2.5. Statistical analysis
The PLFA profiles were analyzed using the CANOCO software
(version 4.5, Microcomputer Power, Inc., Ithaca, NY). The amounts
of individual PLFA were analyzed based on the Principal Component
Analysis (PCA). The factors loading scores for individual PLFAs
were used to assess the relative importance of each PLFA. The
Redundancy analysis (RDA) was based on a covariance matrix,
where mol % of fatty acids was centered. The PCA as an indirect
gradient was used to analyze the major patterns of the PLFA, and to
interpret their relevance with the available environmental factors.
RDA as a direct gradient analysis, the ordination axes represented
aggregates of the environmental data that best explain the PLFA
data. All the environmental factors were tested for significance
(p < 0.05) to explain the variation in the PLFA data using a Monte
Carlo permutation test.