City dwellers seldom experience the near-reverence of watching deer walk through their yards, both for a lack of deer and, often, a lack of a yard. In cities, not everyone has the same experiences with nature. That means that the positive effects of those experiences—such as mental health benefits—and the negative effects—such as vehicle strikes—are unequally distributed. Urban ecologists have proposed that income and biodiversity may be related, such that a so-called "luxury effect" may lead to more biodiversity in landscaped, affluent suburban neighborhoods.