Results of statistical analyses for testing the relationship between diversity indices and log VP/BP.

Four different models were used: linear (LM), quadratic (QM), cubic (CM), and additive (AM). Bold characters indicate the model with the lowest Akaike Information Criterion (AIC) for each diversity index. S: OTU richness, E: Evenness, H: Shannon-Wiener diversity index, D: Simpson's index of diversity.1. Models were as follows: linear, Y∼a+ bX, quadratic, Y∼a+b (X–c)2, cubic, Y∼a+ bX + cX2 + dX3, additive, Y∼s (X), where X and Y are log VP/BP and one of the four diversity indices, respectively; a, b, c and d are parameters.2. NS p>0.05, *0.01