When things don't add up: quantifying impacts of multiple stressors from individual metabolism to ecosystem processing

Authored by Volker Grimm, Valery E Forbes, Nika Galic, Lauren L Sullivan

Date Published: 2018

DOI: 10.1111/ele.12923

Sponsors: No sponsors listed

Platforms: NetLogo

Model Documentation: ODD Flow charts Mathematical description

Model Code URLs: Model code not found

Abstract

Ecosystems are exposed to multiple stressors which can compromise functioning and service delivery. These stressors often co-occur and interact in different ways which are not yet fully understood. Here, we applied a population model representing a freshwater amphipod feeding on leaf litter in forested streams. We simulated impacts of hypothetical stressors, individually and in pairwise combinations that target the individuals' feeding, maintenance, growth and reproduction. Impacts were quantified by examining responses at three levels of biological organisation: individual-level body sizes and cumulative reproduction, population-level abundance and biomass and ecosystem-level leaf litter decomposition. Interactive effects of multiple stressors at the individual level were mostly antagonistic, that is, less negative than expected. Most population- and ecosystem-level responses to multiple stressors were stronger than expected from an additive model, that is, synergistic. Our results suggest that across levels of biological organisation responses to multiple stressors are rarely only additive. We suggest methods for efficiently quantifying impacts of multiple stressors at different levels of biological organisation.

Tags

Individual-based model Population dynamics Dynamics Biodiversity Ecosystem services systems growth Populations Plant Inhibition Metaanalysis Daphnia-magna Reproduction Responses Ecological risk-assessment Energy budgets Synergism Antagonism Detritivores Stressor interactions