Hide and seek : a multidisciplinary study on the ecological success of an estuarine dweller

Siegenthaler, A 2018, Hide and seek : a multidisciplinary study on the ecological success of an estuarine dweller , PhD thesis, University of Salford.

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Estuaries are dynamic systems in which biotic and abiotic conditions vary remarkably. Survival in these habitats requires flexibility in dealing with these variations, which include changes in food availability and shelter opportunities. A thorough understanding of ecological networks in these systems, therefore, relies on comprehensive information on anti-predator adaptations and trophic relationships among species. The present study focuses on two key traits of the brown shrimp Crangon crangon L. (Decapoda: Caridea), a key component of European sandy shores, namely i) its ability to conceal from predators and ii) its trophic flexibility. This shrimp is well known for its camouflage abilities and central role in the estuarine food web. Here, I applied behavioural experiments using a novel method to quantify pigment cover (PiC) to study background matching in Crangon crangon, and assessed the application of metabarcoding to define its trophic ecology in six European estuaries. Results indicate that the brown shrimp is capable of repeated fast colour adaptations and that its background matching ability is mainly influenced by presence of light and sediment colour. High levels of intra- and inter-individual variation indicated, on the other hand, a complex balance between behavioural-plasticity and environmental adaptation. Large spatial variation, on local and regional scales, in its diverse diet also confirmed the highly flexible nature of this trophic opportunist. Its diet reflected local patterns in prey item distributions, and the variation in its stomach content was evaluated as a tool for the assessment of heavy metal pollution impacts and fish biodiversity patterns in European estuaries for the first time. Overall, the results of this study yielded insights into many key factors influencing predator-prey dynamics in estuarine systems. This included the effects of environmental and behavioural factors on the evolution of animal background matching and the application of metabarcoding towards a more robust reconstruction of ecological networks.

Item Type: Thesis (PhD)
Schools: Schools > School of Environment and Life Sciences
Funders: University of Salford
Depositing User: Andjin Siegenthaler
Date Deposited: 05 Apr 2018 08:10
Last Modified: 27 Aug 2021 21:07
URI: https://usir.salford.ac.uk/id/eprint/46161

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