The other Selleck TPCA-1 parameters (Table 2) were submitted to a non-parametric Mann–Whitney test at p < 0.05. In order to determine statistically significant differences in the physical and chemical parameters of water between two groups of ponds—clay pits and gravel pits, sub-divided into three groups according to prevalence of macrophytes (young ponds with no macrophytes, ponds with poorly grown vegetation and ponds overgrown with compact patches selleck products of reed), thus representing different succession stages—a
non-parametric ANOVA test (Kruskal–Wallis test) was applied. Using Spearman’s non-parametric correlation of ranks, at p < 0.05, an attempt was made to identify the relationship between the parameters of water versus the type of substrate and the succession stage of plants in the analyzed ponds. Table 2 Mean values (±SD) of chemical variables of two groups of water bodies differing in type of substrate Parameter Clay pits Gravel pits T (°C) 13.17 ± 2.97 13.57 ± 2.37 O2 (mg/dm3) 10.39 ± 1.6 10.62 ± 2.06 % O2 97.67 ± 10.0 101.23 ± 19.97 BOD5 (mg O2/dm3) DMXAA in vivo 2.9 ± 0.97 4.47 ± 1.82 Conductivity (μS/cm) 436.11 ± 99.9 203.11 ± 61.13 pH 7.96 ± 0.24 8.1 ± 0.44 CO3 2− (mg/dm3) 0.42 ± 1.0 1.17 ± 2.34 HCO3 − (mg/dm3) 169.78 ± 19.6 116.53 ± 35.13 Cl− (mg/dm3) 6.57 ± 2.92 2.81 ± 2.04 SO4 2− (mg/dm3) 89.85 ± 41.97 6.52 ± 9.59 CO2 (mg/dm3) 15.45 ± 4.76 3.55 ± 5.01 NH4-N (mg/dm3) 0.12 ± 0.04 0.12 ± 0.08
Tot-N (mg/dm3) 0.89 ± 0.4 1.21 ± 0.08 PO4-P (mg/dm3) 0.01 ± 0.003 0.02 ± 0.01 Tot-P (mg/dm3) 0.07 ± 0.02 0.11 ± 0.04 P org. (mg/dm3) 0.06 ± 0.02 0.09 ± 0.03 In bold statistically
significant differences (p < 0.05) between mean values for the groups In order to correct the error due to an uneven number of faunistic samples collected from the two groups of ponds with different substrates, counts of particular species in the analyzed water bodies were replaced with values representing PJ34 HCl the mean abundance of a species in a sample, which were later included in the statistical analyses. Species diversity was determined by the number of species (S) and the Shannon–Weaver index (H′) (Krebs 1996). Next, the data employed for analyses underwent logarithmic transformation to achieve a distribution as close to the normal one as possible. In order to examine the correlations between abundance, number of species or the H′ index and each parameter, Spearman’s rho non-parametric correlation was applied at p < 0.05 (Sokal and Rohlf 1995). The correlation strength was assessed on a scale commonly used in statistics, where rXY = 0 variable not correlated, 0 < rXY < 0.1 very weak correlation, 0.1 < rXY < 0.3 weak correlation, 0.3 < rXY < 0.5 average correlation, 0.5 < rXY < 0.7 high correlation, 0.7 < rXY < 0.9 very high correlation, 0.9 < rXY < 1 almost complete correlation.