Direct and indirect influences of macrophyte cover on abundance and growth of juvenile Atlantic salmon
Abstract The relationships between macrophytes and the physical and biological characteristics of the environments that aquatic organisms inhabit are complex. Previous studies have shown that the macrophytes, Ranunculus (subgenus Batrachium ), which are dominant in lowland chalk streams and widespre...
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crwiley:10.1111/fwb.13979 2024-09-15T17:56:18+00:00 Direct and indirect influences of macrophyte cover on abundance and growth of juvenile Atlantic salmon Marsh, Jessica E. Jones, John Iwan Lauridsen, Rasmus B. Grace, James B. Kratina, Pavel 2022 http://dx.doi.org/10.1111/fwb.13979 https://onlinelibrary.wiley.com/doi/pdf/10.1111/fwb.13979 https://onlinelibrary.wiley.com/doi/full-xml/10.1111/fwb.13979 en eng Wiley http://creativecommons.org/licenses/by-nc-nd/4.0/ Freshwater Biology volume 67, issue 11, page 1861-1872 ISSN 0046-5070 1365-2427 journal-article 2022 crwiley https://doi.org/10.1111/fwb.13979 2024-07-30T04:21:13Z Abstract The relationships between macrophytes and the physical and biological characteristics of the environments that aquatic organisms inhabit are complex. Previous studies have shown that the macrophytes, Ranunculus (subgenus Batrachium ), which are dominant in lowland chalk streams and widespread across Europe, can enhance juvenile Atlantic salmon abundance and growth to a greater degree than other physical and biological habitat characteristics. However, mechanistic understanding of how this effect might arise requires consideration of the direct and indirect relationships among habitat characteristics that are likely to be influenced by the presence of macrophyte cover. We applied structural equation modelling to data collected during a 2‐year in‐river manipulative experiment in the River Frome (southern England, U.K.) designed to quantify the magnitude and the relative importance of direct and indirect influences of Ranunculus cover and other physical and biological variables, including water velocity, water depth, prey biomass and body size, and abundance of con‐ and hetero‐specifics, on abundance and somatic growth of 0+ salmon. Results indicated a strongly positive direct influence of Ranunculus cover on salmon abundance, as well as positive influences of Ranunculus on velocity heterogeneity and water depth that are indirectly related to decreased salmon abundance. Interestingly, there was no indication of a direct influence of Ranunculus cover on salmon growth, although Ranunculus was indirectly related to increased salmon growth through its positive influence on prey biomass, an effect mediated by velocity heterogeneity and proportion of fast velocities. These findings provide novel mechanistic insights into the key role of Ranunculus in their native lowland rivers to enhance abundance and improve conditions for multiple food web components. Strategies to maintain or enhance naturally occurring Ranunculus in these rivers are therefore likely to return wide ranging ecosystem benefits, including for ... Article in Journal/Newspaper Atlantic salmon Wiley Online Library Freshwater Biology |
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English |
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Abstract The relationships between macrophytes and the physical and biological characteristics of the environments that aquatic organisms inhabit are complex. Previous studies have shown that the macrophytes, Ranunculus (subgenus Batrachium ), which are dominant in lowland chalk streams and widespread across Europe, can enhance juvenile Atlantic salmon abundance and growth to a greater degree than other physical and biological habitat characteristics. However, mechanistic understanding of how this effect might arise requires consideration of the direct and indirect relationships among habitat characteristics that are likely to be influenced by the presence of macrophyte cover. We applied structural equation modelling to data collected during a 2‐year in‐river manipulative experiment in the River Frome (southern England, U.K.) designed to quantify the magnitude and the relative importance of direct and indirect influences of Ranunculus cover and other physical and biological variables, including water velocity, water depth, prey biomass and body size, and abundance of con‐ and hetero‐specifics, on abundance and somatic growth of 0+ salmon. Results indicated a strongly positive direct influence of Ranunculus cover on salmon abundance, as well as positive influences of Ranunculus on velocity heterogeneity and water depth that are indirectly related to decreased salmon abundance. Interestingly, there was no indication of a direct influence of Ranunculus cover on salmon growth, although Ranunculus was indirectly related to increased salmon growth through its positive influence on prey biomass, an effect mediated by velocity heterogeneity and proportion of fast velocities. These findings provide novel mechanistic insights into the key role of Ranunculus in their native lowland rivers to enhance abundance and improve conditions for multiple food web components. Strategies to maintain or enhance naturally occurring Ranunculus in these rivers are therefore likely to return wide ranging ecosystem benefits, including for ... |
format |
Article in Journal/Newspaper |
author |
Marsh, Jessica E. Jones, John Iwan Lauridsen, Rasmus B. Grace, James B. Kratina, Pavel |
spellingShingle |
Marsh, Jessica E. Jones, John Iwan Lauridsen, Rasmus B. Grace, James B. Kratina, Pavel Direct and indirect influences of macrophyte cover on abundance and growth of juvenile Atlantic salmon |
author_facet |
Marsh, Jessica E. Jones, John Iwan Lauridsen, Rasmus B. Grace, James B. Kratina, Pavel |
author_sort |
Marsh, Jessica E. |
title |
Direct and indirect influences of macrophyte cover on abundance and growth of juvenile Atlantic salmon |
title_short |
Direct and indirect influences of macrophyte cover on abundance and growth of juvenile Atlantic salmon |
title_full |
Direct and indirect influences of macrophyte cover on abundance and growth of juvenile Atlantic salmon |
title_fullStr |
Direct and indirect influences of macrophyte cover on abundance and growth of juvenile Atlantic salmon |
title_full_unstemmed |
Direct and indirect influences of macrophyte cover on abundance and growth of juvenile Atlantic salmon |
title_sort |
direct and indirect influences of macrophyte cover on abundance and growth of juvenile atlantic salmon |
publisher |
Wiley |
publishDate |
2022 |
url |
http://dx.doi.org/10.1111/fwb.13979 https://onlinelibrary.wiley.com/doi/pdf/10.1111/fwb.13979 https://onlinelibrary.wiley.com/doi/full-xml/10.1111/fwb.13979 |
genre |
Atlantic salmon |
genre_facet |
Atlantic salmon |
op_source |
Freshwater Biology volume 67, issue 11, page 1861-1872 ISSN 0046-5070 1365-2427 |
op_rights |
http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.1111/fwb.13979 |
container_title |
Freshwater Biology |
_version_ |
1810432507798093824 |