Relative Contributions of Biodiversity and Environment to Benthic Ecosystem Functioning

Rénald Belley,Paul V. R. Snelgrove

doi:10.3389/fmars.2016.00242

Rénald Belley, Paul V. R. Snelgrove

Open Access

https://doi.org/10.3389/fmars.2016.00242

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Abstract

Current concern about biodiversity change associated with human impacts has raised scientific interest in the role of biodiversity in ecosystem functioning. However, studies on this topic face the challenge of evaluating and separating the relative contributions of biodiversity and environment to ecosystem functioning in natural environments. To investigate this problem, we collected sediment cores at different seafloor locations in Saanich Inlet and the Strait of Georgia, British Columbia, Canada, and measured benthic fluxes of oxygen and five nutrients (ammonium, nitrate, nitrite, phosphate and silicate). We also measured 18 environmental variables at each location, identified macrofauna, and calculated a suite of species and functional diversity indices. Our results indicated that, examined separately, macrobenthic functional richness (FRic) predicted benthic flux better than species richness, explaining ~ 20% of the benthic flux variation at our sites. Environmental variables and functional diversity indices collectively explained 62.9% of benthic flux variation, with similar explanatory contributions from environmental variables (21.4%) and functional diversity indices (18.5%). The 22.9% shared variation between environmental variables and functional diversity indices demonstrate close linkages between species and environment. Finally, we also identified funnel feeding as a key functional group represented by a small number of species and individuals of maldanid and pectinariid polychaetes, which disproportionately affected benthic flux rates relative to their abundance. Our results indicate the primary importance of environment and functional diversity in controlling ecosystem functioning. Furthermore, these results illustrate the consequences of anthropogenic impacts, such as biodiversity loss and environmental changes, for ecosystem functioning.

Highlights

The loss of biodiversity and its impact on humanity (Cardinale et al, 2012) have raised considerable interest on potential links between biodiversity and ecosystem functioning in a wide range of ecosystems (Loreau et al, 2001, 2002; Solan et al, 2004; Loreau, 2010)
Our study indicates that environmental variables and functional diversity indices we measured explain the majority of flux variation in our Salish Sea sedimentary sites
Microbial abundance, benthic macrofaunal functional richness, and indices related to bioturbation and bio-irrigation were the most important variables in explaining benthic flux variation and organic matter remineralization at our seafloor study sites

Summary

Introduction

The loss of biodiversity and its impact on humanity (Cardinale et al, 2012) have raised considerable interest on potential links between biodiversity and ecosystem functioning in a wide range of ecosystems (Loreau et al, 2001, 2002; Solan et al, 2004; Loreau, 2010). This work points to a strong role for functional groups in controlling ecosystem functions (Hooper et al, 2005; Cardinale et al, 2006; Danovaro et al, 2008) and a potential role for environment (Yachi and Loreau, 1999; Godbold and Solan, 2009; Belley et al, 2016). Most of these studies focus on biodiversity loss by manipulating species in experiments (Cardinale et al, 2012; Naeem et al, 2012), natural. Studies that have tried to separate abiotic and biotic contributions generally found that both played an important role (Hiddink et al, 2009; Queirós et al, 2011; Godbold, 2012; Braeckman et al, 2014; Strong et al, 2015)

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