Sampling on 300 MultiTroph Plots

BEF China, Main experiment Sites A & B

Herbivory and Predation Rates on Leaf material

To quantify levels of herbivory and pathogen damage on planted trees along the species richness gradient, we conducted sampling on 277 plots during September and October 2023, including 140 plots on Site A and 137 plots on Site B. Our methods followed those established in previous studies based on visual estimations of damage (Schuldt et al. 2012; Schuldt et al. 2015). For each selected tree, leaves were sampled from three branches evenly distributed across the canopy, whenever possible. From each branch, 10 leaves were collected, resulting in a total of 30 leaves per tree. Only fully developed leaves from the current annual vegetation period were included in the sampling. The number of trees sampled in each plot varied according to species richness in order to achieve a comprehensive survey of all species present. This ensured a representative sampling of trees across different diversity treatments. The sampled leaves were visually inspected to estimate the percentage of leaf area missing due to herbivory and the percentage affected by pathogen infestation. These estimates were categorized into predefined damage classes, 0%, 1%-5%, 6%-25%, 26%-50%, 51%-75%, >76% (see also Schuldt et al. 2017). Damage estimates were cross-checked by a second assessor to ensure consistency and reduce observer bias. For each leaf, damage was categorized separately for herbivory and pathogen-related damage and were quantified as mean percentages per tree and aggregated to the tree and plot level. Predefined damage classes were converted to continuous values using mean values per damage class (Schuldt et al. 2015).