I know from direct observation, that this species is spread via the guts of herbivores here. The seedlings appear en masse in the cow dung pads. It also appears with horse faeces. My sheep love it and all the heavily grazed paddocks are rose free. On the contrary I haven't seen it along usual bird dropping sites, where other berries germinate like quite a few Cotoneaster species. Of course I couldn't argue against bird dispersion but here the main way seems to be large animals. It is VERY invasive here. I spent the first 4 years cleaning my farm of it, and suckers kept sprouting everywhere. Initially it was an inpenetrable bramble. Complete hillsides are covered with it in fairly sandy, sunny positions, also windswept . I was only able to reduce the existing population to something manageable only after about 15 years...It is said that it was brought initially by the first European settlers in the beginning of the 20 th century across from Chile as a way of creating barriers/hedges against cows wandering into cultivated areas. Nowadays there's an industry developed around the medicinal use of the hips, included medicinal oils.The hips are used to make a hip jelly and sold as tourist novelty.
However as rose gardener I wonder if it can't be used as a rootstock, since its so well adapted here( or many other places as I read). I'm also interested around its disease resistance. I've not seen black spot on it. So clearly its a species that at least here has a lot to provide.