In short, Anthropogenic Biomes of the World, v1 is more robust for use in investigating current (year 2000) anthromes while the Anthropogenic Biomes of the World, v2 data are more appropriate for comparing trends over time.
The Anthropogenic Biomes of the World, v1 classification used statistical methods to identify and map anthromes using global data for human population density, land use and land cover, resulting in an empirical classification consisting of 21 anthrome classes, three of them wild. The classes (biomes) in the Anthropogenic Biomes of the World, v1 data are arrived at via a two-step cluster analysis of the global input data. This makes the resulting anthrome data more objective, but means the identification/classification of those biomes cannot be made consistent over time.
The Anthropogenic Biomes of the World, v2 data sets are based on the patterns identified in the original Anthropogenic Biomes of the World data set, but simplified to 19 anthrome classes (2 of them wild). The classified biomes are based on human population density and land use data using standard rules that allow consistent classification across time periods. This makes the Anthropogenic Biomes of the World, v2 data better suited for temporal analyses.