Recent population shifts have laid the groundwork for far-reaching political changes in the District of Columbia, including the almost certain loss of traditional clout for the older, more conservative people in the middle-class neighborhoods of the outer ring of the city.

Preliminary findings of the 1980 census incicate that innercity neighborhoods where young, affluent, mostly white, so-called urban pioneers have displaced the poor and assumed an active political role are likely to play an increasingly important part in city politics.

The incomplete but substantially conclusive data provide the first statistical indication here of what urban experts believe is a national trend accelerated in Washinton by the extraordinary rate at which neighborhoods in the nation's capital have been transformed.

The inner-city neighborhoods contain fewer people. As a result, the anticipated reapportionment of the city is likely to place older voters fron the areas that were previously more powerful into less populated wards where the younger voters have already achieved political dominance that far outweighs their numbers.

"You have the number of people going down, but the number of voters staying the same or even going up," said George Grier, an urban researcher with the Greater Washington Research Center. "You're very possibly going to have more voters than before. You have a young, proffessional class moving in."

Moreover, the experts and politicians agree that these newcomers are bringing their own set of values and demands that are in many cases different from those of the older-line Washingtonians. And these new Washingtonians. And these new Washingtonians are known for being more vocal and energetic in their political activism than the older voters already here.

As the newcomers become tax-paying property owners here, many of them begin using city services, and they will likely become more active in local affairs in order to have a say in the delivery of those services.

"You're going to continuously see a kind of political suburbanization of these urban areas," said Dennis Gale, an urban affairs professor at George Washington University and a recognized expert in city trends. "Many issues typical to white suburbanites -- trash collection, police protection, recreation services -- will now become the urban issues."

Gale said that these urban pioneers "have made an investment in inner-city living. They tend to be very active and throw their weight around, and they will push to get better services.

"You already see it. Go around Capitol Hill and count the number of police cars and helicopters. You didn't see that 10 years ago. Many of them [the newcomers] are going to have children, and they're going to have to ask tough questions like 'will I put my children in public schools?" I think the schools will be the major battleground in the next four years. We've already begun to see it with the debate over the academic high school, and that's just the beginning."

The latest available 1980 census data shows the District's population down to 635,233, a 16 percent drop over the last decade. The first census figures for Washington, released last year, broke the total number down by approximate neighborhoods (called "enumeration districts"), which population losses of each ward.

As Washington has lost population over the last decade, the data show, Ward 3, west of Rock Creek Park, traditionally one of the most politically active areas of the city that has swung many key elections, is now significantly larger than the other seven wards. It likely will lose population when the ward lines are redrawn by the City Council later this year.

At the same time, three transitional wards -- Wards 1, 2, and 6, which together compose the inner core of the city -- are now too small, in large part because of the influx of these new so-called urban pioneers, typically young couples with few or no children, who are replacing poorer Washingtonians with larger families.

In Ward 1, the area stretching from Howard University on the east to Connecticut Avenue on the west, power is likely to shift permanently west of 16th Street, to the Mount Pleasant, Adams-Morgan and Kalorama neighborhoods where voting turnout is already highest in the ward.

In Ward 2, the inner-city ward from Dupont Circle to Foggy Bottom, most redistricting scenarios have Georgetown, now in Ward 3, being attached to the western end of Ward 2, a move that could consolidate white political control over the ward. Many of the older and black residents of Shaw have been displaced by renovdation.

And in Ward 6, now the smallest ward and the one that has undergone the most significant urban revitalization, the urban pioneers have become increasingly politically active. Any redistricting plan that puts all of Capitol Hill together in that one ward could shift the political power permanently to the cluster of revitalized Capitol Hill neighborhoods.

The losers in the apparent shift of power are the traditional sections of the city and their social structures that make up old-line Washington. They are the predominantly black Ward 4, which includes the upper 16th Street area, Ward 5 in far Northeast, and Ward 7, the eastern-most tip of the city. aThese wards contain the largest numbers of registered Democrats in an overwhelmingly Democratic city, and until Barry's 1978 victory were considered pivotal to any Democratic primary victory.

In those three wards, the churches are an example of one of the old-line institutions losing power. The ministers, long believed to be politically influential, have already seen their power waning as more of their congregation members move out to the suburbs, those who remain grow older, and as the newcomers make Washington increasingly secular.

The ministers recently lost a major battle when they were unable to defeat a referendum in last November's election that would legalize some forms of gambling in the nation's capital.

Another likely loser is Ward 8, the southeasternmost end of the city with Anocostia at its center, where the decline of population has continued over the last decade but has not been counterbalanced by any significant revitalization.

Some signs of the changes have already become apparent to politicians in the transitional areas.

"They [the newcomer] are very vocal, very vocal," said Council member Nadine P. Winter (D-Ward 6), who represents Capitol Hill. "They have house meetings even before the furniture is moved in. They want the trash picked up and they want gun control. They're young, and they're professionals."

Winter said she neglected the impact of these newcomers until her 1978 reelection bid, which she barely won. "Were it not for the older residents, I would not have won last time," she said. "I had a rude awakening."

Winter said that since then "I've changed my style." She said she is getting ready for her possible 1982 reelection campaign by spending more time in the Capitol Hill precincts and talking to the newcomers.

Ware 1 Democratic Club chairman Jerry Cooper said, "The western side of the ware -- west of 16th Street -- is a catalyst for the whole ward. That area is turning much more white, and those people are beginning to get much more involved. You can see it, when you walk through Adams-Morgan and Mount Pleasant."

Cooper said the shift will be more social than political. "It will have an impact on our basic neighborhood structures. When the ward becomes afluent, you attract more affluent-type stores. It will affect the kind of life we have in the ward. You have so many old-line Washingtonians who are still here and are opposed to the new breed coming in."

Cooper said that despite the fact that the newcomers "vote more, because they are more affluent," he said he believes "it will take some time" before they can control Ward 1 elections.

Cooper pointed out that on the east side of the ward, which is predominantly black, "they have the numbers, and if they think somebody is trying to take something from them, they"ll get involved. They may not vote as ofte, but if you have controversy, it will automatically bring them out."