Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1007/s00442-022-05308-3
Licence creative commons licence
Title (Primary) Resource-dependent foraging behaviour of grazers enhances effects of nutrient enrichment on algal biomass
Author Iannino, A.; Fink, P. ORCID logo ; Vosshage, A.T.L.; Weitere, M.
Source Titel Oecologia
Year 2023
Department ASAM; FLOEK
Volume 201
Issue 2
Page From 479
Page To 488
Language englisch
Topic T5 Future Landscapes
Keywords Eutrophication; Foraging areas; Food quality; Movement ecology; Periphyton
Abstract Both the quantity and nutritional quality of food resources can strongly influence the foraging movements of herbivores, which in turn determine the strength of top-down control on primary producer biomass. Nutrient enrichment can alter the biomass and nutritional quality of primary producers, but the consequences for the foraging of herbivores and hence for top-down control are still poorly understood. In this study, we combined a two-factorial experiment (two nutrient levels × grazing by the freshwater gastropod Ancylus fluviatilis) with video analyses tracking grazers’ movements to investigate nutrient enrichment effects on spatial ranges of grazing activity and algal biomass removal. Natural stream biofilms were grown in phosphorus-enriched (P+) and phosphorus-poor flumes (P−) for two weeks before A. fluviatilis were added to the flumes and allowed to graze on biofilm for an additional 2 weeks. Total periphyton biomass was enhanced by P+ and reduced by grazer presence. However, the total grazer effect depended on the nutrient level: at the end of the experiment, on average 95% of algal cover were removed by grazing in the P− flumes versus 26% in the P+ flumes. Fast movements of A. fluviatilis were detected significantly more often in the P− treatment, whereas grazers were detected resting more often in the P+ treatment. Our results demonstrate that nutrient enrichment can increase primary producer biomass both directly and indirectly by limiting the foraging ranges of herbivores. The resulting feedback loop between reduced grazing activity and increased plant biomass might in turn exacerbate eutrophication effects on habitat structure.
Persistent UFZ Identifier
Iannino, A., Fink, P., Vosshage, A.T.L., Weitere, M. (2023):
Resource-dependent foraging behaviour of grazers enhances effects of nutrient enrichment on algal biomass
Oecologia 201 (2), 479 - 488 10.1007/s00442-022-05308-3