Effects of single stressors on a range of organism groups

RESIST has greatly added to the growing literature on the effects of individual stressors and has provided several case studies on bacteria (Stach et al., 2023), diatoms (Le et al., 2023, Mayombo et al., 2024), protists (Boden et al., 2023), fungi (Madge Pimentel et al., 2024; David et al., 2024), invertebrates (Madge Pimentel et al., 2024; Nguyen et al., 2023, Nguyen et al., 2024), fish (Escobar-Sierra et al., 2024) and parasites (Grabner et al., 2023; Prati et al., 2022, Prati et al., 2023), stemming from the AquaFlow and ExStream experimental systems and the field studies. In addition, we provided the first-ever comparative analysis ever on the effects of nine stressors on five organism groups (Kaijser et al. 2024). This study was performed in RESIST’s study catchments Boye and Kinzig and highlighted the differential associations of bacteria, fungi, diatoms, invertebrates and fish with individual stressors.

Regression coefficients resulting from the models that relate the distance in community dissimilarity between locations to distance of the stressor gradients between locations in the Boye and Kinzig. The light grey boxes highlight the null-region, i.e. regression coefficients that are not considered reflecting a meaningful relationship as expected by noise (-0.05 to 0.05). (modified from Kaijser et al. 2024).

Our studies on single stressor effects supported and specified our Main Hypothesis MH1, i.e. that stressors affecting water quality (and modifications of flow velocity) impact all organism groups, while other stressors affecting hydromorphology (e.g. habitat degradation) have impacts mainly on macro-organisms.