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Identifying the interacting roles of stressors in driving the global loss of canopy-forming to mat-forming algae in marine ecosystems


Strain, EMA and Thomson, RJ and Micheli, F and Mancuso, FP and Airoldi, L, Identifying the interacting roles of stressors in driving the global loss of canopy-forming to mat-forming algae in marine ecosystems, Global Change Biology, 20, (11) pp. 3300-3312. ISSN 1354-1013 (2014) [Refereed Article]

Copyright Statement

Copyright 2014 John Wiley & Sons Ltd.

DOI: doi:10.1111/gcb.12619


Identifying the type and strength of interactions between local anthropogenic and other stressors can help to set achievable management targets for degraded marine ecosystems and support their resilience by identifying local actions. We undertook a meta-analysis, using data from 118 studies to test the hypothesis that ongoing global declines in the dominant habitat along temperate rocky coastlines, forests of canopy-forming algae and/or their replacement by mat-forming algae are driven by the nonadditive interactions between local anthropogenic stressors that can be addressed through management actions (fishing, heavy metal pollution, nutrient enrichment and high sediment loads) and other stressors (presence of competitors or grazers, removal of canopy algae, limiting or excessive light, low or high salinity, increasing temperature, high wave exposure and high UV or CO2), not as easily amenable to management actions. In general, the cumulative effects of local anthropogenic and other stressors had negative effects on the growth and survival of canopy-forming algae. Conversely, the growth or survival of mat-forming algae was either unaffected or significantly enhanced by the same pairs of stressors. Contrary to our predictions, the majority of interactions between stressors were additive. There were however synergistic interactions between nutrient enrichment and heavy metals, the presence of competitors, low light and increasing temperature, leading to amplified negative effects on canopy-forming algae. There were also synergistic interactions between nutrient enrichment and increasing CO2 and temperature leading to amplified positive effects on mat-forming algae. Our review of the current literature shows that management of nutrient levels, rather than fishing, heavy metal pollution or high sediment loads, would provide the greatest opportunity for preventing the shift from canopy to mat-forming algae, particularly in enclosed bays or estuaries because of the higher prevalence of synergistic interactions between nutrient enrichment with other local and global stressors, and as such it should be prioritized.

Item Details

Item Type:Refereed Article
Keywords:anthropogenic stressors, canopy-forming algae, habitat shifts, management, mat-forming algae
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Coastal and estuarine systems and management
Objective Field:Assessment and management of coastal and estuarine ecosystems
UTAS Author:Strain, EMA (Dr Beth Strain)
UTAS Author:Thomson, RJ (Miss Rebecca Thomson)
ID Code:98886
Year Published:2014
Web of Science® Times Cited:148
Deposited By:IMAS Research and Education Centre
Deposited On:2015-03-05
Last Modified:2021-09-22

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