Implications on riparian zones impacted by invasive plant colonization and copper pollution on ecosystem functions and services

Riparian landscapes are ecosystems with a high degree of biodiversity, representing the interface between aquatic and terrestrial systems. This high level of biodiversity is due to the influence of natural stressors such as flooding events or fires. However, alongside these natural stressors, there is an increasing presence of anthropogenic stressors such as chemical pollution or invasive species, which can negatively impact fundamental ecosystem functions. One of these crucial functions is provided by the riparian soil, which plays a significant role in the biogeochemical carbon cycle. Besides serving as a habitat for riparian plants, it is also important for the decomposition of dead biomass and the enrichment of soil organic matter (SOM). This function is largely carried out by the metabolism of soil micro fauna, which is sensitive to chemical pollution such as pesticides like copper sulfate used against downy mildew. Additionally, invasive plant species are suspected of negatively affecting soil microorganisms through root exudates or their growth patterns. Particularly, the Himalayan balsam (Impatiens glandulifera) is suspected of displacing native species like stinging nettle (Urtica dioica). This study investigated how soil properties change under the growth of I. glandulifera compared U. dioica, and whether the ecosystem services of riparian soil are at risk. The results of the study showed that basic soil properties such as wettability, water binding, and microstructural stability were not significantly affected by I. glandulifera. However, there were significant differences in the thermal stability of SOM and the soil’s ability to filter copper-contaminated water in soil colonized by I. glandulifera. Due to the rapid growth and high biomass accumulation of I. glandulifera, a literature review on thermodynamic processes in root-soil systems was conducted. I. glandulifera is used as an example of a highly entropic component within a dissipative structure.