
TY  - JOUR
A1  - Schulze, E.-D. 
A1  - Williams, R.J. 
A1  - Farquhar, G.D. 
A1  - Schulze, W. 
A1  - Langridge, J. 
A1  - Miller, J.M. 
A1  - Walker, B.H. 
T1  - Carbon and nitrogen isotope discrimination and nitrogen nutrition of trees along a rainfall gradient in northern Australia
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 1998
VL  - 25
IS  - 4
SP  - 413
EP  - 425
KW  - carbon and nitrogen isotope ratios, nitrogen concentration, specific leaf area, drought, burning, grazing, plant functional types, Eucalyptus.
UR  - https://doi.org/10.1071/PP97113 
N2  - Carbon isotope discrimination (&#916;) and nitrogen isotope ratios, N-concentrations and specific leaf area of 50 tree species were investigated along a continental-scale transect through northern Australia over which annual rainfall varied from 1800 mm to 216 mm rainfall. Average specific leaf area (SLA, m2 kg-1) of leaves ranged from 10.7 &#177; 1.7 (av. &#177; s.d.) in N2 fixing deciduous trees to 0.8 &#177; 0.4 in spinescent sclerophylls shrubs. SLA generally decreased with increasing aridity. N2 fixing species had higher leaf N concentration (average N-concentration 20.1 &#177; 3.7 mgN g-1) than non- N2 fixing (10.8 &#177; 3.3) or spinescent species (7.05 &#177; 1.8). Community-averaged &#916; was approximately constant at rainfalls above 475 mm (average &#916; = 19.4 &#177; 1.2&#8240;). Where rainfall was less than 475 mm, &#916; decreased from 19&#8240; to 17&#8240; at 220 mm. &#916; was positively correlated with SLA. &#916; of deciduous N2 fixing species and spinescent species were 1&#8240; and 2.4&#8240; lower than in evergreen sclerophyllous species. &#916; in the N2 fixing Allocasuarina was 1.2&#8240; lower than in non- N2 fixing sclerophyllous species. The &#948;15N-values indicated N2 fixation only at high rainfall. Burning of the field layer in a Eucalyptus forest had no effect on all measured tree parameters including &#948;15N, but &#948;15N increased under grazing conditions to &#62;5&#8240;. The constant value of community averaged &#916; between 1800 and 450 mm may be the result of replacement of functional types and species. The decline in &#916; in the more arid section may be a function of both low species diversity, and a highly aseasonal and unpredictable rainfall regime. 
ER  -

