Body stoichiometry of heterotrophs: Assessing drivers of interspecific variations in elemental composition

Abstract

Aim The aim was to document how body stoichiometry of heterotrophs varies globally and to assess phylogenetic, trophic, habitat and body mass drivers of this interspecific variation in elemental composition, focusing on carbon (C), nitrogen (N) and phosphorus (P). Location World‐wide. Time period 1930–2019. Major taxa studied Amphibians, fishes (Actinopterygii), invertebrates, mammals, microbes and sauropsids (birds and reptiles). Methods We compiled from the scientific literature a global database of body elemental composition of heterotrophs in marine, freshwater and terrestrial realms. We used model selection and ANCOVAs to investigate the proportion of variance in elemental composition explained by taxonomic groups, diet, habitat and body mass. We assessed the phylogenetic signal in body stoichiometry using Blomberg's K and Pagel's λ statistics. We assessed the phylogenetic structure of interspecific variation in body stoichiometry using mixed models, with nested taxonomic levels as random factors. We finally assessed the covariations in elemental composition. Results Our database gathered 31,371 observations on 1,512 species. Body elemental composition was widely variable among species, with the four assessed drivers contributing significantly to this variation. Taxonomic group was the strongest contributor to interspecific variance for the stoichiometric traits studied, followed by habitat, diet and body mass. More precisely, C, N and P contents and C:N ratio were generally structured among classes, whereas the largest variations in C:P and N:P ratios were among families. This resulted in a significant but relatively modest phylogenetic signal. Finally, we found significant covariation among the three body elemental contents, resulting in taxonomic group‐specific C:N:P spectra. Main conclusions Our global synthesis of body stoichiometry of heterotrophs revealed a strong interspecific variability that was only modestly explained by the species attributes investigated (body mass, habitat and diet). It also revealed that this taxonomically structured residual variation in body stoichiometry seemed to be constrained along taxonomic group‐specific elemental spectra.

High dimensionality of stoichiometric niches in soil fauna

“…Our study provides new evidence for the MSN hypothesis by demonstrating large variation in body elemental contents and significant niche differentiation among nine soil animal taxa (Andrieux et al, 2021;Gonz alez et al, 2017). Variation in the body elemental content of soil animal taxa was partially (on average 53%) explained by phylogeny, consistent with recent findings in terrestrial plants (Andrieux et al, 2021), filter-feeding freshwater bivalves (Atkinson et al, 2020), and terrestrial and aquatic invertebrates (Gonz alez et al, 2011(Gonz alez et al, , 2018.…”

“…However, research has so far largely focused on the body contents of carbon (C), nitrogen (N), and phosphorus (P) of living organisms. Two recent studies used these three elements to distinguish different taxa and trophic groups in terrestrial and marine food webs (Andrieux et al, 2021;Gonz alez et al, 2017). However, research on terrestrial plants suggested that C, N, and P might not be sufficient to characterize the high-dimensional volume of MSNs and distinguish taxa effectively (Peñuelas et al, 2019;Sardans et al, 2021).…”

“…Soil biota play fundamental roles in regulating ecosystem processes, such as plant litter decomposition and nutrient mineralization (Bardgett & van der Putten, 2014). Despite their large amounts and essential roles in nutrient cycling, soil organisms are among the least understood groups of invertebrates in terms of MSN patterns (Andrieux et al, 2021;Maaroufi & De Long, 2020). Recent studies revealed that the biomass of various soil animal taxa is limited by distinct combinations of multiple elements in litter stoichiometry, including not only N and P but also calcium (Ca), sodium (Na), and sulfur (S) (Jochum et al, 2017;Kaspari & Yanoviak, 2009;Ott et al, 2014).…”

A database of West European headwater macroinvertebrate stoichiometric traits

“…Stoichiometric differences can also be found at finer taxonomic levels, for example among orders or families (results not shown), and have also been reported by other authors (González et al, 2018;Mehler et al, 2013;Morse et al, 2012). Besides these studies, Andrieux et al (2020) pointed out the importance of taxonomy in determining heterotrophs' stoichiometry.…”

Life stage and taxonomy the most important factors determining vertebrate stoichiometry: A meta‐analysis

“…Then, we scanned the citation list of each relevant study to identify papers missed by the systematic review. Our final data source was Andrieux et al ( 2021 ); we incorporated all unique values of whole‐body vertebrate %N, %P, and N:P available in their database. Although non peer‐reviewed zoo literature contained potentially relevant information, we did not include it due to methodological ambiguity (e.g.…”