Web Map Tile Service (WMTS)
The Ecological Mapping Systems dataset can be added to ArcMap as a Web Map Tile Service (WMTS), therefore, you do not have to download the data in order to view it in ArcMap. In order to add the WMTS, open ArcCatalog, within the Catalog tree, expand GIS Servers, and double click "Add WMTS Server". A window will open for you to add the WMTS URL. Copy and paste the URL below and click "OK". You will then be able to add the EMS dataset to your data frame for viewing.