Table 3.
Linear models of single and multiple environmental parameters' fit of leaf and fine root nitrogen concentration of three sub-canopy tree species
| Leaf nitrogen content (%) | Root nitrogen content (%) | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pittosporum | Coprosma | Melicytus | Pittosporum | Coprosma | Melicytus | |||||||||||||
| Sign | R2 | AIC | Sign | R2 | AIC | Sign | R2 | AIC | Sign | R2 | AIC | Sign | R2 | AIC | Sign | R2 | AIC | |
| Burrow density | + | 0.59 | −65.6 | + | 0.07 | −43.9 | + | 0.01 | −18.0 | + | 0.64 | −55.1 | + | 0.29 | −27.4 | + | 0.10 | −23.5 |
| Soil Nutrient availability | + | 0.60 | −65.7 | + | 0.36 | −49.0 | + | 0.44 | −24.8 | + | 0.64 | −54.7 | + | 0.36 | −28.9 | + | 0.53 | −31.3 |
| Soil Water content | − | 0.04 | −52.9 | − | 0.00 | −42.9 | − | 0.04 | −18.4 | − | 0.05 | −40.3 | − | 0.00 | −22.6 | − | 0.24 | −25.5 |
| Light availability | + | 0.00 | −52.2 | − | 0.07 | −43.8 | − | 0.08 | −18.9 | + | 0.01 | −39.7 | − | 0.06 | −23.4 | − | 0.01 | −22.3 |
| Burrow + Nutrient | +, + | 0.71 | −68.7 | −, + | 0.39 | −47.7 | −, + | 0.58 | −26.3 | +, + | 0.77 | −59.3 | +, + | 0.40 | −27.7 | −, + | 0.55 | −29.8 |
| Burrow + Water | +, + | 0.59 | −63.7 | +, + | 0.07 | −41.9 | +, − | 0.04 | −16.4 | +, + | 0.65 | −53.2 | +, + | 0.32 | −25.9 | +, − | 0.26 | −23.8 |
| Burrow + Light | +, − | 0.74 | −70.1 | +, − | 0.25 | −44.8 | +, − | 0.15 | −18.0 | +, − | 0.73 | −57.1 | +, − | 0.58 | −32.8 | +, − | 0.21 | −23.0 |
| Nutrient + Water | +, + | 0.64 | −65.3 | +, + | 0.43 | −48.7 | +, + | 0.48 | −23.7 | +, + | 0.68 | −54.6 | +, + | 0.46 | −29.1 | +, − | 0.55 | −29.7 |
| Nutrient + Light | +, − | 0.66 | −66.5 | +, − | 0.58 | −53.2 | +, − | 0.75 | −32.3 | +, − | 0.66 | −53.9 | +, − | 0.57 | −32.5 | +, − | 0.69 | −34.1 |
| Water + Light | −,− | 0.05 | −51.0 | −,− | 0.10 | −42.3 | −,− | 0.18 | −18.3 | −, + | 0.05 | −38.3 | −,− | 0.07 | −21.6 | −,− | 0.34 | −25.1 |
| Burrow + Nutrient + Water | +, +, + | 0.75 | −69.0 | −, +, + | 0.46 | −47.4 | −, +, + | 0.60 | −25.1 | +, +, + | 0.81 | −60.4 | +, +, + | 0.49 | −28.1 | −, +, − | 0.57 | −28.3 |
| Burrow + Nutrient + Light | +, +, − | 0.86 | −78.1 | −, +, − | 0.58 | −51.2 | −, +, − | 0.76 | −31.3 | +, +, − | 0.86 | −64.7 | +, +, − | 0.71 | −35.8 | +, +, − | 0.69 | −32.1 |
| Burrow + Water + Light | +, −, − | 0.74 | −68.4 | +, −, − | 0.26 | −43.1 | +, −, − | 0.22 | −17.0 | +, −, − | 0.73 | −55.2 | +, −, − | 0.58 | −30.8 | +, −, − | 0.44 | −25.2 |
| Nutrient + Water + Light | +, +, − | 0.68 | −65.2 | +, +, − | 0.60 | −51.6 | +, +, − | 0.75 | −30.6 | +, +, − | 0.69 | −53.1 | +, +, − | 0.60 | −31.4 | +, −, − | 0.73 | −33.9 |
Signs of model parameters are displayed for each model. The fraction of total trait variation explained by each model is represented by regression coefficients R2. Models with Akaike's information criterion (AIC) ≤ (lowest AIC + 1) were considered of high likelihood and indicated in bold. The number of tree populations is 15 for Pittosporum crassifolium, 14 for Coprosma macrocarpa, and 12 for Melicytus ramiflorus.