Multidimensional trophic niche revealed by complementary approaches: gut content, digestive enzymes, fatty acids and stable isotopes in soil fauna

Abstract

15 1. The trophic niche of an organism is tightly related to its role in the ecosystem and can 16(2) described variation of these parameters in collembolan species, families and life 31 forms. 32 3. Correlation between trophic niche parameters of different methods was weak or absent in 33 45 out of 64 pairwise comparisons, reflecting that only some parameters provide similar 34 information. Gut content and fatty acids provided comparable information on fungivory 35 and plant feeding in Collembola. By contrast, information provided by digestive enzymes 36 differed from information gained by other methods, suggesting that digestive enzymes 37 3 had high additional value when combined with other methods. Stable isotope values were 38 related to parameters from other methods only when related to plant versus microbial 39 feeding. Many parameters were affected by family identity but not life form, suggesting 40 phylogenetic (taxonomic) signal in Collembola trophic niches. We highlighted the 41 additional value of method combination by providing a complex description of trophic 42 niches across families and showing emerging evidence that bacterial feeding in 43Collembola may be more common than it is often assumed. 44 4. Different methods estimate different feeding-related processes and thus different 45 dimensions of the trophic niche, being complementary rather than redundant. A 46 comprehensive picture of the trophic niche in complex food webs can be drawn by a 47 combination of different approaches. However, the number of studies that applied even 48 two methods simultaneously is very low in soil ecology. Controlled laboratory 49 experiments and description of field populations with several joint methodological 50 approaches is the way towards understanding of food-web functioning and coexistence of 51 species in cryptic environments. 52 53 Keywords 54 diet tracing, food webs, biomarkers, trophic interactions, springtails, method comparison 55 157 Ecology, 24(3), 247-261.

Trophic resources of the edaphic microarthropods: a worldwide review of the empirical evidence

“…The trophic resources used by soil microarthropods can be determined in a complementary way by using different methods (Potapov et al 2020;Walter, Kaplan, and Permar 1991) We found that a large proportion of the resources are defined as taxonomic categories of species, genera, and families, which would be important to estimate the diets of higher taxonomic groups. The available information for low taxonomic levels could be used as a reference to address the problem of what the use of soil resources will be like by higher level taxonomic groups (Bedano 2007).…”

“…Estimating the diet of organisms provides the foundation for understanding trophic interactions by characterizing how trophic resources are used by consumers within the soil ecosystem. Furthermore, it provides much-needed information on their trophic niches, their nutritional physiology, and the flows of matter and energy throughout the soil ecosystem (JM Nielsen et al 2018; Potapov et al 2020). The empirical characterization of trophic interactions is challenging due to the spatial and temporal complexity of feeding patterns, and the limitations of the methods to identify and quantify the components of the diet (JM Nielsen et al 2018; Pankhurst, Doube, and Gupta 1997; Walter, Kaplan, and Permar 1991).…”

“…The trophic resources used by soil microarthropods can be determined in a complementary way by using different methods (Potapov et al 2020; Walter, Kaplan, and Permar 1991). The most used resources are saprophytic fungi, nematodes, and bacteria.…”

Multidimensional trophic niche revealed by complementary approaches: Gut content, digestive enzymes, fatty acids and stable isotopes in Collembola

“…Raw data (Tables S1 –S4) supporting the results of the study are available from the Dryad Digital Repository https://doi.org/10.5061/dryad.gtht76hm6 (Potapov et al., 2021 ).…”

For flux's sake: General considerations for energy‐flux calculations in ecological communities

“…Whenever taking new measurements, we could, for example, make use of gut content analysis, digestive enzymes, fatty acids, and stable-isotope analysis or combine several of these analyses to identify a multidimensional trophic niche (Potapov et al, 2020).…”