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Low redundancy and complementarity shape ecosystem functioning in a low-diversity ecosystem

journal contribution
posted on 30.03.2020, 00:00 by CJ Henderson, BL Gilby, TA Schlacher, RM Connolly, M Sheaves, PS Maxwell, Nicole FlintNicole Flint, HP Borland, TSH Martin, AD Olds
Ecosystem functioning is positively linked to biodiversity on land and in the sea. In high-diversity systems (e.g. coral reefs), species coexist by sharing resources and providing similar functions at different temporal or spatial scales. How species combine to deliver the ecological function they provide is pivotal for maintaining the structure, functioning and resilience of some ecosystems, but the significance of this is rarely examined in low-diversity systems such as estuaries. We tested whether an ecological function is shaped by biodiversity in a low-diversity ecosystem by measuring the consumption of carrion by estuarine scavengers. Carrion (e.g. decaying animal flesh) is opportunistically fed on by a large number of species across numerous ecosystems. Estuaries were chosen as the model system because carrion consumption is a pivotal ecological function in coastal seascapes, and estuaries are thought to support diverse scavenger assemblages, which are modified by changes in water quality and the urbanization of estuarine shorelines. We used baited underwater video arrays to record scavengers and measure the rate at which carrion was consumed by fish in 39 estuaries across 1,000 km of coastline in eastern Australia. Carrion consumption was positively correlated with the abundance of only one species, yellowfin bream Acanthopagrus australis, which consumed 58% of all deployed carrion. The consumption of carrion by yellowfin bream was greatest in urban estuaries with moderately hardened shorelines (20%–60%) and relatively large subtidal rock bars (>0.1 km2). Our findings demonstrate that an ecological function can be maintained across estuarine seascapes despite both limited redundancy (i.e. dominated by one species) and complementarity (i.e. there is no spatial context where the function is delivered significantly when yellowfin bream are not present) in the functional traits of animal assemblages. The continued functioning of estuaries, and other low-diversity ecosystems, might therefore not be tightly linked to biodiversity, and we suggest that the preservation of functionally dominant species that maintain functions in these systems could help to improve conservation outcomes for coastal seascapes.© 2019 British Ecological Society

Funding

Category 2 - Other Public Sector Grants Category

History

Volume

89

Issue

3

Start Page

784

End Page

794

Number of Pages

11

eISSN

1365-2656

Publisher

Wiley-Blackwell Publishing, UK

Peer Reviewed

Yes

Open Access

No

Acceptance Date

17/10/2019

External Author Affiliations

Healthy Land and Water, Qld.; University of the Sunshine Coast; Griffith University; James Cook University

Author Research Institute

Coastal Marine Ecosystems Research Centre (CMERC)

Era Eligible

Yes

Journal

Journal of Animal Ecology