Title: Effects of differential grazing on decomposition rate and nitrogen availability in a
productive mountain grassland
Authors: María Victoria Vaieretti 1*, Ana María Cingolani 1,2, Natalia Pérez
Harguindeguy 1,2 and Marcelo Cabido 1,2
Running title: Decomposition and nitrogen availability in grassland patches maintained
by grazing
1
Instituto Multidisciplinario de Biología Vegetal, (CONICET-Universidad Nacional de
Córdoba). CC 495, (5000) Córdoba, Argentina.
2
Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba,
Av. Vélez Sarsfield 299, (5000) Córdoba, Argentina.
*Corresponding author e-mail: vvaieretti@imbiv.unc.edu.ar
Tel.: 54 351 433 1097
Fax.: 54 351 433 1056
Online Resource 1. Mean cover (%) of the most abundant species, and the chemical
and physical properties of soils (mean ± SE) for each vegetation patch type. Soil water
content was measured from January to July 2007. We calculate the average in soil water
content, for each patch type, for two periods: January to March 2007, and January to
July according to the decomposition experiment incubations. TG = tussock grasslands
Patch type
Lawns
Open TG Closed TG
Most abundant species
Poa stuckertii (Hack.) Parodi
0.3
8
71
Deyeuxia hieronymi (Hack.) Türpe
2.4
50
21.3
Eringyum agavifolium Griseb.
Lachemilla pinnata Ruiz & Pav.
Carex fuscula d' Urv.
6.4
37.7
14.1
10
9
5
3.8
1.6
0.04
Eleocharis albibracteata Nees & Meyen ex Kunth
14.3
0
0
7.9
6.4
5.8
0.6
0.2
0.01
0
0.02
0
6.1 (0.52)
0.5 (0.05)
1.8 (0.65)
5.9 (0.47)
0.5 (0.04)
2.1 (0.16)
5.8 (0.42)
0.5 (0.04)
2 (0.25)
4.9 (0.10)
4.9 (0.09)
5 (0.07)
13.9 (1.39)
32.2 (1.45)
53.9 (2.11)
0.76 (0.06)
14.6 (0.66)
32.9 (1.10)
52.5 (1.47)
0.91 (0.06)
16.4 (1.26)
33.3 (1.50)
50.3 (0.82)
0.84 (0.04)
35 (3.2)
34.7 (3.1)
30.2 (2.1)
30.4 (2.0)
34.2 (1.3)
34.5 (1.4)
Juncus uruguensis Griseb.
Muhlenbergia peruviana (P Beauv.) Steud.
Festuca circinata Griseb.
Soil characteristics
Organic C (%)
Total N (%)
P (ppm)
pH
Clay (%)
Silt (%)
Sand (%)
Bulk density (g.cm-3)
Soil water content (%) (January-March 2007)
Soil water content (%) (January-July 2007)
Online Resource 2. Chemical quality and decomposability of the litter belonging to the
each vegetation patch types and faeces. Data of litter chemical parameters and
decomposability represent means ± SE, result of averaging 10 samples of the litter
collected in September 2006 in each site of the three patch types selected. Data of
chemical quality of faeces result of averaging three sub-samples of the one compound
sample collected in September 2006, and data of faeces decomposability result of
averaging the values obtained of 10 sub-samples of the same compound sample. TG =
tussock grasslands, C:N = carbon:nitrogen; lignin:N = lignin:nitrogen; LCH =
lignin+cellulose+hemicellulose. The decomposability of litter and faeces was
determined as the percentage of dry weight loss (% DWL) of the substrates, in a
common garden experiment, after a period of incubation. 75Decomposability and
198
Decomposability = decomposability at 75 and 198 days of incubation, respectively.
Different letters indicate significant differences among patch types at p < 0.05 (mixedeffect ANOVA). Data of faeces were not including in this analysis.
Lawn
Open TG
Closed TG
Faeces
C (%)
45.7±0.27 a
46±0.48 a
46.7±0.37 a
43.3
N (%)
1.3±0.07 a
0.9±0.05 b
1±0.06 b
1.3
P (%)
0.06±0.005 a
0.05±0.003 a
0.06±0.005 a
0.16
9.2±0.43 a
6.9±0.34 b
8.2±0.45 ab
14.5
Cellulose (%)
33.8±0.69 b
37.5±0.67 a
39.1±0.48 a
32.6
Hemicellulose (%)
22.8±1.17 b
27.7±0.71 a
27.3±1 a
18.3
C:N ratio
35.7±2.07 b
50.8±2.75 a
49.5±3.31 a
32.8
7.1±0.41 b
7.5±0.24 ab
8.5±0.35 a
10.9
65.8±0.91 b
72.1±0.94 a
74.5±1.02 a
65.4
8.1±0.74 a
5.4±0.50 b
4.4±0.61 b
9.8
18±0.89 a
14.8±0.88 b
14.5±0.69 b
21
Lignin (%)
Lignin:N ratio
LCH
75
Decomposability (% DWL)
198
Decomposability (% DWL)
Online Resource 3. The significant of differences between faeces and litter of each
patch type in quality parameters and decomposability was tested with one sample ttests (because we had only one value of each parameter for faeces). In the table we
show the t values for each comparison. * p<0.05; ** p<0.01; *** p<0.001; ns, indicates
not significant differences. Values of chemical quality parameters measured and
decomposability of the litter belonging to the each vegetation patch types and faeces are
shown in Online Resource 1. Note that the litter belonging to open and closed tussock
grasslands were significantly different than faeces (p < 0.05) for all quality parameters
measured and decomposability. TG = tussock grasslands, C:N = carbon:nitrogen;
lignin:N = lignin:nitrogen; LCH = lignin+cellulose+hemicellulose, % DWL =
percentage of dry weight loss, 75Decomposability and 198Decomposability =
decomposability at 75 and 198 days of incubation, respectively.
Lawn
C (%)
8.7 ***
Open TG
Closed TG
5.6 ***
8.9 ***
N (%)
-0.2 ns
-7.3 ***
-5.5 ***
P (%)
-18.8 ***
-29.2 ***
-19.1 ***
Lignin (%)
-12.1 ***
-22.6 ***
-13.9***
Cellulose (%)
1.8 ns
7.3 ***
13.5 ***
Hemicellulose (%)
3.8 **
13.3 ***
8.9 ***
C:N ratio
1.4 ns
6.5 ***
5.1 ***
-14.4 ***
-6.9 ***
0.4 ns
7.1 ***
8.9 ***
-2.2 *
-8.6 ***
-8.9 ***
-3.5 **
-7.1 ***
-9.4 ***
Lignin:N ratio
LCH
75
Decomposability (% DWL)
198
Decomposability (% DWL)
-9.2 ***
Note: Positive t value indicates that litter quality value (of each patch type) was higher
than quality value of faeces. Negative t value indicates the opposite.
Online Resource 4. In situ decomposition (% of dry weight loss) of litter and both
common plant substrates (Muhlenbergia peruviana and Poa stuckertii) after 198 days of
incubation, in the three vegetation patch types. Different letters indicate significant
differences (ANOVA, p < 0.05) among patch types for each substrate separately. TG =
tussock grasslands.
Online Resource 5. Relationships between in situ litter decomposition (% of dry weight
loss) and, A) Muhlenbergia peruviana decomposition, B) Poa stuckertii decomposition
after 198 days of incubation, in the three vegetation patch types. r = Pearson correlation
coefficient; p = level of significance of the analysis; TG = tussock grasslands.