Supplement 1. Experimental data and metadata, pairwise phylogenetic distances, and algal species descriptions.

File List metadata.csv (MD5: 2511c0d61b2b0dcf5ad32ff0e241cb1d) experimental_data.csv (MD5: 46d4e769aa936ebeb42ce326ed685d62) Pairwise_PDs.csv (MD5: 6a1d85a375afc2ce09a7d9a75e763aa7) Species_details.csv (MD5: 16b40b08d40f42d86c789fc1260abfd2) Description The Metadata file describes the contents of the other supplemental materials. The first column, “Tab”, identifies in which supplemental file a variable appears. For each variable (listed under the column entitled “Header”), the units, a short description, a full description, and notes are listed. The Experimental Data file is organized by experimental bottle (column 1), followed by descriptions of that bottle's treatment, focal species, invader species, and inoculation density (columns 2–5). Day of experiment (DOE) is listed in column 6, which together with bottle (column 1) uniquely identifies rows. Columns 7–46 contain data collected from counts of algal focal species density performed on a hemacytometer, chlorophyll <i>a</i> fluorescence intensity measurements, information on whether a species successfully invaded a resident community for the invasion treatments, final day of exponential growth of the focal species, sensitivity calculations, and data from counts of steady-state density of each species in the multi-species mesocosms. Column 47 is reserved for notes about the quality of the data. Dots indicate that a variable has no applicable entry for that particular bottle and DOE combination. Full descriptions of the variables (column headers) in the Experimental Data are available in the Metadata file. The Pairwise Phylogenetic Distances file describes the phylogenetic distance (column 3) between every two species combination used in this experiment, where the species are listed in columns 1 and 2. A description of how the phylogenetic tree and distances were calculated is described in the main text Methods under "Calculating phylogenetic distance". The Species Details file describes algal cultures' (identified in column 1) original supplier and code (column 2), the NCBI Sequence Read Archive accession number (column 3), and data regarding cell biovolume for each culture (columns 4–7).