engleski

Preliminary results of epiphytic flora and vegetation found on Caulerpa taxifolia (Vahl) C.Agardh in Starigrad Bay (Hvar Island, Croatia)

Investigations were carried out by SCUBA diving in Autumn of 1997, and in Spring of 1998 at a 1 - 12 m depth in the Caulerpa taxifolia settlement in Starigrad Bay (Hvar Island). The epiphytic flora and vegetation were investigated on different parts of Caulerpa taxifolia thalii (fronds and stolons). A total of 7 samples in a permanent square (400 cm2) were collected and observed. Flora - A total of 77 species and infraspecies taxa of epiphytic algae were determined (Rhodophyta: 57 taxa, or 74%; Phaeophyta: 10 taxa, or 13%; Chlorophyta: 10 taxa, or 13%). A larger number of epiphytic taxa were determined on stolons (total: 65 taxa; Rhodophyta: 50 taxa, or 76.9%; Chlorophyta: 9 taxa, or 13.9%; Phaeophyta: 6 taxa, or 9.2%) than on fronds (total: 55 taxa; Rhodophyta: 41 taxa, or 74.4%; Phaeophyta: 10 taxa, or 18.2%; Chlorophyta: 3 taxa, or 5.4%). Vegetation - Higher values of mean total covering (RM%) of epiphytic algae were recorded on stolons (21.84%) than on fronds (18.49%). In the structural composition of epiphytic vegetation, the qualitative dominance (DN%) is predominated by the taxa of the ecological supergroups Phsl (36.4%) and Ssl (38.5%). Higher values of DN% were also found in the morphofunctional group of filamentous algae (85.5% and 75.4%) observed on both fronds and stolons. The quantitative dominance (DR%) is dominated by the taxa of ecological groups HP (54.4%) and D (36.8%) and by the taxa of calcareous encrousting algae (52.5% and 60.8%) observed on both fronds and stolons. The highest values of total mean covering (RMGi%) were recorded in the following epiphytic algal taxa: Pneophyllum fragile (4.67%), Fosliella farinosa (4.67%) and Myrionema orbiculare (4.64%) on fronds and Pneophyllum fragile (5.39%), Fosliella farinosa (5.37%), Polysiphonia scopulorum (2.17%), Titanoderma pustulatum var. pustulatum (2.14%) and Lophosiphonia obscura (2.14%) on stolons.

algae; Caulerpa taxifolia; epiphytic flora and vegetation; Hvar Island; Adriatic Sea; Croatia

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