Combined stable isotope and gut contents analysis of food webs in plant-dominated, shallow lakes

• Published in: Freshwater biology Vol. 48; no. 8; pp. 1396 - 1407
• Main Authors: Jones, J. Iwan, Waldron, Susan
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-08-2003; Blackwell Science; Wiley Subscription Services, Inc
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; feeding links; fish; Fresh water ecosystems; Freshwater; Fundamental and applied biological sciences. Psychology; invertebrates; periphyton; phytoplankton; Sea water ecosystems; Synecology; zooplankton; England; United Kingdom; Great Britain; Europe; British Isles, England, Norfolk, Stradsett Hall L; British Isles, England, Norfolk, Bayfield Hall L; British Isles, England, Norfolk, Gunthorpe Hall L; British Isles, England, Norfolk, Bluestone Plantation L; Gut content; Periphyton; Trophic relation; Lacustrine environment; Spatial variation; Shallow water; Trophic chain; Vertebrata; Food web; Investigation method; feeding links; Pisces; fish; Lakes; Phytoplankton; Invertebrata; Zooplankton; invertebrates; Content analysis
• ISSN: 0046-5070; 1365-2427
• DOI: 10.1046/j.1365-2427.2003.01095.x

Summary 1. To determine feeding links between primary producers, invertebrates and fish, stable isotope analyses and gut content analyses of fish were conducted on the components of four shallow, eutrophic to hypertrophic, plant‐dominated lakes.
2. Although separation of basal resources was possible, the diets of both fish and invertebrates were broad, comprising food from different compartments (planktonic, epiphytic/benthic), as well as from different trophic levels.
3. Mixing models were used to determine the extent to which periphyton production supported higher trophic levels. Only one species of invertebrate relied upon periphyton production exclusively.
4. Fish density affected the diets of invertebrates. The response was different for planktonic and epiphytic/benthic invertebrates. The proportion of periphyton production in the diets of zooplankton appeared to increase with fish density, whilst it decreased for other invertebrates.
5. As all zooplankton samples were collected in the open water at dusk, these results are further evidence for the diurnal horizontal migration of zooplankton. Although not conclusive, they are consistent with a behavioural response by invertebrates and zooplankton in the presence of fish.