Sessile macro-epibiotic community of solitary ascidians, ecosystem engineers in soft substrates of Potter Cove, Antarctica

Figures & data

Fig. 1  Studied basibiont ascidian species: (a) Corella antarctica, dorsal view; (b) Cnemidocarpa verrucosa, lateral view; (c) Molgula pedunculata, lateral view. Scale bars: 1 cm.

Table 1 List of epibiotic taxa found on the three ascidian species. Asterisks indicate presence of a given taxa.

					Basibiont ascidian species
Phylum/division	Class	Order	Suborder	Family/genus/species	Corella antarctica	Cnemidocarpa verrucosa	Molgula pedunculata
Porifera	Demospongiae			Species P1	*	*	*
				Species P2		*
				Species P3		*	*
Cnidaria	Anthozoa	Actiniaria		Species C1	*
	Hydrozoa			Species C2		*
				Species C3	*
Bryozoa	Gymnolaemata	Cheilostomata	Anasca	Species B1	*
				Species B2	*
				Species B3	*	*	*
				Species B4			*
				Species B5	*		*
			Ascophora	Species B6		*
				Species B7	*	*	*
Annelida	Polychaeta			Species A1	*
Mollusca	Gastropoda	Sorbeoconcha	Hypsogastropoda	Buccinidae/Neobuccinum eatoni	*		*
Chordata	Ascidiacea	Stolidobranchia		Styelidae/Cnemidocarpa verrucosa	*	*
				Styelidae sp.			*
				Molgulidae/Molgula enodis	*
				M. pedunculata	*
				Molgula sp.		*
Heterokontophyta	Phaeophyceae	Desmarestiales		Desmarestiaceae/Desmarestia spp.	*		*

Fig. 2  Relative abundance (%) of higher epibiotic taxa (phylum/division) on the three basibiont ascidian species.

Table 2 Comparative parameters of basibiont ascidian species and their epibiotic community: basibiont body size (range), species richness (S′) (number of epibiotic taxa), percent cover (%), Shannon-Wiener (H’) and Evenness (J’) indices (expressed as mean±standard error). Values of F and P corresponding to ANOVA analyses between basibiont species are also indicated. Letters in parentheses indicate significant differences between species (Bonferroni post-hoc test, p<0.05).

Basibiont ascidian species	Range size in cm^2 (mean±SD)	S’ (number of macro-epibiotic taxa)	% cover	H’	J’
Corella antarctica (n=10)	23–76 (45±19)	14(A)	10.63±3.38(A)	2.23±0.03(A)	0.85±0.01(A)
Cnemidocarpa verrucosa (n=9)	23–36 (19±9)	9(B)	31.25±3.57(B)	0.27±0.03(B)	0.13±0.01(B)
Molgula pedunculata (n=9)	16–40 (25±11)^a	9(A, B)	11.79±3.57(A)	1.53±0.03(C)	0.66±0.01(C)
F (2, 25)		3.61	10.73	1176.24	2338.21
p		0.042	<0.01	<0.01	<0.01

^aThe area in Molgula pedunculata does not include the stalk.

Fig. 3  Linear regression analyses between percent cover of epibionts and available area for colonization on the basibiont ascidian individuals of Corella antarctica (Ca), Cnemidocarpa verrucosa (Cv) and Molgula pedunculata (Mp).