Vulnerability of marine habitats to the invasive green alga Caulerpa racemosa var. cylindracea within a marine protected area

Stelios Katsanevakis (1) , Yiannis Issaris (1, 2) , Dimitris Poursanidis (3) , Maria Thessalou-Legaki (2)

1 HCMR - Hellenic Centre for Marine Research
2 Department of Zoology-Marine Biology
3 Department of Marine Sciences [Aegean]

The relative vulnerability of various habitat types to var. invasion was investigated in the National Marine Park of Zakynthos (Ionian Sea, Greece). The density of fronds was modelled with generalized additive models for location, scale and shape (GAMLSS), based on an information theory approach. The species was present in as much as 33% of 748 randomly placed quadrats, which documents its aggressive establishment in the area. The probability of presence of the alga within randomly placed 20 x 20 cm quadrats was 83% on 'matte morte' (zones of fibrous remnants of a former bed), 69% on rocky bottoms, 86% along the margins of meadows, 10% on sandy/muddy substrates, and 6% within meadows. The high frond density on 'matte morte' and rocky bottoms indicates their high vulnerability. The lowest frond density was observed within meadows. However, on the margins of meadows and within gaps in fragmented meadows relative high densities were observed. Such gaps within meadows represent spots of high vulnerability to invasion.

Mots clés: benthic ecology; biological pollutants; invasive macrophytes; phytobenthos; seagrass; vulnerability; Mediterranean; MPA; Greece

Stelios Katsanevakis, Yiannis Issaris, Dimitris Poursanidis, Maria Thessalou-Legaki. Vulnerability of marine habitats to the invasive green alga Caulerpa racemosa var. cylindracea within a marine protected area. Marine Environmental Research, 2010, 70 (2), pp.210. ⟨10.1016/j.marenvres.2010.05.003⟩. ⟨hal-00602594⟩