From today's Washington Post about insect survey in a public garden in Delaware that found 135 species of bees, including specialist and generalists not previously known to be native to the area. A quote:
"The survey suggests that if enough home gardeners plant targeted plants, the bees’ habitat loss will be mitigated, and the bees will show up. “These are very small animals; you don’t need 100 acres to make an impact. A tiny bee can do well in a small residential setting,” Sarver said. “It’s a great opportunity for conserving biodiversity, but enough of us have to do it.”"