Interactions among temporal patterns determine the effects of multiple stressors.

Area of Science:

• Ecology
• Environmental Science
• Aquatic Ecosystems

Background:

• Temporal heterogeneity is a key characteristic of ecological disturbances.
• The interactive effects of multiple stressors' temporal patterns on ecosystems are poorly understood.

Purpose of the Study:

• To investigate how interactions among temporal disturbance regimes influence stream benthic assemblages.
• To determine the combined effects of sediment loading and nutrient enrichment on aquatic ecosystems.

Main Methods:

• A fully factorial field experiment was conducted.
• Tested regular and temporally variable pulse regimes for sediment and nutrient disturbances.
• Maintained equal frequency, intensity, and extent of disturbance across treatments.

Main Results:

• Interactions among temporal disturbance regimes significantly affected algal biomass and benthic assemblage composition.
• The temporal synchronization of multiple stressors did not necessarily maximize ecosystem impact.
• Demonstrated that temporal disturbance patterns drive ecosystem responses to multiple stressors.

Conclusions:

• The temporal dynamics of disturbances are critical for understanding ecosystem responses to multiple stressors.
• Effective management of compounded perturbations requires knowledge of their temporal patterns.
• Provides the first experimental evidence for the role of temporal disturbance interactions in ecosystem dynamics.