This is the data and code repository for the manuscript entitled "Nitrogen enrichment and foliar fungal pathogens affect the mechanisms of multispecies plant coexistence". DATA: data.txt Dataset collected in the PaNDiv experiment, a large field experiment in Münchenbuchsee (near Bern) which investigates the mechanisms by which nitrogen enrichment affects ecosystem functioning. The dataset is composed by the following elements: year --- 2017 or 2018 block --- experimental block in the PaNDiv experiment (1, 2, 3 or 4) plot --- experimental plot in the PaNDiv experiment (from 1 to 336) nitrogen --- addition of nitrogen to the soil (0 = no, 1 = yes) fungicide --- application of fungicide to the vegetation (0 = no, 1 = yes) treatment --- control, nitrogen addition, fungicide application, and their combined effect number --- replicate number of the focal species; numbers are repeated because it restarts with each target focal-neighbour species combination (not shown) focal_sp --- 8 possible species: tar_off = Taraxacum officinale cre_bie = Crepis biennis rum_ace = Rumex acetosa dac_glo = Dactylis glomerata ant_odo = Anthoxanthum odoratum cen_jac = Centaurea jacea sal_pra = Salvia pratensis pla_med = Plantago media biomass_i --- initial biomass of the focal plant (start of the growing season; February/March) biomass_f --- final biomass of the focal plant (end of the growing season; June) tar_off --- visually estimated cover for this species as a neighbour cre_bie --- visually estimated cover for this species as a neighbour rum_ace --- visually estimated cover for this species as a neighbour dac_glo --- visually estimated cover for this species as a neighbour ant_odo --- visually estimated cover for this species as a neighbour cen_jac --- visually estimated cover for this species as a neighbour sal_pra --- visually estimated cover for this species as a neighbour pla_med --- visually estimated cover for this species as a neighbour herbs --- visually estimated cover for non-target herb species in the PaNDiv experiment grasses --- visually estimated cover for non-target grass species in the PaNDiv experiment legumes --- visually estimated cover for non-target legume species in the PaNDiv experiment CODE: 001-optimx.R Code that uses maximum likelihood to fit population models to the data. Produces several datasets with model coefficients and AIC values. 002-model_sel_coefs.R Code to select the coefficients based on the best model and add the size effect of the focal plants when needed. Creates all interaction matrices and intrinsic growth rate vectors. 003-final_matrices.R Code to adjust the matrices for coexistence computing. 004-coexistence.R Computes structural coexistence outputs. Provides a clean dataset with structural niche differences, structural fitness differences, and other multispecies coexistence metrics.