Should I clear rapacious vines from my garden?

Question

My back yard is edged on three sides with something that was probably intended as a garden, but is now just an overgrown mess, with, e.g., lots of vines ensnarling everything. In the photo below you can see some of what I'm talking about (the lighter green leaves are the vines):

1. What is the vine?
2. Should I actually pull up all that stuff and let the intended plants breathe? Or does it create a healthy ecosystem or something to have all that stuff tangled up together?

Answer 1

The vine with the little purple flowers is Solanum dulcamara, aka Bittersweet Nighshade. It's toxic to most animals likely to encounter it. It makes a tangled mess wherever it grows. It's difficult to eradicate due to long, tough, and wideranging roots/stolons. And most of all it stinks to high heaven. There's nothing beneficial about it.