ATLANTA  The South has become the first region in the country where more than half of public school students are poor and more than half are members of minorities, according to a new report.

The shift was fueled not by white flight from public schools, which spiked during desegregation but has not had much effect on school demographics since the early 1980s. Rather, an influx of Latinos and other ethnic groups, the return of blacks to the South and higher birth rates among black and Latino families have contributed to the change.

The new numbers, from the 2008-9 school year, are a milestone for the South, “the only section of the United States where racial slavery, white supremacy and racial segregation of schools were enforced through law and social custom,” said the report, to be released on Thursday by the Southern Education Foundation, a nonprofit group based here that supports education improvement in the region. But the numbers also herald the future of the country as a whole, as minority students are expected to exceed 50 percent of public school enrollment by 2020 and the share of students poor enough to qualify for free or reduced-price lunches is on the rise in every state.

The South, desperate for a well-educated work force that can attract economic development, will face an enormous challenge in tackling on such a broad scale the lower achievement rates among poor and minority students, who score lower than average on tests and drop out more frequently than whites. Four of the 15 states in the report  Georgia, Louisiana, Mississippi and Texas  now have a majority of both low-income and minority pupils. Only one, Virginia, has neither.