title: Individual and combined suppressive effects of submerged and floating-leaved macrophytes on algal blooms.
abstract: Shallow lakes and ponds are often characterised either by clear water with abundant submerged macrophytes or by turbid water with abundant phytoplankton. Blooms of toxic filamentous blue-green algae (cyanobacteria) often dominate the phytoplankton community in eutrophic lakes, which threatens ecological functions and biodiversity of freshwater ecosystems. We studied a simple lake model in order to evaluate individual and combined suppressive effects of rooted submerged and rooted floating-leaved macrophytes on algal blooms. Floating-leaved plants are superior competitors for light, whereas submerged plants absorb and reduce available phosphorus in a water column that rooted floating-leaved plants exploit to a lesser extent. We found that mixed vegetation that includes both submerged and floating-leaved plants is more resistant than vegetation comprised by a single plant type to algal invasion triggered by phosphorus loading. In addition, competitive exclusion of submerged plants by floating-leaved plants may promote an algal bloom. These predictions were confirmed by the decision tree analysis of field data from 35 irrigation ponds in Hyogo Prefecture, Japan.
authors.affiliation: Department of Information and Computer Sciences, Faculty of Sciences, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan. seto@ics.nara-wu.ac.jp
authors.forename: Mayumi
authors.initials: M
authors.lastname: Seto
authors.forename: Noriko
authors.initials: N
authors.lastname: Takamura
authors.forename: Yoh
authors.initials: Y
authors.lastname: Iwasa
mesh_terms: D000458:Cyanobacteria / Q000502:physiology*; D005068:Eutrophication / Q000502:physiology*; D060106:Lakes / Q000382:microbiology*; D008954:Models, Biological; D010839:Phytoplankton / Q000502:physiology*; D010944:Plants