Good question, @Gregg. Based on the User’s Guide, it sounds like pollinator abundance is an index of abundance per pixel:
“The pollinator abundance for species s index on cell x, during season j, PA(x,s,j), is the product of available floral resources on a cell during a given season, weighted by a pollinator’s relative activity during that season with the pollinator supply and normalized by the floral resources index in surrounding cells such that:”
So the index can be used to compare relative abundances of different species at different places in the study area. And it does seem okay to sum the abundances (either across multiple species or across pixels in a region) to get a total. But that total is still an index , not an absolute number of pollinators. For example, the aggregate results in farm_results.shp do this sort of summing across pixels in each farm polygon, allowing comparison of abundances across farms.
Others with more expertise may want to correct me. Or if I’m correct, then we could be more explicit about this in the “Interpreting Results” section of the User’s Guide.