The effects of floating mats of Azolla filiculoides Lam. and Lemna minuta Kunth on the growth of submerged macrophytes

Abstract

In laboratory experiments, the growth characteristics of the submerged species Elodea nuttallii (Planch.) St. John and Potamogeton crispus L. were assessed in the presence and absence of floating mats of Azolla filiculoides Lam. and Lemna minuta Kunth. Light penetration and the development of pH and dissolved oxygen differences were monitored. The growth of P. crispus was suppressed much more than that of E. nuttallii and the effects of A. filiculoides were more severe than those of L. minuta. Findings are related to possible field responses of submerged plants under floating mats, especially their abilities to compensate for the potential suppressive effects of floating mats under natural conditions.

Competition for Light and Nutrients in Layered Communities of Aquatic Plants

“…In nutrient-limited environments, the model predicts that with increasing nutrient levels, submerged plants are outcompeted by floating plants. This pattern was also found in field studies and mesocosm studies (Portielje and Roijackers 1995;Janes et al 1996;Forchhammer 1999;Netten et al 2010). At intermediate nutrient levels, floating and submerged plants can either coexist or are alternative stable states, depending on their resource consumption.…”

“…Therefore, the occurrence of free-floating plants can be understood by studying their competition with submerged plants for light and nutrients. Although there have been empirical studies on the competition between floating and submerged plants using laboratory experiments (Janes et al 1996;Szabo et al 2010), mesocosm experiments (Feuchtmayr et al 2009;Netten et al 2010;Lu et al 2013;Smith 2014), and field experiments (Portielje and Roijackers 1995;Forchhammer 1999), the theoretical understanding of the competition between floating and submerged plants for light and nutrients is still limited.…”

CO2 and CH4 fluxes across a Nuphar lutea (L.) Sm. stand

“…Floating-leaved rhizophytes and free-floating plants are favored over submerged forms thanks to direct light and atmospheric carbon dioxide uptake (Portielje, and Roijackers 1995;Scheffer et al 2003;Pierobon et al 2010). In eutrophic shallow areas, floating-leaved plants can suppress up to 99% of the incident light, thus limiting or excluding phytoplankton and submerged vegetation (Janes et al 1996;Scheffer et al 2001;Parr et al 2002).…”

Weed biological control in the European Union: from serendipity to strategy

“…In much of its introduced range, however, A. filiculoides is a highly invasive weed that can double its biomass in less than a week (Arora and Singh 2003) to form dense floating mats across freshwater bodies. The impacts of A. filiculoides are numerous and include: reduction in dissolved oxygen in the water body and decreased light penetration through the mat, negatively affecting submerged flora and fauna; direct impediment to leisure activities such as angling and boating; threat to livestock and people when mistaken for solid land; impediment to water flow; clogging of pipes, pumps and floodgates (Gratwicke and Marshall 2001;Hill and Cilliers 1999;Janes et al 1996).…”