Historic preservation groups these days behave much like any thriving community battered by storms.

On one hand, they advertise their assets and gains. National Historic Preservation Week, which starts tomorrow, this year emphasizes the flourishing field of neighborhood conservation. Groups here and all over the country will be sponsoring tours and exhibits, holding community workshops and otherwise publishing an array of efforts to bolster established neighborhoods, improve existing housing and mobilize public and private resources to help areas threatened by blight or insensitive development.

For instance, the National Trust for Historic preservation has just created an Inner-City Ventures Fund to provide leverage funds, in the form of matching grants and low-interest loans, to neighborhood self-help groups that want to acquire and rehabilitate housing for lower-income residents in historic districts. Launched with a $400,000 Interior Department grant and $100,000 National Trust money, the new fund is designed to spur about a dozen such projects in the next year.

On the other hand, however, preservationists also are mobilizing to fight the storms of the Reagan administration's budget cuts and policy changes, which threaten to shatter the established federal-state partnerships and, ironically, also could disrupt the movement's evolution toward more reliance on local decision-making and private initiatives.

The most immediate issue is budget cuts. While proposing to continue almost $5 million in grants to the National Trust, the administation wants to eliminate all fiscal 1982 matching funds for state and local preservation programs and rescind $8 million of the $32.5 million appropriated for fiscal 1981. The House may reject the recission, which immediately could halt several states' programs. However, Rep. John Seiberling (D-Ohio) and other sympathetic congressmen warned the annual conference of Preservation Action, the national lobbying group, this week that budget-cutting pressures make the fiscal 1982 outlook for this and other small grant programs look very grim.

The administration believes that state and local preservation programs have grown strong enough to continue their surveys and process nominations for the National Register of Historic Places without federal aid, Interior Secretary James Watt told the National Trust's annual meeting Tuesday. "I am confident that any state that really cares will do so," Watt said.

Those in the field assert, however, that state funding will be uneven and that federal administrative burdens actually may be increased. According to the National Conference of State Historic Preservation Officers, about 13 of the 20 employes in the "average" state office now do the work required by federal law, such as trying to ease the impact of federal actions on historic places and certifying private restoration and rescue projects for the popular federal tax incentives.

National Park Service director Russsell Dickenson, whose agency is absorbing the remnants of Interior's preservation programs, acknowledged this week that federal offices will have to take over "a variety of tasks." How this will be done is unclear.

The future of the tax incentives is the second major point of concern. Last year Congress approved a three-year extension of the provisions, which have stimulated over $1.1 billion in private investment in historic structures and districts since 1976. According to Watt, the administration supports the "continuation" and "enhancement" of these incentives. However, preservationists fear that they will be badly undercut by Reagan's overall tax proposals, meant to encourage investment of all kinds. They prefer the alternative advanced by House Ways and Means Committee chairman Daniel Rostenkowski (D-Ill.), which includes special investment tax credits for rehabilitation of older and historic buildings.

Rostenkowski has become convinced that the special incentives "do some visible good" in cities, a Ways and Means staffer told the Preservation Action conference this week. Providing faster write-offs across the board will produce "more new construction and more in the suburbs," he said.

Finally, preservation groups are concerned about budget and policy changes at the Department of Housing and Urban Development, whose programs have become the largest federal stimuli for urban conservation and new uses of old properties.