Composition and structure of macrophytobenthos in marine wrack on the beaches along the western coast of Istria

Plaže su prijelazna područja između morskog i kopnenog ekosustava, te su kao takva karakterizirana jedinstvenim biocenozama kao što su naplavine, koje su najčešće sačinjene od makrofitobentosa. Glavni ciljevi istraživanja bili su kvalitativno i kvantitativno utvrditi sastav makrofitobentosa unutar naplavina pronađenih na četiri postaje duž zapadne obale Istre, usporediti ih između postaja te sa zajednicama u pojasu gornjeg infralitorala. Pronađenim jedinkama smeđih makroalgi reda Fucales mjereno je fiziološko stanje neposredno nakon separacije iz naplavina te tijekom faze rehidracije (21 dan) u kamenim bazenima. Analizom naplavina determinirano je 28 različitih svojti makrofitobentosa, od kojih su smeđe alge sadržavale 10 svojti, zelene alge 9, crvene alge 8, dok se svojte morskih cvjetnica nisu determinirale, Najabundantnije svojte u naplavinama bile su Laurencia obtusa, Rytiphlaea tinctoria i Cystoseira compressa. Značajna je varijabilnost u sastavu i biomasi makrofitobentosa unutar naplavina između postaja, a uvjetovana je sastavom zajednice u neposrednom priobalju te hidrodinačkim i geomorfološkim karakteristikama područja. Sastav naplavina u ovom istraživanju odgovara sastavu svojti makroalgi u pojasu gornjeg infralitorala. Regeneracija makroalgi reda Fucales bila je većinom uspješna. Daljnja istraživanja su potrebna u istraživanju oporavka i vijabilnosti ovih vrsta, kako bi se iste mogle koristiti za in situ i ex situ restauraciju trenutno degradiranih naselja fukoidnih makroalgi.Beaches are transitional areas between marine and terrestrial ecosystems, and as such are characterized by unique biocenoses such as marine wrack, which are mostly composed of macrophytobenthos. The main objectives of the research were to qualitatively and quantitatively determine the composition of macrophytobenthos within wrack found at four stations along the west coast of Istria, to compare them between stations and with communities in the upper infralittoral zone. The physiological state of brown macroalgae of the order Fucales was measured immediately after separation from the wrack and during the rehydration phase (21 days) in stone basins. The analysis of wrack determined 28 different taxa of macrophytobenthos, of which brown algae contained 10 taxa, green algae 9, red algae 8, while no taxa were determined for seagrass. The most abundant taxa in wrack were Laurencia obtusa, Rytiphlaea tinctoria and Cystoseira compressa. Variability in the composition and biomass of macrophytobenthos within wrack is statistically significant between stations, and is predetermined by the composition of the community in infralittoral and the hydrodynamic and geomorphological characteristics of the area. The composition of wrack in this study corresponds to the composition of macroalgae taxa in the upper infralittoral zone. The regeneration of macroalgae of the order Fucales was mostly successful, but further research is needed to investigate the recovery and viability of these species, so that they can be used for in situ and ex situ restoration of currently degraded fucoid macroalgae habitats