Influence of hydraulic clam dredging and seasonal environmental changes on macro-benthic communities in the Southern Adriatic (Central Mediterranean Sea)

Table 2 PERMANOVA results based on the Bray–Curtis similarity matrix of the benthic assemblages tested according to factors (Season Se, Area Ar, Depth De), and PAIRWISE t-test obtained for the Se × Ar interaction. The degrees of freedom (df), Sum of Squares (SS); Mean Sum of Squares (MS); Pseudo-F test; p-values by permutations (P), and number of permutations (perms) are reported for each factor. In the PAIRWISE t-test, the t-test value (t), Monte Carlo p-values (P(MC)), and the average similarity (Av. S. %) are reported between Ar pairs (Margherita, Mar; Barletta, Bar, Lesina, Les; Varano, Var)

PERMANOVA results
Source of variation	df	SS	MS	Pseudo-F	P	perms
Season (Se)	1	18960	18960	20.371	0.0001	9930
Depth layer (De)	1	1185	1184.6	1.2728	0.2523	9930
Area (Ar)	3	40911	13637	14.652	0.0001	9900
Se × De	1	1141	1140.6	1.2255	0.2937	9924
Se × Ar	3	14953	4984.4	5.3555	0.0001	9923
De × Ar	3	2935	978.26	1.0511	0.4023	9896
Se × De × Ar	3	2629	876.42	0.94166	0.5582	9878
Res	98	91211	930.72
Total	113	188210
PAIRWISE test
Se × Ar interaction—Winter level
Ar pairs	t	P(MC)	perms	Av. S. (%)
Mar, Bar	2.444	0.0001	9947	56.8
Mar, Les	2.575	0.0002	9947	46.0
Mar, Var	3.774	0.0001	9950	22.4
Bar, Les	4.674	0.0001	9938	38.7
Bar, Var	5.145	0.0001	9942	22.6
Les, Var	2.997	0.0001	9939	31.8
Se × Ar interaction—Summer level
Ar pairs	t	P(MC)	perms	Av. S. (%)
Mar, Bar	1.111	0.2917	9948	57.1
Mar, Les	3.495	0.0001	9932	49.2
Mar, Var	2.643	0.0002	9959	54.0
Bar, Les	2.527	0.0001	9933	50.0
Bar, Var	2.012	0.0036	9945	51.7
Les, Var	2.319	0.0004	9920	60.3

ISSN: 2730-7182