Table 1.

Results of statistical tests for significance of differences in drilling frequencies (DFs), abundance of predators and community composition. Bold values indicate significance level <0.01; underlined values indicate significance level <0.05. (a) Kruskal–Wallis test for differences of DFs between temporal units in the two regions. (b) The p-values from the pairwise Wilcoxon test of DFs of temporal units in the two regions were obtained using a posteriori Bonferroni correction for multiple comparisons. (c) Kruskal–Wallis test for differences in predator abundance between temporal units in the two regions. (d) The p-values from pairwise Wilcoxon test of predator abundance of temporal units in the Po prodelta, using a posteriori Bonferroni correction for multiple comparisons. (e) PERMANOVA test for differences in community composition between the two regions and between temporal units within regions. Pseudo-F-statistics and probability are listed. (f) Distance-based redundancy analysis (RDA) test for the Isonzo and Po prodeltas. The Po prodelta is analysed without the Holocene samples from the Po plain, where depth may not be a good proxy for age. F-statistics and probability are listed.

a
	chi-squared	d.f.	p‐value
Po prodelta	15.094	2	0.0005276
Isonzo prodelta	4.5819	2	0.1012

b
Po prodelta	late Holocene	late nineteenth to early twentieth century
late nineteenth to early twentieth century	0.0098
late twentieth to early twenty-first century	0.0012	0.2567

c
	chi-squared	d.f.	p‐value
Po prodelta	17.713	2	0.0001425
Isonzo prodelta	2.6181	2	0.2701

d
Po prodelta	late Holocene	late nineteenth to early twentieth century
late nineteenth to early twentieth century	0.01187
late twentieth to early twenty-first century	0.00012	1

e
PERMANOVA	F-statistics	Pr(>F)
regions (Po versus Panzano)	32.066	0.001
Po prodelta temporal units	11.207	0.001
Isonzo prodelta temporal units	7.2275	0.001

f
RDA	F-statistics	Pr(>F)
Po	2.1656	0.014
Panzano	1.5101	0.079