Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1111/gcb.16026
Licence creative commons licence
Title (Primary) Water diversion and pollution interactively shape freshwater food webs through bottom-up mechanisms
Author de Guzman, I.; Altieri, P.; Elosegi, A.; Pérez-Calpe, A.V.; von Schiller, D.; González, J.M.; Brauns, M.; Montoya, J.M.; Larrañaga, A.
Source Titel Global Change Biology
Year 2022
Department FLOEK
Volume 28
Issue 3
Page From 859
Page To 876
Language englisch
Topic T5 Future Landscapes
Data and Software links
Keywords bottom-up mechanisms ; food web ; food web complexity ; pollution ; stable isotopes ; water diversion
Abstract Water diversion and pollution are two pervasive stressors in river ecosystems that often co-occur. Individual effects of both stressors on basal resources available to stream communities have been described, with diversion reducing detritus standing stocks and pollution increasing biomass of primary producers. However, interactive effects of both stressors on the structure and trophic basis of food webs remain unknown. We hypothesised that the interaction between both stressors increases the contribution of the green pathway in stream food webs. Given the key role of the high-quality, but less abundant, primary producers, we also hypothesised an increase of food web complexity with larger trophic diversity in presence of water diversion and pollution. To test these hypotheses, we selected four rivers in a range of pollution subject to similar water diversion schemes, and we compared food webs upstream and downstream of the diversion. We characterised food webs by means of stable isotope analysis. Both stressors directly changed the availability of basal resources, with water diversion affecting the brown food web by decreasing detritus stocks, and pollution enhancing the green food web by promoting biofilm production. The propagation of the effects at the base of the food web to higher trophic levels differed between stressors. Water diversion had little effect on the structure of food webs, but pollution increased food chain length and trophic diversity, and reduced trophic redundancy. The effects at higher trophic levels were exacerbated when combining both stressors, as the relative contribution of biofilm to the stock of basal resources increased even further. Overall, we conclude that moderate pollution increases food web complexity and that the interaction with water abstraction seems to amplify this effect. Our study shows the importance of assessing the interaction between stressors to create predictive tools for a proper management of ecosystems.
Persistent UFZ Identifier
de Guzman, I., Altieri, P., Elosegi, A., Pérez-Calpe, A.V., von Schiller, D., González, J.M., Brauns, M., Montoya, J.M., Larrañaga, A. (2022):
Water diversion and pollution interactively shape freshwater food webs through bottom-up mechanisms
Glob. Change Biol. 28 (3), 859 - 876 10.1111/gcb.16026