Growing city populations and limited space are driving the adoption of green roofs and green walls covered with living plants. As well as boosting biodiversity, green roofs could play another unexpectedly valuable role by increasing the electricity output of solar panels.
At that point you might as well just place an entire agrivoltaic system on your roof, although it requires significant structural support and you would be living underground.
Agriculture is terrible for biodiversity and so are cities. This is one way of supporting more biodiversity in areas where it is already struggling.