Invasive milkweed in Europe reduces pollinator diversity

Common milkweed has become an invasive plant in Europe. There is actually a fair amount of research on this issue, where scientists in that region have been studying its effects, and even the best ways to combat it (glyphosate, ironically!).
While browsing this work I saw this latest study, which was published just weeks ago. In this paper the authors studied insect visitors at sites with and without common milkweed in Hungary. The authors walked transects through the sites and counted all pollinators that were visiting the native flowers present.
They found that at sites where milkweed had invaded, there was a lower diversity of pollinators like bees and wasps. That means there were fewer pollinator species present.
The authors speculated that the presence of large amounts of common milkweed attracts only the few “long-tongue” species (milkweed has long flowers), and the rest of the pollinators don’t bother to visit those invaded sites anymore.
As I said, there is more research on this issue, but a lot of it is similar. There is a tragic irony to all of this, where so many people in N. America are trying to enhance milkweed presence, while people there are trying to get rid of it. Andy Davis