Water sources and nitrogen relations of grasses and shrubs in phreatophytic communities of the Great Basin Desert

Pataki, Diane E.; Billings, Sharon A.; Naumburg, Elke; Goedhart, Christine M.

doi:10.1016/j.jaridenv.2008.03.011

Cited by 31 publications

(40 citation statements)

References 55 publications

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“…These results indicate that in sites where groundwater is accessible, N serves as a strong control on the photosynthetic activity of D. spicata during the summer. The grassland site had more soil organic N than either the intermediate or shrubland sites (Pataki et al 2008) and more KCl extractable soil inorganic N than the shrubland site (Fig. 1a).…”

Section: Discussionmentioning

confidence: 94%

“…Shallow soil moisture affects nitrogen mineralization rates, and soil texture is an important control on soil water holding ability and evaporation. The grassland and intermediate site soils are composed predominately of silt, while the shrubland soil texture is sandy (Pataki et al 2008). The larger spaces between sand particles inhibit capillary movement of groundwater, contributing to differences in both soil moisture and soil water isotopic values with depth.…”

Section: Discussionmentioning

confidence: 99%

“…In that study, grasses exhibited similar leaf N concentrations and isotopic composition as glycophytic shrubs, but halophytic shrubs showed higher concentrations of leaf N. In particular, the halophytic shrub Atriplex torreyi showed high concentrations of leaf N that were isotopically enriched relative to other species. Isotopically enriched leaf N corresponded to isotopically enriched soil N in the shallow surface soil associated with high rates of gaseous N losses (Pataki et al 2008). Atriplex torreyi appears to have a competitive advantage in N uptake in the saline upper soil layers -where N availability is generally higher than deeper in the soil profile -that may influence its patterns of growth and distribution.…”

Section: Introductionmentioning

confidence: 90%

“…Detailed site descriptions are given in Pataki et al (2008). Briefly, the grassland site had an average DTW of 1.5-2 m throughout the 2006 sampling period, and was composed predominantly of grass species, including Distichlis spicata, Sporobolus airoides, and Leymus triticoides.…”

Section: Study Sitesmentioning

confidence: 99%

“…We have shown previously that grasses in the central Owens Valley near Bishop, CA utilize shallow, isotopically enriched sources of water, unlike neighboring shrubs which appear to rely on groundwater when water tables are within 3 m of the surface (Pataki et al 2008). In that study, grasses exhibited similar leaf N concentrations and isotopic composition as glycophytic shrubs, but halophytic shrubs showed higher concentrations of leaf N. In particular, the halophytic shrub Atriplex torreyi showed high concentrations of leaf N that were isotopically enriched relative to other species.…”

Section: Introductionmentioning

confidence: 98%

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Seasonal variations in plant nitrogen relations and photosynthesis along a grassland to shrubland gradient in Owens Valley, California

2009

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Community composition in semi-arid ecosystems has largely been explained by water availability; however, nitrogen is a common limiting nutrient, and may be an important control on plant function and carbon uptake. We investigated nitrogen relations and photosynthesis of several dominant species at shallow groundwater sites in Owens Valley, California. We measured soil nitrogen (N) availability, leaf N and isotopes, water isotopes, and gas exchange of dominant shrub species Atriplex torreyi and Ericameria nauseosa and grass species Distichlis spicata throughout the summer season in three sites that had similar watertable depths, but that varied in community composition and N availability. Surface soil inorganic N was greatest at the grassland site and declined from June to September at all sites. Leaf N declined throughout the season in all species, and was correlated with soil inorganic N. Photosynthesis of A. torreyi remained relatively constant throughout the season. In contrast, D. spicata and E. nauseosa experienced seasonal declines in photosynthesis at sites with greater inorganic N availability. Leaf N was significantly correlated with photosynthesis in D. spicata across all sites and measurement periods. Controls on N cycling are likely to be an important determinant of photosynthesis of D. spicata in this region.

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 90%

Section: Study Sitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 3 more Smart Citations

Seasonal variations in plant nitrogen relations and photosynthesis along a grassland to shrubland gradient in Owens Valley, California

2009

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Ecosystem effects of groundwater depth in Owens Valley, California

Goedhart

Pataki

2011

Ecohydrology

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Owens Valley, California, USA, is an important source of water for the city of Los Angeles; however, recent studies have documented losses of grass cover coinciding with decreased watertable depths in many locations. These changes in community composition are assumed to be associated with shallower rooting depths and greater vulnerability to declining watertable depths in grasses compared to neighbouring shrubs. However, the hydraulic properties and water stress resistance of most species in Owens Valley have not been measured. In addition, the relationships between groundwater depth and other aspects of ecosystem function such as nutrient cycling are not well understood. In this study, we measured grass and shrub cover, vulnerability to cavitation, and plant and soil isotopic and chemical composition at 9 sites along a depth to watertable gradient of 0Ð3-5Ð7 m in Owens Valley. Contrary to expectations, the grass species was more resistant to water stress-induced cavitation than either shrub species. However, grass cover declined in sites with deeper watertables while shrub cover remained constant. Water isotopes indicated shallower rooting depths in grasses than in shrubs, although the phreatophytic shrub Ericameria nauseosa had enriched leaf water isotopes at deep groundwater sites, indicating water stress. Sites with lower grass cover contained less soil nitrogen (N) that was also more isotopically enriched, which is indicative of greater ecosystem N losses. These results show that groundwater depth is correlated with a number of ecosystem traits in these Great Basin Desert ecosystems and should be considered when evaluating future changes in groundwater depth.

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Flood water legacy as a persistent source for riparian vegetation during prolonged drought: an isotopic study of Arundo donax on the Rio Grande

Moore

et al. 2015

Ecohydrology

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Invasive riparian plants along arid and semi-arid rivers are thought to accelerate stream flow recession rates during drought. However, the fraction of river water used directly by plants is unknown. Riparian water sources for plants may also include shallow groundwater, which may differ from the river itself, or water from the unsaturated zone originating from localized rain events or prior floods. Floods that saturate the soil may persist as a lasting legacy to sustain plants over longer time scales. In this study, we examined potential sources of water used by Giant Reed (Arundo donax L.) following a flood and subsequent prolonged drought using natural-abundance stable isotopes of oxygen (δ 18 O) and hydrogen (δ 2 H). River and rain water, groundwater, soil, and rhizome samples were collected along four approximately 100-m transects perpendicular to the Rio Grande River in southwest Texas. Our observations coincided with a major flood that saturated soils in July of 2010 followed by extreme drought through fall of 2011. Our results showed that the isotope ratio of rhizome water was consistent with prolonged utilization of flood water, which persisted within flood-recharged surface soils throughout the following summer. Apparently, groundwater was not the dominant source for A. donax when soil moisture was sufficient for plant uptake following a flood. While hydrogeology of rivers vary, this finding highlights the potential for floodwater to sustain riparian vegetation for prolonged periods without rainfall and demonstrates that this may be an important alternative source of water that is not currently accounted for in hydrologic models.

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Water sources and nitrogen relations of grasses and shrubs in phreatophytic communities of the Great Basin Desert

Cited by 31 publications

References 55 publications

Seasonal variations in plant nitrogen relations and photosynthesis along a grassland to shrubland gradient in Owens Valley, California

Seasonal variations in plant nitrogen relations and photosynthesis along a grassland to shrubland gradient in Owens Valley, California

Ecosystem effects of groundwater depth in Owens Valley, California

Flood water legacy as a persistent source for riparian vegetation during prolonged drought: an isotopic study of Arundo donax on the Rio Grande

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