2022 Early Hearing Detection & Intervention Virtual Conference
March 13 - 15, 2022
5/20/2019 | 10:15 AM - 10:30 AM | QUANTIFYING THE EFFECTS OF ALTERED HYDROLOGY AND FOOD-WEB STRUCTURE ON ECOSYSTEM CARRYING CAPACITY IN A FLOODPLAIN RIVER | 250 DE
QUANTIFYING THE EFFECTS OF ALTERED HYDROLOGY AND FOOD-WEB STRUCTURE ON ECOSYSTEM CARRYING CAPACITY IN A FLOODPLAIN RIVER
There is widespread evidence for a reduction in biomass of tertiary consumers such as large predatory fish in lowland rivers. These declines are caused by a myriad of factors such as overfishing, habitat loss, fragmentation, declining water quality and lost spawning cues. Recently research has also emphasized the role of altered food-webs and changes in energy production as factors that may limit the current carrying capacity of higher consumers in these systems. Here we present a novel ecosystem approach to quantifying the effects of altered hydrology and altered food-web structure on the carrying capacity of large-bodied native fish in the Murray River, southeastern Australia. We combine estimates of current and historical primary production with current and historic food-webs to estimate energy available to support native fish species such as Murray cod and golden perch. Our results suggest that river regulation and food-web changes have reduced energy fluxes to these native tertiary consumers by roughly 70% relative to historic levels, due to reduced production and the presence of trophic dead ends (notably carp). Both limitations will need to be addressed contemporaneously if carrying capacity of native fish is to be restored.
- Fish
- Floodplain
- Hydrology
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Presenters/Authors
Nick Bond
(), La Trobe University, n.bond@latrobe.edu.au;
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Jian Yen
(), University of Melbourne, j.yen@unimelb.edu.au;
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James Thomson
(), Monash University, Melbourne, Victoria, Australia, jim.thomson@delwp.vic.gov.au;
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Keller Kopf
(), Charles Sturt University, rkopf@csu.edu.au;
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Daryl Nielsen
(), CSIRO, Daryl.Nielsen@csiro.au;
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Nicole McCasker
(), Charles Sturt University, nmccasker@csu.edu.au;
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Paul Humphries
(), Charles Sturt University, PHumphries@csu.edu.au;
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John Morrongiello
(), University of Melbourne, john.morrongiello@unimelb.edu.au;
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David Crook
(), La Trobe University, David.Crook@latrobe.edu.au;
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Paul Reich
(), DELWP, p.reich@delwp.vic.gov.au;
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Mark Kennard
(), Australian Rivers Institute, Griffith University, m.kennard@griffith.edu.au;
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Gavin Butler
(), NSW Dept of Primary Industries, gavin.butler@dpi.nsw.gov.au;
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