Spatio-temporal variability and restoration effects on soil bacteria communities and ecosystem functions at the Thur floodplain

Background/Question/Methods

Pristine floodplains are among the most biodiverse environments at a global scale. Floodplains provide essential services such as enhancing water quality, carbon storage, timber production, and mitigation of pollutants, and nutrient sinks. Human activity has modified floodplains world-wide, causing the loss of characteristic environmental heterogeneity, biodiversity and associated ecosystem services. Floodplains are now increasingly being restored with the aim to bring back their natural characteristics and associated functions.

Soil organisms and their interactions are fundamental to processes of soil structural formation and in the transformation and transfer of materials and nutriments but have been less studied in floodplains than in other terrestrial ecosystems. We studied the spatial and temporal (six sampling periods over one year) patterns of soil bacterial community (by T-RFLP), soil physico-chemical characteristics (temperature, water content and water level) and functions (enzymatic activity, microbial carbon and nitrogen, basal respiration) in a restored and a channelized section of River Thur (Switzerland).

Results/Conclusions

Results showed that all ecosystem functions differed significantly among seasons and among habitat and that heterogeneity was highest in the more dynamic habitats close to the river. The Channelised Section showed less heterogeneity than the restored site. Bacterial Shannon diversity was strongly positively correlated to microbial carbon and nitrogen, but negatively correlated to enzymatic activity. Bacterial diversity increased with the distance from the river in the dynamic gradient.