The supplementary materials for the study "Synthesis reveals approximately balanced biotic differentiation and homogenization" include figures and data files that support the main findings. Figure S1 illustrates species occupancy and richness changes across different scenarios. Figure S2 shows the central coordinates of the datasets used in the study. Figure S3 presents model estimates of change for each region across different scales. Figure S4 highlights the tendency towards biotic homogenization, particularly in datasets with only two time points. Figure S5 shows residual variation as a function of temporal duration for two sample types. Figure S6 demonstrates the association between biotic homogenization and datasets with only two time points, as well as intermediate to large temporal and spatial scales. Figure S7 shows relationships between changes in diversity and richness across scales. The data file S1 includes information on species occupancy changes, including gains and losses of high and low occupancy species. The supplementary materials also include a source data file with complete citations for the data sources used in the analyses. All models were fit to duration standardized log-ratios as described in the main text. The results indicate that biotic homogenization is strongest in datasets with limited temporal coverage and is more common at intermediate to large spatial and temporal scales. The study shows that changes in diversity and richness across scales are closely related, and that the balance between differentiation and homogenization is approximately maintained.The supplementary materials for the study "Synthesis reveals approximately balanced biotic differentiation and homogenization" include figures and data files that support the main findings. Figure S1 illustrates species occupancy and richness changes across different scenarios. Figure S2 shows the central coordinates of the datasets used in the study. Figure S3 presents model estimates of change for each region across different scales. Figure S4 highlights the tendency towards biotic homogenization, particularly in datasets with only two time points. Figure S5 shows residual variation as a function of temporal duration for two sample types. Figure S6 demonstrates the association between biotic homogenization and datasets with only two time points, as well as intermediate to large temporal and spatial scales. Figure S7 shows relationships between changes in diversity and richness across scales. The data file S1 includes information on species occupancy changes, including gains and losses of high and low occupancy species. The supplementary materials also include a source data file with complete citations for the data sources used in the analyses. All models were fit to duration standardized log-ratios as described in the main text. The results indicate that biotic homogenization is strongest in datasets with limited temporal coverage and is more common at intermediate to large spatial and temporal scales. The study shows that changes in diversity and richness across scales are closely related, and that the balance between differentiation and homogenization is approximately maintained.