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Eco-engineered mangroves provide complex but functionally divergent niches for estuarine species compared to natural mangroves

Citation

Tachas, JN and Raoult, V and Morris, RL and Swearer, SE and Gaston, TF and Strain, EMA, Eco-engineered mangroves provide complex but functionally divergent niches for estuarine species compared to natural mangroves, Ecological Engineering, 170 Article 106355. ISSN 0925-8574 (2021) [Refereed Article]


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DOI: doi:10.1016/j.ecoleng.2021.106355

Abstract

There is growing demand for novel coastal protection approaches that also provide co-benefits such as enhanced biodiversity. Rock-fillets, which are used to stabilise eroding banks in estuaries, can be colonised by mangroves, and may provide habitat for estuarine fauna. However, it is unknown whether hybrid mangrove/rock-fillet habitats are functionally equivalent to natural mangroves, for estuarine fauna. To determine whether hybrid mangrove habitats are functionally equivalent to natural mangroves, we used δ13C and δ15N stable isotope analyses to describe the isotopic niche space and overlap of estuarine species in these two habitats across three estuaries in NSW, Australia. Using a Bayesian standard ellipse analysis of isotopic niche area, over half the 12 species observed had larger isotopic niche areas in natural mangroves compared to hybrid habitats, however there were no clear patterns for species between habitats. Natural mangroves and hybrid rock-fillet habitats were isotopically distinct for all species sampled (low proportional overlap, 019%) suggesting they are not, at present, wholistically functionally equivalent. Estuarine communities from the two habitat types, however, had similar isotopic niches. Hybrid communities displayed a broader range of δ13C values compared to natural mangroves, suggesting mangrove/rock-fillet habitats have a more diverse range of basal food sources. These findings demonstrate the potential for defence solutions to provide unique co-benefits by supporting food webs, but also that natural habitats provide unique ecosystem services that should be protected and rehabilitated where possible. Future modelling and monitoring of habitat utilisation and species performance could provide further insight into the co-benefits and trade-offs of hybrid habitats.

Item Details

Item Type:Refereed Article
Keywords:ecological engineering, hybrid ecological engineering, living shorelines, restoration, rock-fillets, shoreline protection, stable isotope analysis
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Assessment and management of benthic marine ecosystems
UTAS Author:Strain, EMA (Dr Beth Strain)
ID Code:145171
Year Published:2021
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2021-07-06
Last Modified:2021-08-25
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