Relative Contributions of Biodiversity and Environment to Benthic Ecosystem Functioning

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 indicate 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.

Exploring the Relationship between Macrofaunal Biodiversity and Ecosystem Functioning in the Deep Sea

“…The number of deposit feeders was included, because they were the most numerous trophic group in our macrofauna samples, and deposit feeding is one of the most effective feeding strategies in environments with generally meager food sources, such as the deep sea (Gage and Tyler, 1991). Bioturbation activity on and in the seafloor, is closely related to the way organisms feed and move (Welsh, 2003) and it is assumed to have an influence on benthic processes (Belly and Snelgrove, 2016). Indeed, we considered the macrofaunal bioturbation activity to be an important functional trait.…”

“…Belly and Snelgrove (2016) showed how macrofaunal functional diversity and environmental variables can equally explain the majority of variability in some key ecosystem processes. Most deep-sea communities are usually food-limited ( Levin et al, 2001), and their reliance on the relatively small input of organic carbon from the surface and the particulate organic carbon flux are held to exert a strong influence on deep-sea biodiversity (Tittensor et al, 2011) and ecosystem function (Smith et al, 2008).…”

Template for using biological trait groupings when exploring large‐scale variation in seafloor multifunctionality

“…Still, even in open waters, the functions provided by the benthic communities have proven to be important from an ecosystem perspective (e.g., Norkko et al. , Belley and Snelgrove ). Consequently, we argue that these properties are essential for sustaining ecosystem functions and services in disturbance‐prone coastal areas, as exemplified in this study by focusing on the Baltic Sea.…”

“…Especially in shallow coastal and estuarine areas, where the benthic and pelagic realm are intimately linked, the considered properties are important for the functioning of the entire ecosystem (Kristensen et al 2014, Griffiths et al 2017. Still, even in open waters, the functions provided by the benthic communities have proven to be important from an ecosystem perspective (e.g., Norkko et al 2015, Belley andSnelgrove 2016). Consequently, we argue that these properties are essential for sustaining ecosystem functions and services in disturbance-prone coastal areas, as exemplified in this study by focusing on the Baltic Sea.…”

Is the trophic diversity of marine benthic consumers decoupled from taxonomic and functional trait diversity? Isotopic niches of Arctic communities

“…It is increasingly recognized that a suite of functional traits determines community functioning better than the mere number of species (Hooper et al 2005;Deraison et al 2015). Functional trait diversity has been documented to have stronger effect than species richness on, e.g., benthic oxygen fluxes in marine sediments (Belley and Snelgrove 2016) or the productivity of rock pool macroalgae (Griffin et al 2009). Furthermore, evidence suggests that species richness and functional diversity may even have different effects on community function in terms of biomass accumulation and productivity (Reich et al 2004).…”