The notable discovery is that, where the evidence a few decades ago was that the bison were breeding in their historical herds (so multiple, smaller genetic poo

The notable discovery is that, where the evidence a few decades ago was that the bison were breeding in their historical herds (so multiple, smaller genetic pools), they now appear to be breeding between herds (so a single larger, more diverse genetic pool). AIUI with small populations, more variation in breeding between groups is a good thing, because it spreads genetic diversity across the whole population.