Multiple stressors in rotifer communities: Effects of predation, climate change, and brownification

Huan Zhang

    Research output: ThesisDoctoral Thesis (compilation)

    329 Downloads (Pure)

    Abstract

    Most organisms on Earth live in an environment where they are exposed to multiple pressures, including predation and climate change. In many aquatic ecosystems, organisms have to handle additional challenges such as brownification, co-occurring with climate warming. Despite the growing recognition of impacts of climate warming or brownification on the freshwater communities, little is known on how synergistic effects from multiple environmental changes will affect community dynamics in freshwater ecosystems. In this thesis I investigate the effects of predation, climate changes, and brownification on the rotifer community dynamics.
    I show that predation has strong effects not only on population growth but also on inducible morphological defenses in rotifers. Larval fish feed extensively on rotifer prey and reduces spine length of a common rotifer (Keratella cochlearis) both through induction of shorter spines and selective predation on long-spined individuals. Furthermore, I demonstrate that rotifer prey can detect and respond appropriately in opposite directions to different sizes and feeding modes of predators by being plastic in spine and body size.
    My studies show that rotifer community will start to establish earlier in spring under a climate-warming scenario, whereas it would also decline earlier due to increased predation pressure. Furthermore, I show that in a future climate scenario with increased temperature variations and frequency of extreme temperatures, predatory copepods benefit from heat waves due to their ability of initiating diapause at an almost adult stage and rapidly responding to temperature variation, while rotifers suffer from a higher predation pressure. Hence, in a broader perspective my studies suggest that differences in life history traits will affect predator-prey interactions, and consequently alter community dynamics, in a future climate change scenario. However, the effects of brownification on establishment and growth in the rotifer community were less pronounced, or even negligible.
    Original languageEnglish
    QualificationDoctor
    Awarding Institution
    Supervisors/Advisors
    • Hansson, Lars-Anders, Supervisor
    • Rengefors, Karin, Supervisor
    Award date2017 Nov 2
    Place of PublicationLund
    Publisher
    ISBN (Print)978-91-7623-426-6
    ISBN (electronic) 978-91-7623-427-3
    Publication statusPublished - 2017 Oct

    Bibliographical note

    Defence details
    Date: 2017-11-02
    Time: 09:00
    Place: Lecture hall “Blå hallen”, Ecology building, Sölvegatan 37, Lund
    External reviewer(s)
    Name: Declerck, Steven
    Title: Dr.
    Affiliation: Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
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    Subject classification (UKÄ)

    • Biological Sciences

    Free keywords

    • Climate change
    • community dynamic
    • brownification
    • heat wave
    • inducible defense
    • rotifer
    • plasticity
    • multiple stressors
    • Predation
    • prey

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