CONTRIBUTION OF SOIL SAPROPHAGES TO ECOSYSTEM PROCESSES DEPENDS ON THEIR ABUNDANCE AND TOTAL METABOLISM: RESULTS OF A COMPREHENSIVE FIELD EXPERIMENT ACROSS A WIDE CLIMATIC GRADIENT
Sotnikov I., Tiunov A.
RJEE Vol. 11 (2). 2026 | DOI: 10.21685/2500-0578-2026-2-3
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Receipt date 11.02.2026 | Publication date 26.06.2026
CONTRIBUTION OF SOIL SAPROPHAGES TO ECOSYSTEM PROCESSES DEPENDS ON THEIR ABUNDANCE AND TOTAL METABOLISM. RESULTS OF A COMPREHENSIVE FIELD EXPERIMENT ACROSS A WIDE CLIMATIC GRADIENT
I.V. Sotnikov1, A.V. Tiunov2
1, 2 A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia
1 vania.sotnikov@ya.ru
Abstract. Soil macro-saprophages are a key component of ecosystems, regulating the rates of biogeochemical cycles and physically transforming the soil environment. Current understanding of the functional role of soil macrofauna at the global scale is based mainly either on “binary” experiments (presence or absence of animals in litterbags) or on extrapolation of laboratory estimates of trophic or burrowing activity to natural ecosystems. Direct comparisons between the abundance of soil saprophages and their functional activity are scarce and mostly limited to local studies. In this study, for the first time, we conducted a comprehensive set of field experiments simultaneously assessing the abundance and metabolism of invertebrates together with their trophic and bioturbation activity. The study was carried out in 10 ecosystems across a wide climatic gradient, from mountain tundra to tropical rainforest. The total metabolism of macro-saprophages strongly correlated with both trophic activity (bait lamina test, R² = 0.73) and fauna-mediated litter decomposition (R² = 0.60). The strong linear relationship between the two methods (R² = 0.52) suggests that the bait lamina test can be used for rapid assessment of the contribution of saprophages to litter decomposition. In addition, we developed a novel field method for estimating the intensity of soil profile bioturbation using tracer particles and demonstrated that the rate of glass bead incorporation into the soil was strongly correlated (R² = 0.44) with earthworm activity (i.e., temperature-corrected abundance). However, the abundance or metabolism of macro-saprophages had only a weak effect on the distribution of δ13С and δ15N values within the soil profile. Because invertebrate activity depends strongly on temperature, using metabolism or other measures of animal activity much better predicts the contribution of saprophages to ecosystem processes than their density or biomass. Our findings demonstrate the potential for using data on the abundance and community composition of soil invertebrates to estimate their contribution to key ecosystem processes associated with plant litter decomposition and soil profile formation.
Keywords: ecosystem functions, soil biota, ecosystem engineers, trophic activity, bioturbation, soil isotope profile, field experiments, functiometer
Acknowledgement: we express our deep gratitude to D.D. Vinogradov, K.V. Savelieva, O.L. Rozanova, A.V. Kolotei, A.O. Zvezdin, as well as to F.A. Plandin, I.D. Tsvelev, A.A. Kudrin and I.G. Dovgobrod for their assistance in conducting fieldwork. We thank S.M. Tsurikov for performing the isotope analysis of the soil and L.B. Rybalov for his help in identifying invertebrates. We also express our gratitude to the staff of the N.A. Avrorin Polar‑Alpine Botanical Garden – E.A. Borovichev and E.I. Kopeina – for the opportunity to carry out research at the mountain tundra sites. We also thank the Joint Russian‑Vietnamese Tropical Research and Technology Centre of the Institute of Ecology and Evolution of the Russian Academy of Sciences for the opportunity to conduct research in the territories of Bidoup‑Nui Ba and Cat Tien National Parks.
Financing: the work was carried out within the framework of the topic FFER‑2024‑0024 of the State Assignment of the Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS).
For citation: Sotnikov I.V., Tiunov A.V. Contribution of soil saprophages to ecosystem processes depends on their abundance and total metabolism. Results of a comprehensive field experiment across a wide climatic gradient. Russian Journal of Ecosystem Ecology. 2026;11(2). (In Russ.). Available from: https://doi.org/ 10.21685/2500-0578-2026-2-3