engleski

Predation risk within macrophyte stands

Aquatic vegetated habitats are very important in shaping biotic interactions, acting as food resources and both in predation opportunities and avoidance. We aimed to analyse summer macroinvertebrate community structure and functional feeding guilds in Ceratophyllum stand according to differences: 1) in microhabitats, within macrophyte stems (Cm) and macrophytes cover bed (Cb) ; and 2) in food resources and predation pressure. Water mites dominated as main predators in both microhabitats, and their abundance in macrophytes cover bed correlated negatively with dipteran larvae, their preferable food. Within stems, results suggested their predation on microcrustaceans. Ceratophyllum associated macroinvertebrate community within stems (Cm) was dominated by predators such as microturbellarians and adult heteropterans. Ceratophyllum associated benthic community (Cb) was abundant with detritivores, mainly composed of oligochaets and mayflies. The results indicated that different macroinvertebrates functional feeding guilds within macrophyte stands prayed on wide spectra of zooepiphyton (gymnoamoebae, testaceans, bdelloids) as well as monogonont rotifers, cladocerans and nauplii, which were dominant in plankton. Also, a more pronounced fish predation pressure over different macroinvertebrate groups was marked within macrophyte stems than in macrophyte cover bed. In general, macrophyte stands offer refuge for many microinvertebrates, among stems and in the bed, thus attracting their macroinvertebrates predators and fish, consequently. Besides macroinvertebrates food webs, this study suggested the existance of microzooplankton vertical migrations in shallow lakes as a predator avoidance mechanism.

Ceratophyllum; epiphyton; insect larvae; fish

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