DOES THE FISH–INVERTEBRATE–PERIPHYTON CASCADE PRECIPITATE PLANT LOSS IN SHALLOW LAKES?

• DOI: 10.1890/02-0422
• Publication Date: 2007-06-04T19:29:40Z
• Authors: J. Iwan Jones; Carl D. Sayer
• Keywords: Periphyton; Dominance (genetics)

Alternative equilibria dominated by either submerged plants or phytoplankton have been described for communities in shallow lakes. A nutrient-mediated increase periphyton (algae attached to plant surfaces) is often as being responsible the loss of from lakes, yet this violates stochastic assumptions alternative equilibria. To determine if capable forcing a switch between these communities, factors governing success aquatic were surveyed 17 plant-dominated lakes Norfolk (United Kingdom) that varied nutrient concentration and fish biomass. In biomass was negatively related density periphyton. However, on correlated with grazing invertebrates, not concentration. turn, determined invertebrates. This cascade via invertebrates appeared be evident even though are heterogeneous complex. Under conditions dominance, stronger influence growth than phytoplankton. Our data support model where, within range nutrients where possible, prime determinants community structure through cascading effect predation influencing hence, plants. We suggest stochasticity required lake derived vagaries colonization reproduction.