Montgomery College, a growing and expanding institution for the last 35 years, is entering a decade of austerity that will require aggressive recruiting of students just to support operations at the present levels.

"The pool of 18-year-olds is diminishing, and there is a decline in federal support for education," warns Robert E. Parilla, who took over as president of the college eight months ago. "All those things suggest that . . . what we do in the 1980s will have to be very well planned."

The oldest community college in Maryland and one of the oldest on the East Coast, Montgomery College faces increased competition for students, escalating costs of operation and scarce financial resources that will have to be spread more thinly than ever.

As a commuter college almost totally dependent on automobile travel, it also faces the real possibility that soaring fuel prices will push costs of commuting above tuition charges by 1990.

These were among the major conclusions of participants in a two-day conference on the 1980s held last weekend. It was attended by college faculty members, administrators, students and community leaders.

Founded in 1946 as part of the Montgomery County public school system, Montgomery College has grown from a shoestring operation based at Bethesda-Chevy Chase High School to a 16,000-student community college spread over three campuses in Rockville, Takoma Park and Germantown.

Each year it draws 20 percent of all high school graduates in Montgomery County -- more than any other educational institution -- but as the size of each graduating class decreases during the 1980s those students will form a less significant percentage of the college population.

To take up the slack, argued faculty members and administrators, older students, handicapped students, senior citizens, foreign students, people changing careers and women returning to college after time out for children will have to be recruited.

Such students already are enrolling at Montgomery College, but if the institution is to remain viable during the 1980s their numbers will have to increase dramatically, conference participants were told.

To attract them, the college will have to develop sophisticated marketing techniques and it will probably have to redesign programs to meet new demands as they arise. Already it provides daycare facilities for women with young children and tuition waivers for persons over 60.

With a 34 percent drop forecast statewide in the number of seniors graduating from high school over the next decade, recruiting pressures for those seniors remaining will become more and more intense and it's likely that some colleges won't survive the crunch.

Nationally, according to one estimate at the conference, between 200 and 300 colleges will close their doors and go out of business during the 1980s.

Already, Parilla is selling Montgomery College to high school seniors on the basis that it's one good way of reducing costs of obtaining a college degree: Go to Montgomery College for two years, then transfer to a four year college. If the alternative is a place like Georgetown where total costs exceed $8,000 a year, the $1,000 it costs for a year at Montgomery would mean a savings of $14,000 on the total costs of a degree. Approximately 54 percent of the Montgomery high school alumni who graduate from Montgomery College enroll full time at a four-year college.

Martin More, 19, a 1978 graduate of Gaithersburg High School plans to be one of them.

Now in his second year in the business program at the college's Germantown campus, More observes that "it doesn't cost a whole lot and I really enjoy the school. They've got excellent professors and the classes are really small."

Next year, More says, he plans to transfer to Lehigh or Bucknell in Pennsylvania or George Washington University.

More enrolled at Germantown in September 1978, the month it opened, completing the last of the three campuses planned for the system. No new campuses are planned for the 1980s and beyond.

There may be some growth in number of students, but it will be modest, college officials say, and it will occur only if there is imaginative planning and recruiting.

"Intuitively," said A. W. Gault, director of finances at the college, "I say the 1980s are not going to be as good as the 1970s."

Warned Susan Nelson, a research associate at Brookings Institution, "Higher education is going to be in for some very difficult times. Our problems are serious and there are no solutions in sight."

Not only will colleges be competing with each other for the 18- to 22-year students, she said, but they will also have to compete with the military and the labor market.

At commuter colleges like Montgomery, she said, rising costs of gasoline could spark a movement away from commuting and towards residential colleges.

Although difficult times are forseen for the 1980s, community colleges are not likely to be the hardest hit, predicted Brent Johnson, executive director of the Maryland State Board of Community Colleges.

Most affected, he speculated, will be the state colleges, "which will be squeezed from above by the University of Maryland and from below by the community colleges."

Community institutions like Montgomery College with its broad-based clientele and programs, ranging from the traditional liberal arts to auto mechanics, real estate, wine tasting and yoga, will survive, but they will need to be far-sighted and resourceful.

"I feel excited personally to be involved professionally in this kind of an institution," said Parilla. "I like the idea that in a free, democratic society every individual, regardless of the accident of birth, has the right to a higher education."

"This college has done some tremendous things during its period of growth. Now, it is time to develop a refined planning process for the future."