On the occurrence, structure and distribution of deep-water Cystoseira (Phaeophyceae) populations in the Port-Cros National Park (north-western Mediterranean)

Figures & data

Fig. 1. Map of the Port-Cros National Park with submerged rocky bottoms (shading areas). Labels indicate numbered sampling sites.

Table 1. Distribution and abundance of species at the sampled sites.

		Mean density (Ind/0.25m^2 [SD])
Site	Depth (m)	Cystoseira zosteroides	Cystoseira spinosa var. compressa	Cystoseira funkii	Quadrats (n)
1	<35	−	−	+
2	<35	+	−	−
3	35	+	−	−
4	35–38	0.21 (0.47)	1.49 (1.05)	−	39
5	35–38	−	0.08 (0.37)	2.74 (1.19)	35
6	33–38	−	0.45 (0.78)	1.17 (0.74)	40
7	32–35	1.19 (1.43)	0.04 (0.22)	2.66 (1.65)	21
8	32–35	0.06 (0.24)	0.25 (0.44)	2.28 (1.22)	32
9	25–40	+	+	+
10	37–42	0.32 (0.57)	1.75 (0.83)	−	41
11	33–43	3.82 (1.07)	−	0.02 (0.15)	41
12	27–40	+	+	+
13	25–43	4.50 (2.36)	−	−	30
14	<25	−	−	−
15	<28	−	+	−
16	38–47	1.02 (0.86)	0.02 (0.07)	−	11
17	<40	+	+	−
18	30	+	+	+
19	28	+	−	+
20	30	+	−	+
21	33–35	−	+	+
Note: Site numbering as indicated in Fig. 1. Abbreviations: SD: standard deviation; +: presence; −: absence.

Fig. 2. Size distributions of the main axis with overlaid log-normal distributions of measured colonies of Cystoseira zosteroides, C. funkii and C. spinosa in sampled sites. Distributions with less than 10 measures are not shown.

Table 2. Distribution parameters data for Cystoseira species on sampled sites.

	Site	µ (cm)	SD (cm)	min (cm)	max (cm)	g 1	g 2	d	p log	n
Cystoseira zosteroides	4	6.75	4.46	3	17	2.16	4.86	0.373	0.166	8
	10	9.85	3.52	4	15	−0.26	−1.21	0.209	0.552	13
	11	8.47	1.94	3	14	0.07	0.2	0.161	0.001	157
	13	6.07	2.06	2	13.5	0.85	0.96	0.105	0.109	135
	7	11	3.37	4	21	0.69	2.18	0.135	0.728	26
Cystoseira spinosa var. compressa	4	12.67	7.05	3	35	0.93	0.55	0.069	0.941	58
	10	16.25	8.58	3	47	1.02	1.41	0.085	0.68	72
	6	7.72	3.2	3	14	0.38	−0.18	0.198	0.424	18
	8	11.63	3.51	7	18	0.72	0.37	0.156	0.973	8
Cystoseira funkii	5	8.43	2.96	3	16.5	0.41	0.21	0.129	0.084	96
	6	6.26	2.04	2	10	0.09	−0.32	0.166	0.152	47
	7	7.91	2.67	4	17	1.3	1.73	0.164	0.096	56
	8	8.49	2.88	3	15	0.1	−0.51	0.147	0.083	73
Note: Site numbering as indicated in Fig. 1. Abbreviations: µ: geometric mean sizes; SD: standard deviation; min: minimum value measured; max: maximum value measured; g 1: skewness; g 2: kurtosis; d: Kolmogorov-Smirnov d statistic; p log: Lillefors adjusted probability values for d; n: total number of plants measured.

Table 3. Probability that data between the different Cystoseira populations follow the same distribution (Kolmogorov-Smirnov test on log-transformed data).

		Cystoseira zosteroides				Cystoseira spinosa var. compressa				Cystoseira funkii
	Site	4	10	11	13	7	4	7	6	8	5	6	7
Cystoseira zosteroides	4
	10	0.03
	11	0.00	0.03
	13	0.31	0.00	0.00
	7	0.00	0.53	0.00	0.00
Cystoseira spinosa var. compressa	4	0.00	0.30	0.00	0.00	0.21
	7	0.00	0.01	0.00	0.00	0.01	0.06
	6	0.08	0.17	0.18	0.00	0.00	0.00	0.01
	8	0.04	0.95	0.16	0.00	0.95	0.71	0.13	0.09
Cystoseira funkii	5	0.01	0.18	0.33	0.00	0.00	0.00	0.00	0.49	0.17
	6	0.31	0.00	0.00	0.12	0.00	0.00	0.00	0.04	0.00	0.00
	7	0.00	0.05	0.00	0.00	0.00	0.00	0.00	0.69	0.02	0.18	0.01
	8	0.01	0.14	0.28	0.00	0.01	0.00	0.00	0.13	0.41	0.87	0.00	0.04
Note: Site numbering as indicated in Fig. 1.

Table 4. Similarity between size-specific distribution of the different species and different sites (Spearman-rank correlation coefficient calculated on 13 size classes based on a logarithmic scale).

		Cystoseira zosteroides			Cystoseira spinosa var. compressa		Cystoseira funkii
	Site	11	13	7	4	7	5	6	7
Cystoseira zosteroides	13	0.898
	7	0.588	0.335
Cystoseira spinosa var. compressa	4	0.609	0.429	0.852
	7	0.357	0.078	0.718	0.833
Cystoseira funkii	5	0.928	0.808	0.614	0.761	0.488
	6	0.805	0.842	0.209	0.311	−0.051	0.730
	7	0.877	0.792	0.66	0.755	0.448	0.894	0.695
	8	0.968	0.859	0.648	0.731	0.446	0.98	0.767	0.924
Note: Populations with less than 20 observations were not included in this analysis. Site numbering as indicated in Fig. 1.

Fig. 3. Map of the Port-Cros National Park with numbered study sites, where densities of the three Cystoseira species are represented. Diameters of the circles are proportional to the maximum densities measured: small circles: 0–1.25ind 0.25m⁻²; medium circles: 1.25–2.5ind 0.25m⁻²; big circles: >2.5ind 0.25m⁻²; triangles: presence. Specific values are shown in Table 1.