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.
Highlights
In the last decades, numerous observations have greatly advanced our understanding of how large amounts of labile substances are released from plant litter during the early stage of decomposition [1,2].Empirical evidence suggests that these soluble compounds, such as dissolved organic carbon (DOC)and total dissolved nitrogen (TDN), are primarily released from freshly shed litter through hydrological leaching accompanied by rainfall or snow melt [3] and move into the soil horizon or aquatic ecosystems [4]
Versini et al demonstrated that the low DOC and TDN concentrations derived from fresh litter can percolate deep into mineral soil [6]
Totals of 37, 140 and 222 individuals of soil fauna were observed in the arid valley, ecotone and subalpine forest, respectively, during the entire study period (Table 2)
Summary
Numerous observations have greatly advanced our understanding of how large amounts of labile substances are released from plant litter during the early stage of decomposition [1,2].Empirical evidence suggests that these soluble compounds, such as dissolved organic carbon (DOC)and total dissolved nitrogen (TDN), are primarily released from freshly shed litter through hydrological leaching accompanied by rainfall or snow melt [3] and move into the soil horizon or aquatic ecosystems [4]. Fröberg et al found that large amounts of litter-derived DOC were retained and consumed on the soil surface without being transferred into the mineral soils [5]. Versini et al demonstrated that the low DOC and TDN concentrations derived from fresh litter can percolate deep into mineral soil [6]. These findings imply that dissolved carbon and nitrogen are important sources of carbon and nutrients for soil decomposers and may be quickly assimilated by soil organisms living on the litter surface [4,7] because of the low molecular weight of the litter leachates [8]. Information regarding how soil fauna contribute to the release of dissolved carbon and nitrogen from plant litter is limited
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
