2.4. Data Analysis
Factorial ANOVA tested the effects of the two substrates and two organic amendments on soil properties, number, height and slenderness index, and plant cover. The assumption of homogeneity of variance was tested using Levene’s test and differences between individual means were evaluated by Tukey’s post hoc test at p < 0.05. Regression analyses were performed to test for relationships among variables. SPSS v.20 (SPSS, Inc.) was used.
The whole pool of inventoried species was analyzed looking for a pattern of species distribution through the plots by means of Detrended Correspondence Analysis (DCA). In the DCA it was assumed that plots closer to each other in the ordering diagram had a greater floristic similarity. The analyses were carried out using PAST software (Hammer et al., 2009).