Snail communities improve submerged macrophytes growth by graze
epiphytic algae and phytoplankton in a mesocosm experiment
Abstract
The relationship between producers (e.g., macrophyte, phytoplankton and
epiphytic algae) and snails plays an important role in maintaining the
function and stability of the shallow ecosystems. A complex relationship
exists among macrophytes, epiphytic algae, phytoplankton and snails. An
outdoor mesocosm experiment with two-way factorials was carried out,
three species submerged macrophytes (Hydrilla verticillate, Vallisneria
natans or one exotic submerged plant Elodea nuttallii) and two grazing
treatments (4 snail species present or absent) to elucidate those
relationships. The results showed that the snail communities reducing
the biomass of phytoplankton and epiphytic algae indirect then enhanced
the growth of the submerged macrophytes. The macrophyte with complex
architecture supported more snail and epiphytic algae, and snails
preferred to feed on native plants. Competition drove snails change the
grazing preferences to achieve coexistence, so that led to the
assembling of snail communities towards the direction of highest
resource utilization.