Ecological Archives E089-150-A2

Aidan M. Keith, René van der Wal, Rob W. Brooker, Graham H. R. Osler, Stephen J. Chapman, David F. R. P. Burslem, and David A. Elston. 2008. Increasing litter species richness reduces variability in a terrestrial decomposer system. Ecology 89:2657–2664.

Appendix B. GLM summary statistics relating to litter identity effects.

TABLE B1. A comparison between using litter species "presence/absence" and "initial proportion" in explaining model variation. SS is the accumulated sums of squares for the five litter identity terms entered after time and block; %SS is the percentage of total sums of squares explained by these five litter identity terms.


Litter identity terms

Presence/Absence

Initial proportion

SS

%SS

SS

%SS


Log mass loss (%)

4.516

19.0

6.015

25.3

Moisture (% dry mass)

 208318

2.8

270707

3.7

Log C:N ratio

2.136

17.6

3.025

24.9

Log microbial biomass (nmol/g litter dm)

1.781

11.7

1.852

12.2

Sqrt nematode abundance (Ind./g litter dm)

61.72

3.0

128.61

6.3


 

TABLE B2. Summary GLM statistics for "species composition" when entered into the model (after fitting time and block) alone or after the five litter identity terms.


Alone
df = 30

After identity terms
df = 26

SS

F

P

SS

F

P


Log mass loss (%)

6.296

26.8

<0.001

0.282

1.4

0.110

Moisture (% dry mass)

523615

2.3

<0.001

252907

1.3

0.173

Log C:N ratio

3.367

11.4

<0.001

0.341

1.3

0.138

Log microbial biomass (nmol/g litter dm)

5.509

4.8

<0.001

3.657

3.7

<0.001

Sqrt nematode abundance (Ind./g litter dm)

265.4

1.5

0.062

136.7

0.9

0.645



[Back to E089-150]