Feasibility of restoring native oyster reefs in highly modified urban estuaries
Date
2026
Authors
Kenny, I.
Connell, S.D.
McAfee, D.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Restoration Ecology, 2026; 1-8
Statement of Responsibility
Ishtar Kenny, Sean D. Connell, Dominic McAfee
Conference Name
Abstract
Introduction: Urbanized estuaries are highly altered systems characterized by modified shorelines, degraded marine habitats, and abundant non-native species. In South Australia's largest urbanized estuary, community-based restoration initiatives aim to restore native flat oyster reefs (Ostrea angasi) lost over a century ago. However, extensive modification of the estuary and ubiquity of non-native Pacific oysters (Magallana gigas) create uncertainty on the feasibility of restoration. Objectives: This project assessed whether hand-held restoration units (shell gabion baskets) deployed by community volunteers can facilitate recruitment and habitat formation by O. angasi, and whether specific depths limit recruitment of M. gigas. Methods: Initiated by a fishing conservation charity, this community-led project deployed 70 restoration units to assess site suitability and restoration efficiency for larger-scale reef restoration. Restoration feasibility was evaluated by (1) quantifying oyster recruitment and biodiversity 1 year after deploying units, and (2) deploying settlement substrates across a depth gradient to identify depths that favor native oysters while limiting non-native oyster recruitment. Results: Restoration units supported high O. angasi recruitment (mean ± 1 SE = 1144 ± 223 per unit) and associated species diversity (24 species across seven classes) after 1 year. Oyster recruitment was significantly influenced by depth for both oyster species but in opposite directions: M. gigas dominated at shallower depths, while O. angasi increasingly dominated with greater depth. Conclusions: Results demonstrate that shell gabion units can effectively facilitate native O. angasi recruitment at depths that limit non-native M. gigas while also generating positive biodiversity outcomes in a highly modified estuary.
School/Discipline
Dissertation Note
Provenance
Description
OnlinePubl
Access Status
Rights
© 2026 The Author(s). Restoration Ecology published by Wiley Periodicals LLC on behalf of Society for Ecological Restoration. This is an open access article under the terms of the Creative Commons Attribution- NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.