Submerged macrophytes as a habitat for zooplankton development in two reservoirs of a flow-through system (Papuk Nature Park, Croatia)

Abstract

-In order to determine the influence of lentic habitats and macrophyte stands on the plankton development and seston flux, an investigation of zooplankton was carried out in the karst Jankovac flowthrough system (Papuk Nature Park, Croatia). The system was characterized by low abundance (1-116 ind.L x1 ) and high diversity of identified zooplankton. Eighty-six taxa were recorded, comprising 57 rotifers, 15 cladocerans, 8 copepods and 6 members of other groups of organisms. The spatial oscillations of environmental parameters and biocoenosis assemblage revealed statistically significant differences between lotic and lentic habitats, as well as between vegetated and non-vegetated stations. These differences mainly respond to higher concentration of food resources and zooplankton/zooseston abundance and biomass in lentic, especially vegetated, habitats. This is also proved by results of principal component analysis (PCA), which suggested that the main drivers of development of the planktonic community were the food resources and the avoidance of flow velocity. Accordingly, shoreline areas with submerged macrophyte stands of Hippuris vulgaris L. were the most productive parts, represented by highest zooplankton abundance, biomass and biodiversity. Flow velocity significantly affected crustaceans assemblage, so that higher abundances of the larger cladocerans and copepods were achieved in vegetated stations with low flow velocity, while rotifers showed to be rheotolerance organisms. On the other hand, the longitudinal discontinuum of the stream channel by two man-made reservoirs could offer new habitats to enrich seston with organic particles and bioseston. The results of our study pronounce the need for further monitoring of this hydrosystem, especially considering biodiversity and microhabitats conservation.

Hydrology driven changes in the rotifer trophic structure and implications for food web interactions

“…Short generation times (Gillooly, 2000) and the production of large numbers of offspring enable the development of abundant rotifer communities even where slow water currents occur (Baranyi et al, 2002;Keckeis et al, 2003). When combined with their ability to adapt to short-term environmental variability (Locke & Sprules, 1993;Moore & Folt, 1993;Špoljar, Dražina, Šargač, Kralj Borojević, & Žutinić, 2012), this has made rotifers successful organisms in highly variable and dynamic floodplain ecosystems. Although rotifers are considered weak swimmers compared to microcrustacean groups, they can undergo rapid vertical migration as a consequence of their ability to actively control their location and select sites (Hofmann, 1987;Mikschi, 1989).…”

Disentangling food webs interactions in the littoral of temperate shallow lakes

“…The structural heterogeneity of habitats in the Sutla backwater related to the complex macrophyte architecture, significantly enhanced the biodiversity (Kuczyńska-Kippen, 2003;Špoljar et al, 2012a;Chaparo et al, 2015;Dražina et al, 2016), as different from the structural simplicity and biodiversity scarcity in Zajarki gravel pit (Špoljar et al, 2011, Špoljar, 2013). Snails, water mites and insect larvae are the main consumers of epiphyton (Liboriussen et al, 2005), maintain macrophyte light conditions i.e.…”

Effects of Submerged Plants on the Growth of Eutrophic Algae and Nutrient Removal in Constructed Wetlands

“…At the same time many submerged plants can produce allelochemicals to kill or inhibit algae in the water [10] [11]. Submerged plants can also supply a large surface area for macrozooplankton adhesion, feeding a large number of phytoplankton, which thus can control alga population indirectly [12]. Submerged plants can realize the purification of water through adsorption of biological and nonbiological suspended materials in water, improve water transparency and increase the dissolved oxygen of water [13] [14].…”