Anticipating Biological Succession in Rehabilitation of Long-Term Operated Nature-Based Solutions for Stormwater Treatment in Different Climate Zones

Nature-based solutions (NBS) for stormwater treatment and management have been increasingly implemented in recent decades. Vegetation is important for technical functioning, performance, aesthetic appearance, and in providing other ecosystem services. However, over time, the performance of these systems changes. A lot of times, this is due to neglected maintenance. That can significantly impact the performance and appearance of stormwater solutions. Given the demanding growth conditions, other species may supplant initial plant species. Over time, plant and associated microbial communities may diversify or become poorer. Consequently, decreased performance and aesthetic appearance may cause environmental problems and conflict with the residents’ expectations. This project aims to: a) document the evolution of plants and associated bacterial and fungal communities in vertical-flow stormwater NBS over time; b) assess the impact of plants and microorganisms on the hydraulic and treatment function; c) identify gaps in the design, implementation and maintenance affecting their performance; d) develop rehabilitation concepts for malfunctioning systems based on biological succession of plants and associated microorganisms beneficial for biodiversity; and additionally e) assess the public’s perception of plant development in NBS that have been in operation for several years and the willingness of residents to participate in their maintenance. This project will contribute to a better understanding of societal attitudes and the various value systems surrounding NBS. Considering biological succession will enable the development of rehabilitation concepts beneficial for biodiversity, functionality, and appearance. The results will be valuable for NBS operators and decision-makers.