Minimize or eliminate use of pesticides in your yard. In addition to being an environmentalist, I'm also cheap and lazy, so I use pesticides only as a last resort -- for instance, dealing with Japanese beetles that nothing will eat, or killing poison ivy. I don't make blanket applications of anything, only spot-spray. Also I won't buy nursery plants pre-treated with pesticides; they're often labeled for neonicitinoids, and I tell vendors why I won't buy those. If I'm buying flowers, it's usually for the pollinators.
How to Attract Fireflies
I already do most of these things, and we have plenty of fireflies. But this caught my eye:
In some cases, “we still debate what constitutes a species,” says Eric Lee-Mäder, pollinator program co-director for the Xerces Society for Invertebrate Conservation. “Are two morphologically identical fireflies with different flash patterns two species—or one species with individuals speaking different languages? If we can’t answer that, how can we know how the insects are doing?”
I am now imagining some hapless alien trying to classify humans as species, based on things like color phase and communication, without being able to tell quickly and easily whether the groups are cross-fertile. LOL
Generally, I count species as separate if they are unable or unwilling to breed with each other. Sometimes they are biologically compatible but different cultures make their mate-selection methods mutually exclusive. Back when most human groups were endogamous and people traveled less, a case could've been made on those grounds that humans were different species. Of course, a look at human genetics indicates that different species don't stop them from fucking, and occasionally there are related species that are (at least sometimes) cross-fertile. We have subsumed the DNA of at least two or three other hominids.
Now imagine the poor aliens finding that we have wiped out all the other hominids except for the bits left inside us, like the fossilized remains of parasitic twins. Somewhere in the galaxy, someone is probably writing us as a natural-species version of the The Blob and submitting it to a horror magazine.