- (a) Tree species richness and identity effects on ground ecosystem functions (hypotheses i and ii), 1,440 observations. (b) Tree species richness effects on the spatial stability of soil ecosystem functions (hypothesis iii), dos88 observations. (c) Tree species richness effects on the temporal stability of soil ecosystem functions (hypothesis iv), 24 observations. (d) General relationship between spatial stability and temporal stability of soil ecosystem functions (hypothesis v), 24 observations. Up arrows (^) indicate significant positive effect, down arrows (v) indicate significant negative effect. Significant fixed effects (P < 0.05) are shown boldface type.
- * P < 0.05, ** P < 0.01, *** P < 0.001.
Separate linear mixed-effects models were used to test the effect of tree species richness (TSR; as a fixed factor) and tree species identity (type of plot as fixed factor with seven levels: ash monoculture, beech monoculture, linden monoculture, oak monoculture, pine monoculture, spruce monoculture, and five-species mixture) on soil basal respiration (BR), soil microbial biomass (Cmic), soil water content (H2OSoil), tea mass loss (TML), and soil-surface temperature (Tempsoil).
A statistical notation of your own habits (based on Gelman and you can Mountain ( 2007 )) are in Appendix S1: Section S4).
Spatial and temporal stability
To test the outcome regarding forest varieties richness towards spatial stability regarding crushed ecosystem properties, i utilized a beneficial linear combined-consequences model structure analogue into design mentioned getting general BEF dating, because of the replacing ecosystem characteristics and you can attributes with the spatial balances.
Temporary balances regarding ground ecosystem features over-all sampling incidents is actually computed as inverse of Cv in the area level situated into mediocre processes speed for each area for every single sampling skills. We picked this method to choose spatial and temporary balance to help you create comparable results to earlier education that have checked these stability steps primarily for the isolation. not, this method is regarded as asymmetric, just like the spatial balance is computed toward area peak each sampling experience while the inverse of coefficient away from version, when you are temporal balance out of surface environment characteristics over-all sampling situations try determined given that inverse away from Cv during the plot top. We recognized this variation, because the soil bacterial services in addition to their temporal dynamics are typically calculated from the taking a look at majority crushed examples of multiple floor cores per plot so you can take into account certain possible spatial heterogeneity during the respective patch (e.g., Gregorich 2007 , Eisenhauer ainsi que al. 2010 , Tedersoo mais aussi al. 2014 ). Delivering and analyzing short, individual ground cores to evaluate surface variables may not be regarded as suitable so you’re able to represent a land well and thus not complete. This relates to date collection analyses of such plot-particular analysis (e.g., Aon et al. 2001 , Eisenhauer mais aussi al. 2010 , Strecker ainsi que al. 2016 ). Furthermore, considering the harmful character away from ground testing, i always had to attempt additional positions inside a good subplot, meaning that it is impossible with this particular method of realize the same place owing to go out. With the piecewise SEM if in case actually correlating spatial and temporal balances, we sumpling feel in order to mediocre spatial stability for every area to use a shaped dating services Artist Sites strategy. To check on the result out of forest variety richness into spatial and temporary stability of floor basal respiration, surface bacterial biomass, surface water stuff, teas size losings, and floor epidermis temperatures i utilized linear mixed-effects habits that have “experimental take off” (having spatial and you may temporary stability) and “testing knowledge” (getting spatial stability) from the haphazard construction. A mathematical notation of the patterns (based on Gelman and you may Hill ( 2007 )) are in Appendix S1: Section S4).