hrvatski

Obrasci kretanja makrozoobentosa i transport organske tvari u mahovinama sedrenih barijera

Slapišta sedrenih barijera nude povoljne uvjete za razvoj mahovinskih sastojina, a one kao mikrostaništa podržavaju izuzetnu bioraznolikost i brojnost svojti makrozoobentosa. U sprezi s brzinom strujanja vode, zadržavanje usitnjene organske tvari kao najvažnijeg energetskog resursa utječu na sastav zajednice makrozoobentosa. Cilj istraživanja je bio utvrditi obrasce kretanja makrozoobentosa u mahovinskim sastojinama i odnos spram smjerova transporta čestica organske tvari u ovom dinamičnom okolišu. Tijekom sedam dana izložili smo prirodne podloge prethodno evakuiranih mahovina u posudama čije su stijenke bile otvorene sprijeda, straga, bočno, odozgo i sa svih strana. Istraživanje je provedeno na sedrenoj barijeri Novakovića Brod (NP Plitvička jezera). Prosječna temperatura vode i pH vrijednost nisu se razlikovale između mahovinskog sloja i površinske preljevne vode. Koncentracija kisika je bila veća u površinskoj vodi u odnosu na vodu unutar mahovinskih sastojina. Provodljivost je, suprotno, bila viša u mahovinama, a manja u površinskoj vodi. Najbrojnije svojte bile su ličinke kukaca: Trichoptera, Plecoptera i Diptera (Chironomidae). Migracija makrozoobentosa u mahovinama sedrenih barijera dominantno je bila lateralna za predstavnike roda Hydropsyche. Izraženo uzvodno gibanje svojstveno je predstavnicima reda Diptera. Pronos fino i vrlo fino usitnjene organske tvari najvjerojatnije je dvojak i to: pasivan (strujom vode – nizvodno), ali i aktivan (fekalna i odumrla tvar donesena životinjama – bočno i uzvodno). Waterfalls at tufa barriers offer favorable conditions for the development of moss mats that in turn create numerous microhabitats that support extraordinary biodiversity and abundance of macroinvertebrates species. In conjunction with the flow velocity, moss mats retain particulate organic matter as a source of energy, affecting the composition of macroinvertebrates assemblages. The objective of the research was to determine the patterns of macroinvertebrate movements in moss mats in respect to the direction of organic matter particles transport in this dynamic environment. We exposed natural substrate of previously evacuated moss in containers with sides that were open from the front, rear, lateral, top, and from all sides. The survey was conducted at Novakovića Brod barrier (National Park, Plitvice Lakes). The water temperature and pH – were not different between moss mats and surface water. Oxygen concentration – was higher in surface water in comparison to moss mats. Conductivity, on the other hand was higher in moss mats than in surface water. The dominant groups were insect larvae, namely Trichoptera, Plecoptera and Diptera (Chironomidae). Macroinvertebrates migration in the moss mats of tufa barriers was predominantly lateral for the genus Hydropsyche. The upstream movement was pronounced in the representatives of Diptera. The transport of fine and ultrafine particulate organic matter is probably dual: passive (by water flow – downstream) and active (by animals – laterall and upstream).

Hydropsyche, Chironomidae, uzvodno kretanje, orijentacija životinja

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