Even simple solutions are ineffective if folks don’t do the right thing.

Take litter, for instance. Americans have been hearing the obvious solution to the problem — don’t litter — ever since a Native American man shed a single tear in a commercial that was famous and ubiquitous during the 1970s. And yet the nation’s roadways still bear the evidence of thoughtless people who can’t be bothered to find a proper receptacle for their garbage.

Feral cats cause an arguably even greater environmental problem, as they prey on birds, snakes and other predators that have a role in reducing the prevalence of mosquitoes, rats and other pests. There is much for a community to gain by reducing the number of feral cats doing damage to that ecosystem.

The solution to the feral cats problem might not be as simple as the solution to the litter problem. Cats are long-lived, and they tend to proliferate naturally when left unchecked. But it’s clear that humans contribute to the problem.

If the only cats reproducing in the wild were feral ones, animal control departments and humane societies would soon begin to make a dent in the wild population through trapping and programs to spay and neuter those cats.

But many of the kittens born each year are the result of mating between outside domesticated cats and feral ones. The fertile domesticated felines thereby exacerbate the wild feline population problem.

Once again, the solution — at least to that part of the problem — is simple: Cat owners, especially those who allow their felines to roam, should spay or neuter their cats. But again, that solution is ineffective when irresponsible, thoughtless people choose not to do the right thing.