Never think that just because you have a very small outdoor space you cannot include a worthwhile aquatic feature.
I have two tubs with water in, the main one being a 50cm diameter round container that holds 66 litres of water, which isn’t a great deal yet still makes a home for wildlife such as the damselfly, pictured here having recently emerged from its larval case:
All I grow in this tub of water is a dwarf water lily (which sadly never flowers), some water mint (very vigorous, but you can keep pulling it out as needs be), Parrot’s feather and Butomus umbellatus (Flowering rush), upon which this particular insect is sitting – oh, and a lot of algae, but that’s another story!
It sits above ground, so I’m sure it gets too hot in summer and probably freezes solid in some winters, yet still pretty much every year around this time I see damselflies emerging. As long as they have something to crawl up to get out of the water, and as long as I don’t clean it out in early spring and inadvertently oust the larvae, they seem to thrive in there.
So give it a go; you’re almost bound to be giving something a home!