Biodiversity ecosystem functioning research in freshwater phytoplankton: A comprehensive review of trait-based studies

Abstract

In an effort to reach a clearer mechanistic understanding of the influence of biological diversity on ecosystem functioning, research in the field is increasingly applying a trait-based approach. In this comprehensive review, I searched for and analyzed studies that focused on the relationship between biodiversity and ecosystem functioning (BEF) using a trait-based approach in freshwater phytoplankton from lentic systems (lakes, ponds, reservoirs). I found that this type of studies is very rare and included a plethora of traits, diversity metrics, statistical analyses and study locations that contributed to the high variability in the results they obtained. Overall, trait-based diversity is not a very good predictor of ecosystem functioning in freshwater lentic ecosystems. Null relationships between trait-based diversity and ecosystem functioning in freshwater lentic systems were the more frequent outcome. When significant, the amount of variation in ecosystem functioning explained by trait-based diversity was small. Still, trait-based research remains a promising approach to increase the mechanistic understanding of BEF relationships. For this purpose, studies directly testing the underlying mechanistic rationale, exploring diversity effects on the temporal stability of ecosystem functions, including multiple functions at a time, focusing more in cell size and shape and confirming the relative importance of individual trait variation for ecosystem functioning are needed.

Why are biodiversity—ecosystem functioning relationships so elusive? Trophic interactions may amplify ecosystem function variability

“…Mouquet et al, 2002; Seibold et al, 2018). Such complexity in the BEF relationship has been attributed to a rich array of factors, including disparate definitions of diversity and functions (Hooper et al, 2005), spatial heterogeneity (Griffin et al, 2009), environmental context (Hong et al, 2022; Ratcliffe et al, 2017), species traits (Strong et al, 2015; Venail, 2017) and trophic structure (Wang & Brose, 2018). For example, experimental studies have demonstrated that the presence of herbivores can largely alter the positive relationship between grassland species diversity and plant biomass by altering plant species composition via top‐down control (Mulder et al, 1999; Seabloom et al, 2017).…”

Freshwater phytoplankton diversity: models, drivers and implications for ecosystem properties

“…The use of FD components in the context of BEF in phytoplankton has only started very recently (Abonyi et al, 2018a, b;Ye et al, 2019). Trait-based functional diversity measures in BEF have recently been reviewed by Venail (2017).…”

“…The wellknown paradox of Hutchinson asking how so many species may coexist in phytoplankton (Hutchinson, 1961) has been reversed to how many species ensure ecosystem functioning (Ptacnik et al, 2010b). Based on functional traits, however, almost half of the studies reported null or negative relationship between functional diversity and ecosystem functioning (Venail, 2017). Recently, Abonyi et al (2018a, b) argued that functional diversity based on trait categories (i.e., functional trait richness-FTR) and Reynolds' ecological groups (i.e., functional group richness-FGR) represented different aspects of community organisation in phytoplankton.…”