About 75% of wild bees, and of course many other insect species such as digger wasps and sand wasps, nest in the soil and often the entire development cycle occurs there, in the holes and tubes where the brood lives.
If you want to support soil-dwelling species, like this "trouser bee" in the cover photo above, you can create a sand bed, or sandarium in new German, in your garden. With a bit of luck and if the location is protected against rain from above, even the ant lion will move into your new bed. He has developed a unique method to get prey. He lurks in the sand until an animal falls into his self-made funnel.

Funnel from ant lion
Ant lion hunting ground