AUGUSTA, Maine — Although Maine’s non-white population rose 37 percent between 2000 and 2010, the state’s three largest metropolitan areas rank in the bottom 25 in a new Brown University study on racial and cultural diversity in the United States.

Bangor places fifth from the bottom. Portland-South Portland-Biddeford ranks 11th, and the Lewiston-Auburn area fills the No. 25 spot. Laredo, Texas, with a population described as 95.7 percent Hispanic, holds the title of least diverse community for 2010, the final year of Brown’s 30-year study period. Of the 25 least diverse metropolitan areas, 23 had populations identified as at least 91 percent white. Almost all are located in the Northeast or Midwest.

The study measured how evenly population is spread across five groups: Hispanics of any race, non-Hispanic whites, blacks, Asians and “others,” which includes non-Hispanic Native Americans, other races and multi-racial people.

As an aging, 95.2 percent white state tucked into the far corner of the Northeast, Maine has been much slower to move toward the “increasingly multi-hued, multi-lingual, multi-ethnic” American society described by the study’s authors. The state is not bucking the trend toward diversity, it’s just moving much more slowly than other parts of the country, according to Charles Colgan of the Muskie School of Public Service.

“Focusing on Maine’s relatively small share of diversity can obscure the changes that have been occurring,” Colgan said. He noted that every Maine county showed an increase in ethnic and Hispanic populations between 2000 and 2010, but because the state is so predominantly white and older — with slow population growth — cultural change occurs at a slower rate.

“Virtually all types of communities have become more racially and ethnically diverse since 1980.

However, they vary in the magnitude of diversity, its composition, and its pace,” according to the study titled “Racial and Ethnic Diversity Goes Local: Charting Change in American Communities Over Three Decades.”

Maine lacks many of the factors that expedited diversity in other U.S. communities, most of which are located in the nation’s largest cities, especially in the South and West. Ten of the study’s top 15 most diverse metro areas are located in California.

The study lists the military, higher education and government as “institutions that value racial and ethnic equality,” thereby promoting diversity. The closure of air bases at Limestone and Brunswick since 1980 drastically reduced the military’s diversifying presence in Maine. No federal government facility on the scale that would trigger major demographic changes exists in Maine. Student populations at the state’s public and private colleges expand overall diversity, but not to a degree that significantly alters patterns in Maine’s metropolitan regions, according to the study.

Conversely, “diversity might be lower in retirement-specialized communities where elderly whites’ preferences for racial homogeneity, coupled with expensive living costs, deter minority residents,” the study states.

The study suggests that shifts toward more diverse communities will affect the economy, school systems, social services, politics and “cultural cohesion, as reflected in common values, religious traditions and language.”

“I think the lack of diversity in population, while not a major factor in the economy, is something that Maine will have to pay attention to,” Colgan said. “As the United States becomes more ethnically and linguistically diverse, and as we integrate into a more diverse global society, it’s important that we have experience dealing with people from other backgrounds. Maine people can’t just talk to Maine people.”

Unfamiliarity with other cultures “makes it harder for Mainers to engage with people we will have to [in order] to make our economy grow,” Colgan said.

Tony Ricciardi, president of Listen Up Espanol, a Portland firm that operates a Spanish language call center in Hermosillo, Mexico, agrees, but he says the Internet can accelerate Maine’s cultural amelioration.

“In business, I like diversity of mindset,” he said. “The Internet allows you to work and use mindsets of people all over the world.”

Ricciardi, who said he’s been “all over the country and chose to live in Portland because it’s a great place to bring up a family,” believes Maine could better leverage its excellent quality of life for economic gains.

“If we don’t have a deep ethnic culture here, we should ask ‘what is it that we have?’ and put a value on it rather than putting a light on what we don’t have,” he said. The value of ethnic and cultural diversity is that it “opens people’s eyes to what they can do and shows them that there’s more out there.”

Based on Ricciardi’s experience overseeing a Spanish-language call center in Mexico from Portland, “Technology can close the gap.”

The state’s political community mirrors the lack of ethnic diversity on its streets. Other than in very specific communities, ethnic and linguistic diversity has not manifested itself politically in Maine, according to Colgan. “We’re not exactly New Mexico,” he said, referring to a state led by a Hispanic governor since 2003.

The public education system in Maine’s largest cities will benefit from ethnic and linguistic diversity by “exposing kids at a young age to an ethnically diverse population,” Colgan said. However, the costs associated with educating more students with increasingly diverse cultures and with a wider array of primary languages will tax already strained education budgets, he said.

“I’m hoping the education system will use technology to connect cultures,” Ricciardi said, pointing to a program his firm launched that invites eighth-graders in Cape Elizabeth to create “infomercials” that go to the call center in Mexico as part of a cultural exchange and learning program.

The Brown study also highlights generational differences, concluding that, “Younger people who have grown up in diverse communities take this demographic profile as a given. But older whites who have watched the 30-year increase find themselves having to adjust their notion of ‘America,’ sometimes reluctantly.”

U.S. Census data show Lewiston-Auburn and Portland to be quite a bit more racially diverse than Maine as a whole — and Bangor to be slightly more so. The 2010 figures list Portland’s population at 83.6 percent non-Hispanic white, 7.1 percent black, 3 percent Asian, 2.7 percent multi-racial and 3 percent Hispanic or of Latin origin.

The 2010 figures for Lewiston are 85.5 percent non-Hispanic white, 8.7 percent black, 2.6 percent multi-racial, 1 percent Asian and 2 percent Hispanic or of Latin origin. Auburn is listed as 92.8 percent white, 2.5 percent black, 2.1 percent multi-racial, 0.9 percent Asian and 1.5 percent Hispanic.

Bangor’s population is made up primarily of 92.2 percent non-Hispanic whites, 1.7 percent blacks, 1.7 percent Asians, 2 percent multi-racial and 1.5 percent Hispanic.