Epifauna associated to the introduced Gracilaria vermiculophylla (Rhodophyta; Florideophyceae: Gracilariales) and comparison with the native Ulva rigida (Chlorophyta; Ulvophyceae: Ulvales) in an Adriatic lagoon

Figures & data

Figure 1. Marinetta Lagoon and study sites (StU: site U; StG: site G).

Figure 2. Average amount of macroalgae (as gDW) at the study sites (site G: StG; site U: StU; black: Gracilaria vermiculophylla; Grey: Ulva rigida; bars are SD). Ma06: March 2006; Ju06: June 2006; etc.

Figure 3. Average composition of epifaunal assemblages at each sampling site (site G: StG; site U: StU; bars are SD).

Table I. PERMANOVA: result of main test from unrestricted permutation of raw data.

Source	df	SS	MS	Pseudo-F	P(perm)	P(MC)
Habitat (H)	1	50760	50760	11.863	0.0119	0.0004
Season (S)	3	22604	7534.6	1.8449	0.0449	0.0301
Year (Y)	4	47357	11839	17.71	0.0001	0.0001
H × S	3	9964.2	3321.4	1.1623	0.3298	0.3185
H × Y	4	17116	4278.9	6.4006	0.0001	0.0001
S × Y	12	49007	4084	6.109	0.0001	0.0001
H × S × Y	12	34293	2857.7	4.2747	0.0001	0.0001
Residuals	80	53481	668.52
Total	119	2.85E+05

Table II. Summary of differences in abundance of major epifaunal taxa found on Gracilaria versus Ulva habitats.

Species	Gracilaria	Ulva	Avg	% contribution to	% cumulative
	avg abundance	avg abundance	dissimilarity	overall dissimilarity	contribution
Gammarus aequicauda	1.14	4.79	20.38	28.61	28.61
Ecrobia ventrosa	2.64	0.63	12.03	16.88	45.5
Arcuatula senhousia	1.96	2.21	11.69	16.41	61.91
Microdeutopus gryllotalpa	0.56	1.5	7.91	11.11	73.02
Hydroides dianthus	0.49	0.67	4.17	5.86	78.88
Ficopomatus enigmaticus	0.19	0.42	2.36	3.32	82.19
Cerastoderma glaucum	0.3	0	1.83	2.57	84.76
Idothea baltica	0.2	0.24	1.82	2.55	87.31
Monocorophium insidiosum	0.3	0	1.67	2.35	89.66
Mytilus galloprovincialis	0.02	0.24	1.44	2.03	91.68

Figure 4. Ordination plot of epifaunal assemblages. Point acronyms: year (7: 2007; 8: 2008; etc.); site (G and U), and time (ma: March; ju: June; etc.) of sampling (black triangle: Gracilaria vermiculophylla; white triangle: Ulva rigida).

Figure 5. Epifaunal community descriptors (average values) at the two sites (site G: StG; site U: StU): S, number of species; N, abundance (as N ind g DW⁻¹), and H’, diversity. March 2006: 6ma; June 2006: 6ju; etc.

Figure 6. Average composition of feeding strategies at the two sites (site G: StG; site U: StU): suspension feeders (SF), deposit feeders (DF), predators (P) and herbivores (H).