed to rapid drawdown, may allow intra-and inter-generational adaptation and persistence of phreatophytes (Scott et al 1999;Shatfroth et al 2000).…”

Section: Groundwater-dependent Ecosystem Management: Current Issuesmentioning

confidence: 99%