Biodiversity increases functional and compositional resistance, but decreases resilience in phytoplankton communities

Abstract

There is now ample evidence that biodiversity stabilizes aggregated ecosystem functions, such as primary production, in changing environments. In primary producer systems, this stabilizing effect is found to be driven by higher functional resistance (i.e., reduced changes in functions by environmental changes) rather than through higher functional resilience (i.e., rapid recovery following environmental changes) in more diverse systems. The stability of aggregated ecosystem functions directly depends on changes in species composition and by consequence their functional contributions to ecosystem functions. Still, it remains only theoretically explored how biodiversity can stabilize ecosystem functions by affecting compositional stability. Here, we demonstrate how biodiversity effects on compositional stability drive biodiversity effects on functional stability in diatom communities. In a microcosm experiment, we exposed 39 communities of five different levels of species richness (1, 2, 4, 6, and 8 species) to three concentrations of a chemical stressor (0, 25, and 250 μg/L atrazine) for four weeks, after which all communities were transferred to atrazine-free medium for three more weeks. Biodiversity simultaneously increased, increasing functional and compositional resistance, but decreased functional and compositional resilience. These results confirm the theoretically proposed link between biodiversity effects on functional and compositional stability in primary producer systems, and provide a mechanistic underpinning for observed biodiversity-stability relationships. Finally, we discuss how higher compositional stability can be expected to become increasingly important in stabilizing ecosystem functions under field conditions when multiple environmental stressors fluctuate simultaneously.

Decomposing multiple dimensions of stability in global change experiments

“…Although the conceptual framework for such trait‐based analyses of multiple dimensions of stability has been laid out, few empirical analyses show the feasibility of an approach addressing species contributions to community‐level stability (Supp & Ernest ; Baert et al . ).…”

“…Such a trait-stability relationship would mirror the trait-functioning relationships which have been established to explain biodiversity effects on ecosystem functions such as productivity (Reiss et al 2009;Loreau 2010). Although the conceptual framework for such trait-based analyses of multiple dimensions of stability has been laid out, few empirical analyses show the feasibility of an approach addressing species contributions to communitylevel stability (Supp & Ernest 2014;Baert et al 2016).…”

The dimensionality of stability depends on disturbance type

“…For such experiments the use of modelling studies, as done here, seems a useful way forward, because collection of such data empirically is feasible only in micro‐ and mesocosm settings (Baert et al . 2016b; Garnier et al . ; Karakoç et al .…”

Livestock grazing regulates ecosystem multifunctionality in semi‐arid grassland

“…Grazing-induced changes in plant functional traits can be particularly important in understanding ecosystem multifunctionality. High grazing pressure has been shown to reduce functional diversity (FD) (Baert, De Laender, Sabbe, & Janssen, 2016;Gross, Suding, Lavorel, & Roumet, 2007;Gross et al, 2014;Li et al, 2017). Relatively high FD may benefit an ecosystem by enhancing plant community complementarity in resource acquisition and utilization and promoting community resilience and resistance.…”