Environmental distance is a measure of the similarity in environmental conditions between two geographic locations (Keller et al. 2011). A low environmental distance value between two locations indicates high environmental similarity. The Marine Ecoregions Of the World (MEOW) biogeographic classification system divides the coastal, nearshore, and shelf areas of the world into a nested hierarchy of 232 ecoregions, 62 ecoprovinces, and 12 ecorealms (Spalding et al. 2007). In this dataset, environmental distances were calculated between each pair of MEOW ecoregions and ecoprovinces, using temperature and salinity data from World Ocean Atlas (2018).
The final dataset consists of two matrices, one for 232 ecoregions and one for 62 ecoprovinces. For each matrix, the ecoregions or ecoprovinces are listed in the same order in both rows and columns. Environmental distance values between each pair of ecoregions or ecoprovinces can be found at the intersection of row and column for the members of the pair. For some ecoregions, no temperature and/or salinity data were available in the World Ocean Atlas. Data gaps in the ecoregions matrix are indicated with NA.