Influence of submerged vegetation and fish abundance on water clarity in peri-urban eutrophic ponds

Abstract

Despite the presence of high nutrient concentrations, most ponds located around Brussels (Belgium) show a considerable variation in turbidity. The importance of submerged macrophytes in maintaining the clear-water state requires identification of the main factors determining macrophyte abundance and diversity in ponds and small lakes. In this study, the inter-relationships between submerged macrophyte cover, fish abundance and turbidity were investigated in 13 eutrophic peri-urban ponds. Along a turbidity gradient, vegetation switched from dominance by Stoneworts (Chara and Nitella spp.) in the clearest ponds, to dominance by Potamogeton pectinatus in ponds with a slightly lower water transparency. Despite the presence of both P. pectinatus and Stoneworts in each of the vegetated ponds, only one became dominant. Only a very low abundance (around 20%) of submerged vegetation was found in ponds of intermediate turbidity, while macrophytes were absent in turbid ponds. Multi-and univariate analysis showed a marked difference in chemical, physical and biological properties between ponds deliberately used for fish stocking and ponds that were not. Macrophyte cover was significantly negatively correlated with turbidity and plankti-benthivorous fish abundance. No such correlation was observed with piscivorous fish abundance, except for pike that were associated with a charophyte vegetation in the study ponds. The strong relationship found between fish abundance and turbidity, its negative effect on submerged vegetation cover, and the importance of submerged vegetation in controlling phytoplankton abundance, should be taken into account when selecting ponds for fish stocking. It also suggests that the study ponds have a good potential for ecological quality restoration by biomanipulation.

Periphyton and benthivorous fish affect charophyte abundance and indicate hidden nutrient loading in oligo‐ and mesotrophic temperate hardwater lakes

“…Apart from P loading, a decreasing influence of predation may have caused an increasing abundance of bream. Potential reasons include lower abundances of piscivorous northern pike ( Esox lucius ) as a consequence of climate warming (Jacobson et al, 2017) and/or declining charophyte coverage (De Backer et al, 2010), resulting in a negative feedback loop.…”

Impact of three aquatic invasive species on native plants and macroinvertebrates in temperate ponds

“…All water bodies are small and shallow ranging from 0.01 to 1.6 ha in surface area with a depth ranging from 0.5 to 6 m, thus there is no limit for macrophyte growth. Mixed water samples were used to measure environmental variables according to standard limnological procedures (methods following De Backer et al 2010). Nutrient concentrations varied considerably between ponds (Table 2).…”

Stabilizing the clear-water state in eutrophic ponds after biomanipulation: submerged vegetation versus fish recolonization

“…In addition to nutrient loading reduction (Jeppesen et al, 2007a), which is often used to restore lakes, biomanipulation, through complete or partial fish removal, is a commonly used technique to increase ecological quality in shallow lakes (Hosper & Jagtman, 1990;Jeppesen et al, 1990;Shapiro, 1990;Meijer & Hosper, 1997). Fish are known to have an important structuring role in eutrophic lakes (Jeppesen et al, 2000;De Backer et al, 2010) and their total or partial removal can have marked effects on the ecology of lakes and ponds (Lammens, 1999). By changing fish community structure through planktibenthivorous fish removal (Brönmark & Weisner, 1992), predation pressure on large zooplankton grazers (mainly Daphnia spp.)…”