Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1111/gcb.13581
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Title (Primary) Impaired ecosystem process despite little effects on populations: modeling combined effects of warming and toxicants
Author Galic, N.; Grimm, V.; Forbes, V.E.
Journal Global Change Biology
Year 2017
Department OESA; iDiv
Volume 23
Issue 8
Page From 2973
Page To 2989
Language englisch
Keywords dynamic energy budgets; ecosystem services; freshwater ecosystems; individual-based model; leaf litter processing; multiple stressors; population dynamics
UFZ wide themes RU5;
Abstract Freshwater ecosystems are exposed to many stressors, including toxic chemicals and global warming, which can impair, separately or in combination, important processes in organisms and hence higher levels of organization. Investigating combined effects of warming and toxicants has been a topic of little research, but neglecting their combined effects may seriously misguide management efforts. To explore how toxic chemicals and warming, alone and in combination, propagate across levels of biological organization, including a key ecosystem process, we developed an individual-based model (IBM) of a freshwater amphipod detritivore, Gammarus pseudolimnaeus, feeding on leaf litter. In this IBM, life history emerges from the individuals’ energy budgets. We quantified, in different warming scenarios (+1–+4 °C), the effects of hypothetical toxicants on suborganismal processes, including feeding, somatic and maturity maintenance, growth, and reproduction. Warming reduced mean adult body sizes and population abundance and biomass, but only in the warmest scenarios. Leaf litter processing, a key contributor to ecosystem functioning and service delivery in streams, was consistently enhanced by warming, through strengthened interaction between the detritivorous consumer and its resource. Toxicant effects on feeding and maintenance resulted in initially small adverse effects on consumers, but ultimately led to population extinction and loss of ecosystem process. Warming in combination with toxicants had little effect at the individual and population levels, but ecosystem process was impaired in the warmer scenarios. Our results suggest that exposure to the same amount of toxicants can disproportionately compromise ecosystem processing depending on global warming scenarios; for example, reducing organismal feeding rates by 50% will reduce resource processing by 50% in current temperature conditions, but by up to 200% with warming of 4 °C. Our study has implications for assessing and monitoring impacts of chemicals on ecosystems facing global warming. We advise complementing existing monitoring approaches with directly quantifying ecosystem processes and services.
Persistent UFZ Identifier
Galic, N., Grimm, V., Forbes, V.E. (2017):
Impaired ecosystem process despite little effects on populations: modeling combined effects of warming and toxicants
Glob. Change Biol. 23 (8), 2973 - 2989