Evaluating Multiple Stressor Effects on Benthic–Pelagic Freshwater Communities in Systems of Different Complexities: Challenges in Upscaling

Upscaling of ecological effects from indoor microcosms to outdoor mesocosms bridging the gap between controlled laboratory conditions and highly complex natural environments poses several challenges: typical standard water types used in experiments are not feasible large experiments. Additionally, moving micro- meso-scale, biodiversity is enhanced. We performed an microcosm experiment determine agricultural run-off (ARO) on a defined benthic–pelagic community comprising primary producers consumers, exposed ambient summer temperature +3.5 °C. Treatments were replicated two (standard Volvic Munich well water). then scaled up using ARO concentration gradient +3 °C warming above temperature, water. included same benthic macroorganisms but more periphyton plankton communities. All functional groups affected by stressors microcosms, shift macrophyte phytoplankton dominance was observed. While present, they less pronounced mesocosms, where higher may have modified responses system stressors. The stressor observed thus be masked experiments, should interpreted as “no effects”.