Water, Rather than Temperature, Dominantly Impacts How Soil Fauna Affect Dissolved Carbon and Nitrogen Release from Fresh Litter during Early Litter Decomposition

Abstract

Abstract:Longstanding observations suggest that dissolved materials are lost from fresh litter through leaching, but the role of soil fauna in controlling this process has been poorly documented. In this study, a litterbag experiment employing litterbags with different mesh sizes (3 mm to permit soil fauna access and 0.04 mm to exclude fauna access) was conducted in three habitats (arid valley, ecotone and subalpine forest) with changes in climate and vegetation types to evaluate the effects of soil fauna on the concentrations of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) during the first year of decomposition. The results showed that the individual density and community abundance of soil fauna greatly varied among these habitats, but Prostigmata, Isotomidae and Oribatida were the dominant soil invertebrates. At the end of the experiment, the mass remaining of foliar litter ranged from 58% for shrub litter to 77% for birch litter, and the DOC and TDN concentrations decreased to 54%-85% and increased to 34%-269%, respectively, when soil fauna were not present. The effects of soil fauna on the concentrations of both DOC and TDN in foliar litter were greater in the subalpine forest (wetter but colder) during the winter and in the arid valley (warmer but drier) during the growing season, and this effect was positively correlated with water content. Moreover, the effects of fauna on DOC and TDN concentrations were greater for high-quality litter and were related to the C/N ratio. These results suggest that water, rather than temperature, dominates how fauna affect the release of dissolved substances from fresh litter.

Synergistic effects: a common theme in mixed‐species litter decomposition

“…This study is primarily dedicated to calculate the general effects of litter mixture on its decay rates. Our results showed that the litter mixture widely demonstrates a non-additive effect, and most frequently synergistic effect, which is consistent with two previous review studies (Gartner & Cardon 2004;Li et al, 2016). Specifically, the decay rates of litter mixture are on average 2%-4% faster when compared to that of single litter species (Fig.…”

“…Although experiments concerning the mixture effects on litter decomposition rates have been conducted in numerous individual studies, the conflicting results have hampered any possibility to draw general conclusions (Li et al, 2016). Most of conflicts could mainly result from the significant differences of influencing factors related to litter decompositions in experimental design (Barbe et al 2018, Leroy et al 2018, Zhao et al 2019.…”

“…While studies throughout the literature have summarized and analyzed the non-additive effect in mixed litter decomposition (Gartner & Cardon, 2004;Li et al, 2016), there still remains a lot of unanswered questions. In order to better understand how the mixing influences the decomposition rate of litter, we employed a meta-analysis that built upon the system analysis done by Gartner and Cardon (2004).…”

Synergistic effect: a common theme in mixed-species litter decomposition

“…In the early decomposition stages, fresh litter input provides abundant food for the soil fauna and microorganisms. In addition, studies suggest that nutrient transport often occurs in the early decay stages (Hansson et al, 2010;Liao et al, 2016). Thus, the abundant food and efficient nutrient transport facilitate growth and activity of soil microorganisms, which ultimately produce a synergistic effect.…”

Effect of Soil Fauna on Home-Field Advantages of Litter Mass Loss and Nutrient Release in Different Temperate Broad-Leaved Forests

“…In addition, the specialization of soil fauna require favorable environmental factors, such as illumination, temperature, and moisture, which lead to differences in the HFA. Water, rather than temperature, impacts the effects of fauna on the carbon and nitrogen release from fresh litters during early litter decomposition [19]. For the HFA, the linkages between litter mass loss, nutrient release, and the soil's faunal community are not fully understood in temperate forest ecosystems.…”