Functional redundancy and specific taxa modulate the contribution of prokaryotic diversity and composition to multifunctionality

Abstract

Observational and experimental evidence has revealed the functional importance of microbial diversity. However, the effects of microbial diversity loss on ecosystem functions are not consistent across studies, which are probably tempered by microbial functional redundancy, specific taxa and functions evaluated. Here we conducted diversity manipulation experiments in two independent soils with distinct prokaryotic communities, and investigated how the initial community traits (e.g., distinct functional redundancy and taxonomic composition) modulate the contribution of prokaryotic diversity loss and composition shift to eight ecosystem functions related to soil nutrient cycling. We found that diversity loss impaired three functions (potential nitrification rate, N2‐fixation activity and phosphatase) and multifunctionality only in the communities with low functional redundancy, but all examined functions were unaffected in the communities with high functional redundancy. All significantly affected functions belonged to specialized functions, while the broad function (soil basal respiration) was unaffected. Moreover, prokaryotic composition explained more functional variation than diversity, which was ascribed to the crucial role of specific taxa that influence particular functions. Taken together, this study provides empirical evidence for identifying the mechanism underlying the ecosystem response to changes in microbial community, with implications for improving the prediction of ecosystem process models and managing microbial communities to promote ecosystem services.

Multiple anthropogenic pressures eliminate the effects of soil microbial diversity on ecosystem functions in experimental microcosms

“…Moreover, the relative abundance of some rare soil bacteria 33 , e.g., Chloroflexia, Gemmatimonadetes, Longimicrobia, Myxococcia, Planctomycetes, was correlated with the reduction of soil functions along with an increasing number of GCFs, probably because GCFs are likely more detrimental for rare microbial species than common species 15 . Our results are consistent with previous studies showing that specific microbial taxa are important for soil functions 34 , 35 . The presence of productive species is a major determinant of the effect of plant diversity on productivity, known as the selection effect 36 .…”

Faunal communities mediate the effects of plant richness, drought, and invasion on ecosystem multifunctional stability

“…Community stability matters for regulating multifunctional stability. It has been recognized that the composition of communities across the food web play determining roles in regulating the dynamics of various ecosystem functions 38 , 40 , 41 . Deeper insights have also been given into the common linkage between ecosystem multifunctional stability and the composition, or more specifically, the compositional stability of communities 3 , 38 , 42 .…”

“…Community composition has been suggested to play an even more important role than biodiversity per se in driving the dynamics of multiple ecosystem functions 40 , 41 , 57 , 58 , and this lays the basis for the logic that models of plant richness-multifunctional stability relationship may be improved by incorporating the compositional traits (e.g., stability) of communities across the food web. Our results based on SEMs showed the positive indirect effects of plant richness on multifunctional stability by increasing the stability of plant, litter-, and soil-faunal communities (Figs.…”

Plant diversity improves resistance of plant biomass and soil microbial communities to drought

“…We also determined the activity of five key soil enzymes involved in soil nutrient cycling, including oxidoreductase (dehydrogenase and nitrate reductase) and hydrolase (β‐glucosidase, protease and urease). The enzyme activities can be a good proxy of soil functions as these key enzymes play a direct role in soil mineralization and nutrient availability (Garland et al, 2021; Li et al, 2021; Trivedi et al, 2016). The activity of soil enzymes, including dehydrogenase, nitrate reductase, β‐glucosidase, protease and urease, was determined with the spectrophotometric method using the specific substrates, including triphenyltetrazolium chloride (TTC; Singh & Singh, 2005), nitrate (Seth & Misra, 2014), salicin (Han & Chen, 2008), caseinate (Ge et al, 2012) and urea (Kandeler & Gerber, 1988).…”

“…We also determined the activity of five key soil enzymes involved in soil nutrient cycling, including oxidoreductase (dehydrogenase and nitrate reductase) and hydrolase (β-glucosidase, protease and urease). The enzyme activities can be a good proxy of soil functions as these key enzymes play a direct role in soil mineralization and nutrient availability (Garland et al, 2021;Li et al, 2021;Trivedi et al, 2016).…”