Tidal Exclusion Barriers Fragment an Invertebrate Community into Taxonomically and Functionally Distinct Estuarine and Wetland Assemblages

Various types of tidal barriers are used in estuaries to reduce saltwater intrusion and regulate freshwater discharge, but they often alter the physicochemical environment and faunal composition. With the use of these structures expected to increase due to climate change, there is a need to understa...

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Main Authors: Sorcha Cronin-O’Reilly, Alan Cottingham, Linda H. Kalnejais, Kath Lynch, James R. Tweedley
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Journal of Marine Science and Engineering
Subjects:
Online Access:https://www.mdpi.com/2077-1312/13/4/635
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author Sorcha Cronin-O’Reilly
Alan Cottingham
Linda H. Kalnejais
Kath Lynch
James R. Tweedley
author_facet Sorcha Cronin-O’Reilly
Alan Cottingham
Linda H. Kalnejais
Kath Lynch
James R. Tweedley
author_sort Sorcha Cronin-O’Reilly
collection DOAJ
description Various types of tidal barriers are used in estuaries to reduce saltwater intrusion and regulate freshwater discharge, but they often alter the physicochemical environment and faunal composition. With the use of these structures expected to increase due to climate change, there is a need to understand their impacts. A tidal exclusion barrier in the Ramsar-listed Vasse–Wonnerup Estuary (Australia) was found to act as an ecotone, fragmenting the estuarine gradient into two distinct components, a relatively stable marine-like environment downstream and a highly variable oligohaline to hypersaline (~0 to >100 ppt) environment upstream. The downstream regions contained a speciose and functionally rich estuarine fauna, comprising mainly polychaetes and bivalves. The upstream regions were taxonomically and functionally depauperate, containing insects, gastropods, and ostracods typically found in saline wetlands. The fragmentation of the estuary has likely impacted the provision of ecosystem services, with the fauna downstream mainly comprising burrowing species that bioturbate and, thus, aid in nutrient cycling. In contrast, the environmental conditions caused by the barrier and the resultant epifaunal invertebrate assemblages upstream aid little in bioturbation, but provide nutrition for avian fauna. These results may help in understanding the impacts of constructing new barriers in coastal ecosystems in response to climate change.
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spelling doaj-art-b67fd428f81f4247982bdc12cea3d0d92025-08-20T02:28:36ZengMDPI AGJournal of Marine Science and Engineering2077-13122025-03-0113463510.3390/jmse13040635Tidal Exclusion Barriers Fragment an Invertebrate Community into Taxonomically and Functionally Distinct Estuarine and Wetland AssemblagesSorcha Cronin-O’Reilly0Alan Cottingham1Linda H. Kalnejais2Kath Lynch3James R. Tweedley4Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, 90 South Street, Murdoch, WA 6150, AustraliaCentre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, 90 South Street, Murdoch, WA 6150, AustraliaDepartment of Water and Environmental Regulation, Government of Western Australia, Busselton, WA 6280, AustraliaDepartment of Water and Environmental Regulation, Government of Western Australia, Busselton, WA 6280, AustraliaCentre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, 90 South Street, Murdoch, WA 6150, AustraliaVarious types of tidal barriers are used in estuaries to reduce saltwater intrusion and regulate freshwater discharge, but they often alter the physicochemical environment and faunal composition. With the use of these structures expected to increase due to climate change, there is a need to understand their impacts. A tidal exclusion barrier in the Ramsar-listed Vasse–Wonnerup Estuary (Australia) was found to act as an ecotone, fragmenting the estuarine gradient into two distinct components, a relatively stable marine-like environment downstream and a highly variable oligohaline to hypersaline (~0 to >100 ppt) environment upstream. The downstream regions contained a speciose and functionally rich estuarine fauna, comprising mainly polychaetes and bivalves. The upstream regions were taxonomically and functionally depauperate, containing insects, gastropods, and ostracods typically found in saline wetlands. The fragmentation of the estuary has likely impacted the provision of ecosystem services, with the fauna downstream mainly comprising burrowing species that bioturbate and, thus, aid in nutrient cycling. In contrast, the environmental conditions caused by the barrier and the resultant epifaunal invertebrate assemblages upstream aid little in bioturbation, but provide nutrition for avian fauna. These results may help in understanding the impacts of constructing new barriers in coastal ecosystems in response to climate change.https://www.mdpi.com/2077-1312/13/4/635benthic macroinvertebratesbiological traitscoastal protectionecotoneflood preventionflow modification
spellingShingle Sorcha Cronin-O’Reilly
Alan Cottingham
Linda H. Kalnejais
Kath Lynch
James R. Tweedley
Tidal Exclusion Barriers Fragment an Invertebrate Community into Taxonomically and Functionally Distinct Estuarine and Wetland Assemblages
Journal of Marine Science and Engineering
benthic macroinvertebrates
biological traits
coastal protection
ecotone
flood prevention
flow modification
title Tidal Exclusion Barriers Fragment an Invertebrate Community into Taxonomically and Functionally Distinct Estuarine and Wetland Assemblages
title_full Tidal Exclusion Barriers Fragment an Invertebrate Community into Taxonomically and Functionally Distinct Estuarine and Wetland Assemblages
title_fullStr Tidal Exclusion Barriers Fragment an Invertebrate Community into Taxonomically and Functionally Distinct Estuarine and Wetland Assemblages
title_full_unstemmed Tidal Exclusion Barriers Fragment an Invertebrate Community into Taxonomically and Functionally Distinct Estuarine and Wetland Assemblages
title_short Tidal Exclusion Barriers Fragment an Invertebrate Community into Taxonomically and Functionally Distinct Estuarine and Wetland Assemblages
title_sort tidal exclusion barriers fragment an invertebrate community into taxonomically and functionally distinct estuarine and wetland assemblages
topic benthic macroinvertebrates
biological traits
coastal protection
ecotone
flood prevention
flow modification
url https://www.mdpi.com/2077-1312/13/4/635
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