Abstract
Integrating food web indicators into ecological status assessments is central to developing effective management measures that can improve degraded ecosystems. This is because they can reveal how ecosystems respond to environmental change that cannot be inferred from studying habitat, species or assemblages alone. However, the substantial investment required to monitor food webs (e.g. via stomach contents analysis) and the lack of internationally agreed approaches to assessing them has hampered their development.
Inventories of trophic interactions have been collated worldwide and across biomes, and can be applied to infer food web structure and energy flow. Here, we compile a new marine dataset containing 8092 unique predator‐prey interactions from 415,294 fish stomachs. We demonstrate how feeding guilds (i.e. groupings based on diet and life stage) could be defined systematically and in a way that is conducive to their application internationally across ecosystems; and apply them to the North Sea fish assemblage to demonstrate their responsiveness to anthropogenic pressures.
We found evidence for seven distinct feeding guilds. Differences between guilds were related to predator size, which positively correlated with piscivory, phylogeny, with multiple size‐classes of a species often in the same guild, and habitat, as pelagic, benthic and shallow‐coastal foraging was apparent.
Guild biomasses were largely consistent through time at the North Sea‐level and spatially aggregated at the regional level with change relating to changes in resource availability, temperature, fishing, and the biomass of other guilds. This suggests that fish biomass was partitioned across broad feeding and environmental niches, and changes over time were governed partly by guild carrying capacities, but also by a combination of covariates with contrasting patterns of change. Management of the North Sea ecosystem could therefore be adaptive and focused towards specific guilds and pressures in a given area.
Synthesis and applications . We propose a food web indicator which has been explicitly called for to inform policy via food web status assessment as part of the European Union’s Marine Strategy Framework Directive and the indicator toolkit supporting The Convention for the Protection of the Marine Environment of the North‐East Atlantic (the ‘OSPAR Convention').
Inventories of trophic interactions have been collated worldwide and across biomes, and can be applied to infer food web structure and energy flow. Here, we compile a new marine dataset containing 8092 unique predator‐prey interactions from 415,294 fish stomachs. We demonstrate how feeding guilds (i.e. groupings based on diet and life stage) could be defined systematically and in a way that is conducive to their application internationally across ecosystems; and apply them to the North Sea fish assemblage to demonstrate their responsiveness to anthropogenic pressures.
We found evidence for seven distinct feeding guilds. Differences between guilds were related to predator size, which positively correlated with piscivory, phylogeny, with multiple size‐classes of a species often in the same guild, and habitat, as pelagic, benthic and shallow‐coastal foraging was apparent.
Guild biomasses were largely consistent through time at the North Sea‐level and spatially aggregated at the regional level with change relating to changes in resource availability, temperature, fishing, and the biomass of other guilds. This suggests that fish biomass was partitioned across broad feeding and environmental niches, and changes over time were governed partly by guild carrying capacities, but also by a combination of covariates with contrasting patterns of change. Management of the North Sea ecosystem could therefore be adaptive and focused towards specific guilds and pressures in a given area.
Synthesis and applications . We propose a food web indicator which has been explicitly called for to inform policy via food web status assessment as part of the European Union’s Marine Strategy Framework Directive and the indicator toolkit supporting The Convention for the Protection of the Marine Environment of the North‐East Atlantic (the ‘OSPAR Convention').
Original language | English |
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Pages (from-to) | 1769-1781 |
Number of pages | 13 |
Journal | Journal of Applied Ecology |
Volume | 57 |
Issue number | 9 |
Early online date | 28 Jun 2020 |
DOIs | |
Publication status | Published (in print/issue) - 4 Sept 2020 |
Bibliographical note
Funding Information:M.S.A.T., H.P. and C.P.L. acknowledge DEFRA funding ?Appraisal of indicators of Good Environmental Status? (BX020); J.K.P. acknowledges DEFRA funding (?Fizzyfish? [MF1228]); we thank IMARES and ICES for providing stomach contents data. We thank Dr. Tom Webb for help with assigning prey functional groups and Dr. Georg H. Engelhard for constructive discussions throughout.
Publisher Copyright:
© 2020 Crown copyright. Journal of Applied Ecology © 2020 British Ecological Society.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
Keywords
- ecological status assessment
- ecosystem structure and function
- environmental change
- feeding guilds
- fishing impacts
- food web indicator
- good environmental status
- marine ecosystem