| Title |
Natural abundance (δ15N) indicates shifts in nitrogen relations of woody taxa along a savanna–woodland continental rainfall gradient
|
|---|---|
| Published in |
Oecologia, December 2014
|
| DOI | 10.1007/s00442-014-3176-3 |
| Pubmed ID | |
| Authors |
Fiona M. Soper, Anna E. Richards, Ilyas Siddique, Marcos P. M. Aidar, Garry D. Cook, Lindsay B. Hutley, Nicole Robinson, Susanne Schmidt |
| Abstract |
Water and nitrogen (N) interact to influence soil N cycling and plant N acquisition. We studied indices of soil N availability and acquisition by woody plant taxa with distinct nutritional specialisations along a north Australian rainfall gradient from monsoonal savanna (1,600-1,300 mm annual rainfall) to semi-arid woodland (600-250 mm). Aridity resulted in increased 'openness' of N cycling, indicated by increasing δ(15)Nsoil and nitrate:ammonium ratios, as plant communities transitioned from N to water limitation. In this context, we tested the hypothesis that δ(15)Nroot xylem sap provides a more direct measure of plant N acquisition than δ(15)Nfoliage. We found highly variable offsets between δ(15)Nfoliage and δ(15)Nroot xylem sap, both between taxa at a single site (1.3-3.4 ‰) and within taxa across sites (0.8-3.4 ‰). As a result, δ(15)Nfoliage overlapped between N-fixing Acacia and non-fixing Eucalyptus/Corymbia and could not be used to reliably identify biological N fixation (BNF). However, Acacia δ(15)Nroot xylem sap indicated a decline in BNF with aridity corroborated by absence of root nodules and increasing xylem sap nitrate concentrations and consistent with shifting resource limitation. Acacia dominance at arid sites may be attributed to flexibility in N acquisition rather than BNF capacity. δ(15)Nroot xylem sap showed no evidence of shifting N acquisition in non-mycorrhizal Hakea/Grevillea and indicated only minor shifts in Eucalyptus/Corymbia consistent with enrichment of δ(15)Nsoil and/or decreasing mycorrhizal colonisation with aridity. We propose that δ(15)Nroot xylem sap is a more direct indicator of N source than δ(15)Nfoliage, with calibration required before it could be applied to quantify BNF. |
X Demographics
The data shown below were collected from the profiles of 3 X users who shared this research output. Click here to find out more about how the information was compiled.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Canada | 1 | 33% |
| United States | 1 | 33% |
| Unknown | 1 | 33% |
Demographic breakdown
| Type | Count | As % |
|---|---|---|
| Scientists | 2 | 67% |
| Members of the public | 1 | 33% |
Mendeley readers
The data shown below were compiled from readership statistics for 52 Mendeley readers of this research output. Click here to see the associated Mendeley record.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Mexico | 1 | 2% |
| Hungary | 1 | 2% |
| South Africa | 1 | 2% |
| Unknown | 49 | 94% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Student > Ph. D. Student | 10 | 19% |
| Researcher | 9 | 17% |
| Student > Master | 8 | 15% |
| Student > Bachelor | 4 | 8% |
| Student > Doctoral Student | 3 | 6% |
| Other | 9 | 17% |
| Unknown | 9 | 17% |
| Readers by discipline | Count | As % |
|---|---|---|
| Agricultural and Biological Sciences | 24 | 46% |
| Environmental Science | 8 | 15% |
| Earth and Planetary Sciences | 5 | 10% |
| Psychology | 1 | 2% |
| Nursing and Health Professions | 1 | 2% |
| Other | 0 | 0% |
| Unknown | 13 | 25% |
Attention Score in Context
This research output has an Altmetric Attention Score of 2. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 06 January 2016.
All research outputs
#14,792,181
of 22,774,233 outputs
Outputs from Oecologia
#3,163
of 4,210 outputs
Outputs of similar age
#198,888
of 354,732 outputs
Outputs of similar age from Oecologia
#32
of 72 outputs
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