The function-dominance correlation drives the direction and strength of biodiversity-ecosystem functioning relationships

Abstract

Community composition is a primary determinant of how biodiversity change influences ecosystem functioning and, therefore, the relationship between biodiversity and ecosystem functioning (BEF). We examine the consequences of community composition across six structurally realistic plant community models. We find that a positive correlation between species’ functioning in monoculture vs. their dominance in mixture with regards to a specific function (the “function-dominance correlation”) generates a positive relationship between realized diversity and ecosystem functioning across species richness treatments. However, because realised diversity declines when few species dominate, a positive function-dominance correlation generates a negative relationship between realized diversity and ecosystem functioning within species richness treatments. Removing seed inflow strengthens the link between the function-dominance correlation and BEF relationships across species richness treatments but weakens it within them. These results suggest that changes in species’ identities in a local species pool may more strongly affect ecosystem functioning than changes in species richness.

Linking changes in species composition and biomass in a globally distributed grassland experiment

“…Additionally, some variation in site‐level responses may be due to water limitation, and may account for some cases where nutrients do not affect biomass in very high and very low ends of the precipitation gradient represented here (Figure S11). Additional mechanisms driving patterns within and across sites (Figure S11) (Avolio et al, 2021), spatial scales (Barry et al, 2021; Chase et al, 2019; Seabloom et al, 2021) and according to species' functional identities and characteristics (Crawford et al, 2021) could also be further investigated. We now know that the risk of a species being lost from a plot decreases with its abundance and varies across functional forms (Wilfahrt et al, 2021).…”

Multitrophic diversity and biotic associations influence subalpine forest ecosystem multifunctionality

“…However, we found a negative or negligible relationship between species richness and multifunctionality for most trophic groups at neighborhood scales, a result that is inconsistent with previous studies (Wang et al, 2019). One plausible reason for this surprising finding is that competitive, though low‐functioning, species are more likely to be incorporated into diverse mixtures, and this will lead to a tendency of species‐rich communities to provide little functionality (Crawford et al, 2021). Thus, species' identities in a local species pool may more strongly affect ecosystem multifunctionality than changes in species richness at a small scale (Crawford et al, 2021; Hagan et al, 2021).…”

“…One plausible reason for this surprising finding is that competitive, though low‐functioning, species are more likely to be incorporated into diverse mixtures, and this will lead to a tendency of species‐rich communities to provide little functionality (Crawford et al, 2021). Thus, species' identities in a local species pool may more strongly affect ecosystem multifunctionality than changes in species richness at a small scale (Crawford et al, 2021; Hagan et al, 2021). A second reason for this scale effect could be that resource and abiotic variables are sufficiently homogeneous at small scales, so there are insufficient opportunities for niche partitioning and complementarity, and, thus, the best performing species that are well matched to local conditions determine ecosystem function (Cardinale, 2011), but the strong environmental gradient means that spillover of less fit species might dilute functional efficiency.…”