Aboveground Herbivory Shapes the Biomass Distribution and Flux of Soil Invertebrates

Abstract

BackgroundLiving soil invertebrates provide a universal currency for quality that integrates physical and chemical variables with biogeography as the invertebrates reflect their habitat and most ecological changes occurring therein. The specific goal was the identification of “reference” states for soil sustainability and ecosystem functioning in grazed vs. ungrazed sites.Methodology/Principal FindingsBacterial cells were counted by fluorescent staining and combined direct microscopy and automatic image analysis; invertebrates (nematodes, mites, insects, oligochaetes) were sampled and their body size measured individually to allow allometric scaling. Numerical allometry analyses food webs by a direct comparison of weight averages of components and thus might characterize the detrital soil food webs of our 135 sites regardless of taxonomy. Sharp differences in the frequency distributions are shown. Overall higher biomasses of invertebrates occur in grasslands, and all larger soil organisms differed remarkably.Conclusions/SignificanceStrong statistical evidence supports a hypothesis explaining from an allometric perspective how the faunal biomass distribution and the energetic flux are affected by livestock, nutrient availability and land use. Our aim is to propose faunal biomass flux and biomass distribution as quantitative descriptors of soil community composition and function, and to illustrate the application of these allometric indicators to soil systems.

Soil acidity, ecological stoichiometry and allometric scaling in grassland food webs

“…All values were averaged over the life-stages of all the counted individuals N (Mulder et al , 2005a,b;). These body-mass averages at genus level offer the best available combination of high environmental information and low noise (Mulder et al , 2006, 2008). …”

Application of body size spectra to nematode trait-index analyses

“…Several studies of soil systems have used BSS as a predictor or response metric of community change in relation to environmental disturbance for soil microbes and microfauna (Mulder et al, 2008;Mulder and Elser, 2009), mesofauna (i.e. mites and Collembola) (Lindo et al, 2012;Turnbull and Lindo, 2015), or macro-arthropods (Hocking et al, 2013), but there has been no previous attempt to link BSS to the indicator roles of soil nematode communities.…”

World Wide Food Webs: Power to Feed Ecologists

“…Although there is meanwhile a general agreement that, at population level, the body-mass average remains a statistically reliable predictor of the numerical abundance in food webs (Fig. 1), it is not the identification of any universal structure, but the full mechanistic explanation of structural variations beyond which is challenging (Mulder et al 2005(Mulder et al , 2008. Such results become even more interesting if seen in the dynamic framework of interspecific competition: different sensitivity to the elemental resources allows to understand better population dynamics and to increase the realism of extrapolations.…”