– Roberto Rodriguez works at a meatpacking company in Nebraska’s capital. For years, most of his colleagues were fellow Mexicans and Central Americans. These days, the men standing by his side increasingly are Middle Easterners.

“We communicate through hand signals,” said Rodriguez, who came here from his native state of Zacatecas. “Working with Arabs is something I never thought I’d be doing. I thought the pipeline of Mexicans was forever.”

In Lincoln, the face of immigrant labor is changing. Workers are harder to come by, and immigrant labor is no longer the exclusive domain of Mexicans and Central Americans. It’s a dynamic playing out across the U.S.

By 2020, the private sector will facing a shortage of 7.5 million workers, said Ali Noorani, of the National Immigration Forum, a Washington-based think tank, citing a study by the American Action Forum, a policy institute that promotes rights for immigrants.

“We are increasingly dependent on a combination of documented and undocumented workers, refugees with temporary worker status,” said Noorani.

The think tank’s more conservative counterparts at the Center for Immigration Studies, which favors stronger immigration controls, argue that higher wages would lure more American workers.

So-called labor shortages, argued Mark Krikorian, executive director of the CIS, “is a sign, information for the employer that they need to change their way of doing business. They need to consider things like automation, change their recruiting strategies. Pay higher wages and offer better benefits, like free van shuttle service to pick up workers.”

Some companies in the Midwest are literally rolling out the welcome mat for immigrants and refugees. Muslim prayer rooms, complete with rugs, have been installed for Middle Eastern workers. Some employers push for a more robust guest worker program to fill jobs once filled by Mexican laborers.

“We don’t have enough labor to meet demand,” said Clayton Naff, executive director of the Lincoln Literacy Council. “We are a major resettlement place for refugees, a magnet for immigrants, and like all America, we have many new Americans trying to integrate. We need workers to keep our community thriving.”

With baby boomers retiring and U.S. birthrates and migration from Mexico falling, the nation is relying on a mixture of immigrants and refugees to keep its labor force growing.

Immigrants make up about 17 percent of the U.S. labor force, with about one-quarter of those undocumented. Without the current rate of both legal and undocumented immigration, the total U.S. workforce would shrink dramatically over the next 20 years, according to a 2017 study by the Pew Research Center.

Many industries, particularly agriculture and construction, are already taking a big hit, said economist Pia M. Orrenius, an expert on labor and demographic changes at the Federal Reserve Bank of Dallas.

Meatpacking companies have tried recruiting white and black workers in Minneapolis, Chicago and Kansas City and most last no longer than a week, said Don Stull, an anthropologist and professor emeritus at the University of Kansas who has long studied the beef and poultry industry.