Winter sunshine and Hampshire's flora

It's been a beautiful sunny day. I caught this view of Winchester cathedral as we cycled to ukulele class this morning. 
This evening an interesting talk at RSPB group meeting by an eminent local botanist, Martin Rand, about Hampshire's changing flora. The fortunes of our native plants have waxed and waned  over thousands of years for numerous reasons, not only climate change, but because of human management of woodland and forest, grazing by sheep, cattle,  and deer, nitrogen run off from arable fields, to name a few. 
Then there are the introduced plants,  either by design, or accidentally, which have become important additions to our flora, perhaps in a good way like corn poppies, or causing a problem, such as with pygmy weed (Crassula helmsii) which is choking natural ponds.