Nutrient enrichment increases invertebrate herbivory and pathogen damage in grasslands

This dataset contains data on leaf damage by invertebrates and pathogens derived in a globally-distributed experiment manipulating nutrient addition (Nutrient Network). In total we estimated leaf damage on 153 plant taxa from twenty-seven grasslands worldwide, under ambient conditions and with experimentally elevated nitrogen and phosphorus. Additionally, we give MAT and MAP from WorldClim 1 for each site and percent cover for each plant species in the respective plot.

Methods
For each species, we assessed the damage on one fully-expanded leaf from each of five individual plants per plot (if available). We strived to sample individuals from different parts of the plots, avoiding clusters of individuals as much as possible.  In addition, individual plants and leaves were sampled randomly with respect to the response of interest. For plants with stems, we chose leaves approximately halfway up the stem, and for plants without stems, we chose fully-expanded, mid-aged leaves. For each leaf, we visually estimated the area damaged by invertebrates (chewing and mining) and pathogens (rust, powdery mildew, other pathogens), using four categories (A= 0%, B= 1-5%, C= 6-25%, D= greater than 25%). For our analysis, we converted categories to numeric values that represent the midpoint of each range (A= 0%, B= 3%, C= 15%, D= 63%).