Only a decade ago, what fans used to call the downtown jazz scene was thriving in the geographical zone that supplied its name: Lower Manhattan. A new club called Tonic had just opened at the site of a former kosher winery. The tri-level Knitting Factory was still presenting adventurous music in TriBeCa, and its founder, Michael Dorf, was producing a sprawling summer jazz festival. Smaller spaces such as Context, Alt.Coffee, Fez, and the Internet Café also hosted frequent performances, with a tilt toward the visionary, the improvisatory, and the creatively offbeat.

But several generations of New York tradition, begun in the early 1960s, are coming to a close in the Lower East Side neighborhoods that once were the native grounds of such jazz giants as Sun Ra, Sam Rivers, Charles Mingus, and Albert Ayler. Rising real estate values and a boom in new high-rise developments have forced out Tonic, which closed in 2007. The Stone, an intimate space on Avenue C, abides, but its rent is subsidized by its founder, the composer and MacArthur Foundation fellow John Zorn.

In fact, most of what used to constitute an East Village scene has been dispatched to Brooklyn, where many of the musicians and their audiences already live.

“It’s sad,” Bruce Gallanter said. “I’ve been going to gigs here since 1969, beginning with the loft jazz scene and on to the Knitting Factory [in the late 1980s], and it’s really drying up. There’s no place left to play.”

As a co-owner of the Downtown Music Gallery on the Bowery, Mr. Gallanter has operated one of the hubs of the community. It isn’t just a place to seek an out-of-print album by a favorite underground musician. It’s also where those same musicians go to hang out, either to do some shopping of their own or perhaps to perform at one of the regular Sunday matinees that, for now, have been put on hold. After five years in its current space, the Gallery is on a month-to-month lease and may have to relocate. Mr. Gallanter said his landlord wants to quadruple his rent. The retailer, whose shop is one of the very last old-school record stores in the city, could wind up in Queens.

But people aren’t going without a fight. During the past year, Rise Up Creative Music and Arts, a nonprofit group composed of about 200 performing artists, has been promoting the idea of a permanent performance space in the Lower East Side. Patricia Nicholson Parker, an activist, choreographer, and co-founder of the Vision Festival with her husband, the bandleader William Parker, has been producing weekly programs at neighborhood spaces such as the Living Theatre and the Clemente Soto Vélez Cultural Center, where the 13th annual Vision Festival was held three weeks ago.

“It’s not just about a gig,” she said. “It’s about having a place to play.” Working through the festival’s nonprofit entity, Arts for Art, Ms. Parker is aiming to raise $100,000 in matching funds for a capital reserve fund grant. The goal is to secure space at one of several locations in the neighborhood that the city owns, such as the basement of the Essex Street Market. “There aren’t any affordable neighborhoods left,” Ms. Parker said. “Everyone is scattered all over the place.”

Indeed, even the Knitting Factory, which now mostly books rock acts, can’t hold on to its turf. The club’s building on Leonard Street is for sale, and the venue is reportedly moving to Grand Street in Williamsburg, where it will take over the site of the former Luna Lounge (which shut down in April after relocating from the Lower East Side). Aaron Ali Shaikh said he is delighted by the news, because it augurs more foot traffic down the block. When he isn’t bartending next door at Spuyten Devil, Mr. Shaikh plays alto saxophone and promotes the New Languages concert series, which focuses on a generation of improvising musicians who mostly came of age after 1990.

The more, the merrier. “It’s great to be at a club or bar with great sound and not be in a black-box theater with crappy sound,” Mr. Shaikh said. Most of the shows at New Language are presented at the nearby Rose Live Music venue, and are likely to cross-pollinate genres, mixing a jazz set with a performance by a local rock outfit such as the Dub Trio or the Afrobeat ensemble Akoya.

“People who come out to see Akoya totally get [trumpeter] Taylor Ho Bynum,” Mr. Shaikh said. The overlap is natural. Members of indie-rock bands like the Yeah Yeah Yeahs and TV on the Radio are bending elbows at the same bars as the jazz musicians. Why wouldn’t they convene onstage as well?

Such multiplicity defines much of what is happening in Brooklyn, whether it’s at a Bushwick loft or Williamsburg bars such as Monkey Town or Zebulon, or in Park Slope at Barbes or the Tea Lounge. Such neighborhood focal points juggle jazz with experimental or world music, chamber strings or bluegrass, selling beer all the while to make the rent.

Suzanne Fiol has been running the Issue Project Room without such curb appeal since losing her space in the East Village in 2005. The performance space, currently located on the third floor of the Old American Can Factory near the Gowanus Canal, stages about 170 shows every year — anything from free jazz to contemporary chamber music to electronic compositions madly amplified over a 16-channel speaking array hanging from the ceiling, with an ongoing literary series and the occasional spaghetti dinner thrown in for good measure.

The concept seems to be working: The Issue Project Room won the equivalent of the nonprofit lottery when the DUMBO developer David Walentas invited Ms. Fiol to take over the 4,800-square-foot theater on the ground level of his 110 Livingston Street project in downtown Brooklyn. If, for years, patrons might have needed a flashlight to find IPR for the first time, it soon will be in walking distance of several major subway lines, as well as the downtown arts cluster anchored by the Brooklyn Academy of Music.

Ms. Fiol hopes to be in the space (which was gorgeously designed in 1925 by McKim, Mead & White) by next spring, and has launched a $2.5 million fund-raising campaign — an ambitious goal, but one strongly aided by having luminaries like the artist Robert Longo and actor Steve Buscemi on her board.

“I think they liked our energy, our passion,” Ms. Fiol said. “It’s a 20-year lease. You can imagine what that means for someone like me, who has moved three times in the last five years. It’s going to be great for Brooklyn.”

Since the building had been the headquarters of the New York City Department of Education, the city required Mr. Walentas to include a cultural organization in his plans for redeveloping the property. The developer is known for including arts outfits (such as St. Ann’s Warehouse and, more recently, the performance club Galapagos) in his matrix of DUMBO real estate projects, but the civic encouragement could not have hurt.

“Losing the Lower East Side does send a message out,” Ms. Fiol said. “And I think people are paying attention to that.”