Utjecaj submerznih makrofita i predacije riba na strukturu zooplanktona plitkih eutrofnih jezera

doctoral thesis

• Title (english): Impact of submersed macrophytes and fish predation on the structure of zooplankton in shallow eutrophic lakes
• Author: Jelena Fressl
• Mentor: Maria Špoljar (mentor)
• Committee member: Ivančica Ternjej (predsjednik povjerenstva)
• Committee member: Antun Alegro (član povjerenstva)
• Committee member: Tea Tomljanović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2020-09-21, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology
• Universal decimal classification (UDC): 57 - Biological sciences. Physical anthropology. Biodiversity

Abstract

Eutrofikacija i klimatske promjene mijenjaju funkcioniranje plitkih jezera te zahtijevaju provođenje restauracije, posebno ekološki prihvatljivim biološkim metodama promjene hranidbene mreže jezera ili održavanja submerznih makrofita. Cilj ovoga rada bio je utvrditi utjecaj submerznih makrofita, predacijskog pritiska riba, abiotičkih čimbenika i raspoloživosti hrane na strukturu zooplanktona, uključujući prehrambene skupine, veličinsku strukturu i fekunditet. Istraživanje je provedeno u dva jezera – prozirnom sa submerznim makrofitima i mutnom bez makrofita u kojem je i postavljen in situ mezokozmos. Rezultatima rada se utvrdio značaj utjecaja submerznih makrofita i predacije riba na promjene uvjeta okoliša i strukturu zooplanktona u jezerima sličnog stupnja trofije. Rezultati mezokozmosa ukazuju na sposobnost submerznih makrofita da, u relativno kratkom razdoblju, doprinesu poboljšanju kvalitete vode i održanju ravnoteže ekosustava plitkih jezera. Submerzni makrofiti su pružili sklonište od vizualnih predatora većim algivornim rašljoticalcima, koji hranjenjem smanjuju abundanciju alga, čime je potvrđena opravdanost primjene ove biološke metode u restauraciji plitkih eutrofnih jezera.

Abstract (english)

Eutrophication and climate change alter functioning of shallow lake ecosystems and demand for lake restoration, particularly by environmentally acceptable biological methods such as food web biomanipulation or maintaining submerged macrophyte stands. The aim of this thesis was to determine the impact of submerged macrophytes, fish predation, abiotic parameters and food availability on zooplankton structure, including zooplankton functional feeding guilds, size structure and fecundity. The research was conducted in two oxbow lakes – transparent lake with, and turbid lake without submerged macrophytes, in which an in situ mesocosm was set up. Results demonstrated the importance of submerged macrophytes and fish predation impacts on dissimilarities and alteration of environmental conditions zooplankton structure in lakes of similar trophic status. Mesocosm results demonstrated the ability of submerged macrophytes to improve water quality and contribute to maintaining the balance of shallow lake ecosystem. Submerged macrophytes provided refuge from visual predators to large algivorous Cladocera that can reduce phytoplankton abundance though grazing, thus confirming applicability of this biological method in shallow eutrophic lake restauration.

• Keywords: alternativna stanja / kolnjaci (Rotifera); rašljoticalci (Cladocera); veslonošci (Copepoda) / mezokozmos / trofička struktura / horizontalna i vertikalna raspodjela zooplanktona
• Keywords (english): alternative states / rotifers (Rotifera); cladocerans (Cladocera); copepods (Copepoda) / trophic structure / horizontal and vertical zooplankton distribution
• Language: croatian
• URN:NBN: urn:nbn:hr:217:269322
• Promotion: 2020
• Study programme: Title: Biology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija (doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-10-08 08:49:11