RootMassLoss_QualityExperiment_JenaExperiment (MainExperiment, 2014)

This data set contains mass loss of community roots decomposing in the common plot in the Jena experiment in 2014. The Metadata contains the Dataset ID in the Jena Experiment database and detailed information of column: 'plotcode' is plot ID in the Jena Experiment; 'bag_ID' is the ID for litter bags within each decomposition experiment; 'root_type' is the type of roots in the litter bags where plot coded for community roots, lolium coded for standardized roots; 'site' is the location of where decomposition happened; 'sector' is the subplots in common plot; 'mass_initial' is root mass in the litter bags before buried in the field and handling loss is seduced already; 'mass_remain' is root mass in the litter bags at each retrieval; 'date_in' is the exact dates when the litter bags were buried. In the form of DD-MM-YY; 'date_out' is the exact dates when the litter bags were retrieved. In the form of DD-MM-YY; 'actual_decomptime' is the exact days litter bags were in the field; 'massloss' is actual mass loss =100 - mass_remain/mass_initial*100; 'std_decomptime' is standardized days litter bags were in the field; 'std_massloss' is stadardized mass loss = massloss/actual_decomp.time*std_decomp.time

100062_CN_Root_Ratio_JenaExperiment (MainExperiment, 2013)

This data set contains C:N ratio of community roots used in the root decomposition experiment. Root samples were collected in 2013 in the Main Experiments. 'Plot' is plot ID in the Jena Experiment

Aboveground biomass across sown species richness gradient for each management treatment.

<p>Aboveground biomass at the end of the induced drought period in August 2008 (left column) and 2009 (right column) measured regrowth since the last cut (M2-types: June; M4-types: July). The ambient treatment is given in open circles (dotted regression line) and drought treatment in closed circles (solid regression line). Significant effects obtained from mixed models for every single management treatment per year: SR = effect of sown species richness (linear), drought = difference in drought and ambient treatments, * = p<0.05, ** = p<0.01, *** = p<0.001.</p

Summary of mixed effects models for aboveground biomass in August 2008 and 2009 to test for effects of diversity (numbers of initially sown species and functional group richness), management and drought treatments.

<p>Models were fitted by stepwise inclusion of variables and likelihood ratio tests (L ratio) were applied to assess statistical significance of variables (p-values). Significance is given with * = <i>p</i><0.05. ** = <i>p</i><0.01. *** = <i>p</i><0.001; df = degrees of freedom.</p

Summary of mixed effects models for resilience and proportional resilience of aboveground biomass of the first cut in spring 2009 to test for effects of diversity (numbers of initially sown species and functional group richness), management (separated into mowing and fertilizer amounts) and drought treatments.

<p>Models were fitted by stepwise inclusion of variables and likelihood ratio tests (L ratio) were applied to assess statistical significance of variables (p-values). Significance is given with * = <i>p</i><0.05, ** = <i>p</i><0.01, *** = <i>p</i><0.001; df = degrees of freedom.</p

Summary of mixed effects models for resistance and proportional resistance of aboveground biomass after drought in August 2008 and 2009 to test for effects of diversity (numbers of initially sown species and functional group richness), management (separated into mowing and fertilizer amounts) and drought treatments.

<p>Models were fitted by stepwise inclusion of variables and likelihood ratio tests (L ratio) were applied to assess statistical significance of variables (p-values). Significance is given with * = <i>p</i><0.05, ** = <i>p</i><0.01, *** = <i>p</i><0.001; df = degrees of freedom.</p

Climatic parameters measured on field site during the two study years 2008 and 2009 with reference period 1961–1990 measured by the German Weather Service DWD in Jena, city center.

<p>Values represent monthly means (temperature, soil moisture) or sums (precipitation).</p

Resilience of biomass over sown species richness for each management treatment.

<p>Resilience of biomass was calculated as the difference of drought and corresponding ambient treatments for the first harvest in spring 2009 (M2-types: June, M4-types: April). Regression lines are given for significant effects obtained from linear models for every single management treatment per year: SR = effect of sown species richness (linear), drought = difference in drought and ambient treatments, * = p<0.05, ** = p<0.01, *** = p<0.001.</p

Resistance of biomass production for 2008 and 2009.

<p>Resistance was calculated as the difference of drought and corresponding ambient treatments at the end of the drought period in August and was plotted against species richness (left) and management treatments (middle). Regression lines are given for significant effects of species richness. Proportional resistance (ratio of drought to ambient treatment) was plotted against management treatment (right). Management treatments are shown in white (M2F0), gray (M2F100), dark gray (M4F100) and black (M4F200).</p

Time course of the growing season, including management and drought interventions of our study system.

<p>Stars indicate fertilization dates, vertical lines show mowing dates and dashed area represents our drought period. Frequently mown grassland types (M4, solid line) had four cuts per year and therefore four growth periods (first to fourth GP) previous to every cut. Normal mown grassland types (M2, dotted line) had two cuts per year and therefore two growth periods. Aboveground biomass is plotted as mean standing biomass above cutting height for each mowing grassland type.</p