The United States retail sector is growing—in fact the number of retail jobs has climbed slightly over the past decade. Yet the broad numbers hide an otherwise sobering situation: that thousands of small-business retail jobs have disappeared.The Atlantic recently explained the changing nature of U.S. retail jobs and the devastating impact large superstores and online commerce has had on industries once dominated by mom-and-pop stores, such as florists and men's clothing stores. Retail’s share of the labor force has declined since the late 1980s. The culprit is big-box chains and the rise of Amazon and other e-commerce sites. Dubbed the "Walmart Effect," research has shown that one Walmart worker replaces 1.4 local retail workers, adding up to about 150 fewer retail jobs per county within a few years. Certain types of small businesses have been especially hard hit, The Atlantic explains:The death of the salesmen isn't a uniform trend. It's spiky. Supercenters nearly doubled their total employment this century. But music stores, photo stores, computer stores, and book stores have been crushed. These used to be services you needed a store to buy. Now they're apps.Other types of stores, such as flower and gift shops have been hurt by the rise of big-box retailers that sell the same products for less. For example, the number of jobs at florists has fallen 52 percent over the past decade, while gift shop jobs have declined 37 percent.Main Street stores shouldn’t despair just yet. As I explained back in November, there are ways that small and independent retailers can fight back against the Walmarts and Amazons of the world. For example, smaller businesses should avoid slashing prices to compete and instead focus on providing customers with extra perks that draw shoppers into their stores and make it worth spending a little extra. It also helps to make sure that a portion of items sold are unique products that can't easily be purchased for less online.Read more articles on hiring and firing.Photo: Getty Images