Composition and density of plant-associated invertebrates in relation to environmental gradients and hydrological connectivity of wetlands

Frequency of occurrence and intensity of the raised water stage determine the structure of invertebrates in the wetland ecosystems of wetland river floodplains. In order to assess the relationships in a regulated, lowland river of moderate climate, samples of water and invertebrates inhabiting submerged shoots of reed Phragmites australis Trin Ex. Stued. were taken from the middle section of the Słupia River and five of its oxbow lakes.

The wetlands differed in hydrological activity (type of connection with the river). Redundancy Analysis (RDA) revealed that hydrological connectivity accounted for 37% of the total invertebrate variance, physico-chemical conditions — 21%, while the trophic state only — 7%. Linear regression showed that the highest species richness was observed in oxbow lakes connected to the river with one arm. Diversity and species evenness increased with the increasing hydrological connectivity. The study revealed that plant-associated invertebrates inhabiting wetlands can be the main source for the reconstruction of biodiversity after floods.