Modelling

RESIST is the first project to systematically model the responses of a range of organism groups and ecosystem functions to degradation and recovery. Overall, the models built have predictive components and target the general question how multiple stressors and their decrease affect selected environmental, biodiversity and ecosystem functioning patterns.

Already in Phase I, we have started synthesising the results from the various experiments and field studies, amended by data and results obtained by other researchers, to provide a more comprehensive picture of stressor and recovery patterns across organism groups and ecosystem functions. We performed the first systematic meta-analysis, screening more than 20.000 papers and analysing original data from > 1.000 papers, from which we modelled the response of five organism groups (bacteria, algae, macrophytes, invertebrates and fish) to seven stressors (oxygen depletion, salinity, fine sediment enrichment, flow modification, nutrient pollution (nitrogen & phosphorus), temperature modification) (see Kaijser et al, preprint).

We found that stressors affecting water quality impact all organism groups, while other stressors affecting hydromorphology have impacts mainly on macro-organisms. We studied multiple scenarios using a stream food web model, aggregating data on individual tolerances at the level of functional groups and studied how single and multiple stressors affect food web dynamics and nutrient cycling. Functional groups exhibited a different relative tolerance ranking between the laboratory and dynamic food web contexts. Salt as a single stressor had only minor and transient effects at low level but led to the loss of one or more functional groups at high level. In contrast, high temperature, alone or in combination with salt, caused the loss of functional groups at all tested levels (see Kuppels et al., 2024).