Variations in ecosystem service provision of two functionally similar bivalve habitats

ABSTRACT

The quantification of ecosystem services (ES) remains challenging and can result in biases towards data-rich ES in management. For infaunal bivalves, little quantitative in situ data are available on the ES they provide, and differences between functionally similar species in different habitats are rarely considered. Here, we aimed to measure and compare the ecosystem functions (primary production, nutrient processing, water clearance rates) underpinning water quality regulation in an estuarine intertidal and subtidal bivalve habitat (dominated by Austrovenus stutchburyi and Paphies australis respectively). In situ benthic chambers were used to measure sediment–water column solute fluxes (NH₄⁺, N₂, O₂) and clearance rates which were scaled up (accounting for habitat differences; e.g. inundation period) to daily estimates of ES potential. Higher hourly microphytobenthic productivity, nitrogen recycling and water filtration were observed for the intertidal bivalve habitat. These differences were attributed to environmental differences rather than differences in bivalve biomass. However, scaling these rates to daily ES estimates showed that inundation period will restrict water quality regulating services in the intertidal. Measuring multiple ecosystem functions in situ provides an important step forward in ES quantification and accounts for ecological complexity, feedbacks and highlights habitat-specific differences in how functionally similar species contribute to ES.

KEYWORDS:

• Estuaries
• filtration
• nutrient cycling
• productivity
• water quality
• Tauranga harbour
• New Zealand

Acknowledgements

We would like to thank Dean Sandwell, David Culliford, Alice Morrison and Chris Morcom for technical support, Rebecca Gladstone-Gallagher, Emily Douglas, Steph Mangan, Georgina Flowers, Tarn Drylie, Kit Squires, Roger Colquhoun, Chris Dixon and Tomas van Elderen for fieldwork support, and Sarah Hailes and Barry Greenfield for help with macrofauna identification. This work was supported by the Ministry of Business, Innovation and Employment (MBIE; Contract No. C01X1515) as part of the Sustainable Seas National Science Challenge, Valuable Seas program, Project 2.1.3 ‘Measuring Ecosystem Services and Assessing Impacts’ (SUSS16202). VR wishes to acknowledge support for sample analysis provided by a University of Waikato ‘Faculty of Science and Engineering Student Trust Fund’ scholarship. We thank two anonymous reviewers for constructive comments that improved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author (VR), upon reasonable request.

Additional information

Funding

This work was supported by Ministry of Business, Innovation and Employment [Grant Number C01X1515].