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Master Thesis

Fishing and climate change impacts on the trophic functioning of marine ecosystems: a worldwide meta-analysis of the past changes in transfer efficiency and kinetics

Abstract : The development of fisheries in the oceans, together with other natural and human drivers such as climate change, have led to changes in species abundance, composition, trophic interactions, and ultimately in the functioning of marine food webs such as their productivity, stability and resilience. Here, using a trophodynamic approach and global databases of catches and life history traits of marine species, we tested the hypothesis that human-induced ecological changes might have led to less productive and more unstable ecosystems, with potential adverse effects on top predators. We analyzed a set of Large Marine Ecosystems (LMEs) with contrasting trophic functioning, latitude, fishing and climate change intensities. We evaluated the changes of the speed of the biomass flow; surging up the food web from low to high trophic levels; and the trophic transfer efficiency, from 1950 to 2010. Two indices, based on these parameters, have been created, tested and validated to evaluate the ecosystem functioning changes since 1950 at the food web scale: the Time Cumulated Index (TCI) and the Efficiency Cumulated Index (ECI). Depending on the ecosystem, various species are identified as responsible of the changes. We show that those indices are not stable on the time-series and our results do not suggest simultaneously a global loss of productivity and faster speeds in the energetic transfers. Through several modelling and statistical techniques, the impact of fishing and climate change on the trophic functioning and the indices is explored.
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https://dumas.ccsd.cnrs.fr/dumas-01412988
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Submitted on : Friday, December 9, 2016 - 10:59:50 AM
Last modification on : Monday, July 6, 2020 - 3:38:22 PM
Long-term archiving on: : Thursday, March 23, 2017 - 9:22:34 AM

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  • HAL Id : dumas-01412988, version 1

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Aurore Maureaud. Fishing and climate change impacts on the trophic functioning of marine ecosystems: a worldwide meta-analysis of the past changes in transfer efficiency and kinetics. Sciences and technics of fishery. 2016. ⟨dumas-01412988⟩

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