The nature lobby moves off the trail and onto Capitol Hill. Rising grass-roots activism and greater clout in Washington have buoyed environmental organizations. But the movement faces internal disputes over approach and tactics in promoting its goals.

THE Sierra Club pushes Visa cards, the Natural Resources Defense Council spends more time in court than outdoors, and a group called Earth First! will not hesitate to sabotage a bulldozer or two to save a forest. Environmental groups have come a long way from their humble beginnings. They are more diversified and have more money, more power, and more members than ever before.

Distinctions among the groups - both in philosophy and tactics - illustrate a movement that has matured and broadened with age.

New leadership in 10 of the 15 largest organizations within the last two years is just one indicator of the pace of change.

Perhaps the most notable trend within the movement has been the growing focus on Washington, D.C. The majority of press conferences, meetings, staff, and major news items occur in Washington. With the nation's capital as the center, the environmental movement's success depends more on legal and political savvy than kinship with nature.

Whether in the halls of Congress or before the courts, environmental groups have never been more powerful and effective.

Perceived threats to the environment by the Reagan administration have also swelled the membership ranks of many groups, adding to their clout.

But just as these groups are fast becoming cozy with the Capitol Hill power-lunch crowd, some corn-on-the-cob conservationists in the rest of the country are feeling frustrated and betrayed. Many of them are forming their own community groups, and others are taking matters into their own hands.

Several trends are emerging that will reshape the environmental movement through this decade:

Growing political sophistication and effectiveness.

Increased professionalism among staff and management.

Close cooperation among groups.

Broadened and more stable funding.

More self-criticism.

A groundswell of grass-roots activism.

These organizations are now staffed with people who have more in common with their typical members (upper middle class and well educated) than with the early founders of the movement. Instead of recruiting new members in backpacking shops and on college campuses, groups now rent one another's mailing lists, conduct market surveys, and queue up at wealthy foundations for big bucks.

While the groups themselves are becoming more distinct - each one carving out its own territory of expertise - they are also cooperating more.

George Frampton, the new president of the Wilderness Society, says that environmentalists have decided that ``jealousy and fighting and competitiveness is hurting us. ... Sure, [we] are going to be competing for money and members and media attention ... but we are better off trying to work together.''

The ``Group of 10'' - an informal organization of the chief executives of 10 major environmental groups - has been meeting regularly since 1981 to coordinate activities. As a result, many projects are now co-funded. Press releases are often signed by multiple groups, and the dais at press conferences is usually shared by several organizations. Challenges in funding

The struggle for funds has created new approaches to raising money.

``Public-interest groups almost by definition are in constant financial crisis,'' says Mike Clark, president of the Environmental Policy Institute (EPI).

To get around these problems, environ mental groups have put a high priority on diversifying their income bases. Some groups are using bequest specialists, product catalogs, rental property, and even the selling of land once set aside to be preserved, as a means of generating new and stable sources of revenue.

The latest example of product marketing is the Sierra Club Visa card, which nets the club a percentage of all purchases ranging from 0.5 to 5 percent, depending on the item purchased. In the first two months of the program, the club pulled in $22,000, with only 14,000 cards issued. With more than 400,000 members, Sierra has enormous potential there. Several other groups are also issuing credit cards in a variety of programs.

In addition to the credit card program, the Sierra Club puts out a product catalog, which has increased profits 100 percent over the last two years. The catalog brought in $600,000 its first year (1982) and passed $2.5 million in 1986.

To some people, this sounds a lot like big business. But Joanne Hurley, director of public affairs with the Sierra Club, says the goal is to diversify its income base. She concedes, however, that some members ask, ``How could you do this to John Muir?'' Naturalist Muir founded the club in 1892.

Some within the environmental movement see these changes as a natural evolution - a maturation as the organizations simply become more professional. Others see it as a severing of the movement from its earthy roots and a transformation into bureaucracies run by eco-corporate lobbyists and professional managers.

One of the more vocal critics is George Reiger, a former editor with the National Wildlife Federation, who now writes on environmental issues. His concern began when he attended a meeting where the head of a large conservation organization was accompanied by his speech writer.

``I was appalled,'' he says. ``The passion of these groups should come from the top, not from a hired gun.'' Mr. Reiger has since written about the salaries paid to certain environmental executives (over six figures), despite threats that by doing so he would be cut off from access to the movement's leaders.

While this new professionalism makes environmental groups look and act more like the corporations they have traditionally opposed, even the movement's critics concede it is more effective.

The question some environmentalists are now asking is: at what cost? Reiger says: ``Some conservation leaders are so impressed with the life styles of the rich and famous... they lose touch with nature, outdoor recreation, and people in small towns who make $10 and $25 donations because that is all they can afford.''

The EPI's Mr. Clark says, ``The enticements of power are such that you get sucked into it. The danger is that if you don't remain accountable to the grass-roots groups, you simply become another lobbying firm.'' Earth First!

While the big national organizations are busy working out their political and financial fortunes, a growing number of environmentalists have staked out a different battleground. Frustrated by politics and compromise, many have taken action into their own hands.

Their activity took shape soon after the publication of a novel entitled ``The Monkey Wrench Gang,'' by Edward Abbey, in 1975. In the book, four characters meet on a river raft trip and get so disgusted with the destruction of wilderness areas that they decide to sabotage or, as some prefer to call it, ``ecotage'' human encroachments on the environment.

``The Monkey Wrench Gang'' was much more than an action novel. It became the handbook of radicalized environmentalists who had tired of writing letters or waiting for Washington to act. ``Monkeywrenchers'' took their protest to the field, putting spikes into trees to damage chain saws, pouring sugar and corn syrup into bulldozer fuel tanks, and chaining themselves to trees and rocks. Although not a formal organization, a loose-knit group of monkeywrenchers called Earth First! now has supporters all over the United States. One of Earth First!'s founders edited ``Ecodefense: A Field Guide to Monkeywrenching.''

The book provides a listing of damaging activities, while describing true monkeywrenchers as nonviolent and ethical. It states that its targets are ``machines and tools, not people.'' But lumber company representatives, even some Forest Service personnel, have referred to Earth First! members as terrorists. Mike Roselle, a founding member of Earth First!, counters this, saying that ``the real terrorists are the ones destroying the forests.''

The fact that Earth First! seems to attract a fairly broad spectrum of supporters reflects a growing feeling that traditional organizations and methods are not enough. Many Earth First! supporters dropped out of these groups because they wanted to take more direct action. Perhaps more than at any time since Earth Day, Americans are concerned about environmental issues.

``People are more aware,'' says Wilderness Society president Frampton, that the issues ``are not just luxury issues or leaf issues, they are issues that ... relate directly to the quality of life and health ... that affect the way people live, [for example] when they turn on the tap. ... [The issues are] beginning to come home.''

This growing public awareness, combined with a more sophisticated approach, promises to keep environmental issues at the top of the country's political agenda.

Next: How issues like toxic waste have prompted greater demand for legislation.