The total number of native and alien plant species recorded across 183 protected areas in the United States (see Suppl. material 1: Table S1 for the park names). Data were derived from the IRMA portal (https://irma.nps.gov/NPSpecies, accessed May 2018).

 
 
  Part of: Moodley D, Foxcroft LC, Novoa A, Pyšková K, Pergl J, Pysek P (2020) Invasive alien species add to the uncertain future of protected areas. NeoBiota 57: 1-5. https://doi.org/10.3897/neobiota.57.52188