Potential for the development of submerged macrophytes in eutrophicated shallow peaty lakes after restoration measures

Abstract

Biomanipulation of eutropicated peaty lakes has rarely been successful; clear water with dense macrophyte stands fails to develop in most cases. It was unclear whether (1) high turbidity due to resuspension by benthivorous fish or wind is the major cause of low macrophyte density or whether (2) the establishment of submerged macrophyte stands is prevented by a lack of propagules, low cohesive strength of the lake sediment, high concentrations of phytotoxics, grazing by waterfowl and/or shading by periphyton growth. These hypotheses were tested in an experiment in a shallow peat lake in the Netherlands (Terra Nova). Removal of fish from a 0.5 ha experimental site resulted in clear water and the development of a dense (90% coverage) and species-rich (10 species) submerged vegetation. At a fish-stocked site and a control site the water remained turbid and dense macrophyte stands did not develop. The establishment of submerged macrophytes appeared not to be limited by a lack of propagules. Introduced plants grew poorly in turbid water, but very well in clear water. Exclosures showed that bird grazing reduced the plant biomass. In clear water grazing seemed to enhance the vegetation diversity. Periphyton development did not prevent plant growth in clear water. After the experiment, the fish stock was greatly reduced in the whole lake (85 ha), to test if (3) in a large lake, submerged macrophyte stands will not develop after biomanipulation. In the first season after fish reduction, transparency increased and species-rich submerged macrophyte stands developed, covering 60% of the shallow parts of the lake. Most of the species known to have occurred in the past re-established. The results indicate that high turbidity caused by benthivorous fish in combination with bird grazing were the major causes of the absence of submerged macrophyte stands in this lake. Abiotic conditions after the clearing of the lake were suitable for the growth of macrophytes. We infer that the restoration potential of submerged macrophyte stands in eutrophicated peaty lakes can be high, and results can be obtained quickly.

Charophyte occurrence in Ceratophyllum demersum stands

“…7) charophytes cooccurred with Ceratophyllum demersum within the stands dominated by this common macrophyte. Available in literature data seem to confirm our findings indicating that charophytes can occur in Ceratophyllum demersum stands when they have favorable growth conditions (Lehmann & Lachavanne, 1999;Tracy et al, 2003;Mäemets & Freiberg, 2005;Bazarova & Itigilova, 2006;Kłosowski, 2006;van de Haterd & Ter Heerdt, 2007;Kraska, 2009;Pełechaty et al, 2009;Gąbka et al, 2010). Fig.…”

Restoring macrophyte diversity in shallow temperate lakes: biotic versus abiotic constraints

“…The question whether herbivores can prevent the colonisation of macrophytes in restored shallow water bodies is debated. Experiments where macrophytes were transplanted in restored lakes showed that herbivores (large fish and waterfowl) strongly reduced macrophyte biomass (Lauridsen et al, 1993;Sondergaard et al, 1996;Lauridsen et al, 2003b;Irfanullah & Moss, 2004;Van de Haterd & Ter Heerdt, 2007;Moore et al, 2010). However, Perrow et al (1997) and Strand & Weisner (2001) found no significant reduction due to herbivory by fish and birds in restored lakes of the biomass of macrophytes that had developed spontaneously, whereas Hilt (2006) found a more than 90% reduction of P. pectinatus vegetation through grazing.…”

“…In lakes where sediment contributes most to water turbidity and sediment dynamics prevent macrophyte recruitment, the creation of shelter and removal of sediment disturbing fish will be necessary; as shown by lake biomanipulation studies (Gulati & Van Donk, 2002;Sondergaard et al, 2007;Gulati et al, 2008). When optimal light conditions are re-established, plants can respond fast by germination and colonisation of the shallow water body (Van de Haterd & Ter Heerdt, 2007). However, whereas biomanipulation can initially result in a strong expansion of macrophyte vegetation, which can be species rich, the community often rapidly changes and becomes dominated by eutrophic species.…”

“…The ongoing eutrophication of freshwater bodies (Carpenter et al, 1998;Tilman et al, 2001) has induced a decline or disappearance of macrophytes from many shallow water ecosystems Brouwer & Roelofs, 2001;Gulati & van Donk, 2002;Lamers et al, 2002). This has been observed in many shallow lakes in densely populated areas, for instance in the Loosdrecht lakes (Best et al, 1984;Gulati & van Donk, 2002;Van de Haterd & Ter Heerdt, 2007) and Lake Veluwemeer (Van den Berg et al, 1999;Ibelings et al, 2007) in The Netherlands, Lake Fure (SandJensen et al, 2008) and Lake Arresø in Denmark and the Müggelsee in Germany (Korner, 2001). Increased nutrient availability can initially stimulate macrophyte growth as long as the water remains clear (Lombardo & Cooke, 2003;Nagasaka, 2004;Feuchtmayr et al, 2009).…”

Sustainable Management of Eutrophic Lakes and Reservoirs

“…The submerged vegetation increased to 30%. In another report [116] 60% coverage in shallow areas was observed. Rao et al [87] reported that larger Tilapia should be selectively harvested because the large Tilapia fed on macrophytes while small Tilapia fed on periphyton, seston, and detritus.…”