The short drive to the wide-open 9,300 acres of oak woodlands, native grasslands and vernal pools of the Santa Rosa Plateau Ecological Reserve on a 2,000-foot-high, flat-topped mountain above Murrieta is sort of like traveling in a time machine to the region's past.

Here one can visit a pair of adobes that, at the age of 150-plus years, are the oldest standing buildings in Riverside County and provide a glimpse into the early ranching days of the 1800s.

One can also stroll through groves of oaks and grassy prairies that have changed little since the days when American Indians roamed the area in search of food and when European settlers arrived.

And one can get a close-up look at some of the best remaining examples of seasonal ponds that spring up after winter rain. The vernal pools, a feature of Southern California's natural landscape that once dominated the coastal plain and well-watered inland valleys, have all but disappeared under the bulldozer's blade.

"Having it close to so many people ---- a quarter-million if you include Lake Elsinore, Wildomar, Murrieta and Temecula ---- is really a privilege, a special thing for a community," said Rob Hicks, a park interpreter for the Riverside County Regional Park and Open Space District, which maintains the reserve's visitor center, trail system and education programs.

"I'm looking at a line of cars coming down the Ortega Highway," Hicks said in a recent telephone interview from Lake Elsinore. "There is a snaking white line of lights coming down that mountain.

"Those people must be really weary after their long commutes. It's fortunate that the people around here have a place to go to on the weekends."

A place that might have been a lot different.

The inspiration

Had it not been for the efforts of The Nature Conservancy, an organization that purchases and preserves environmentally sensitive lands across the globe, and of a grass-roots group called Preserve Our Plateau, the plateau's rolling hills might have been paved over for houses, golf courses and a road to the coast. It might have looked much like the sprawling, rapidly growing suburban communities below.

The Nature Conservancy bought the first piece of the reserve ---- 3,100 acres ---- in 1984.

Then, Preserve Our Plateau's protests against thousands of proposed estate and tract homes triggered a joint decision by three agencies to purchase an additional 3,800 acres in 1991 for $35.4 million. Metropolitan Water District, which needed to buy a well-preserved slice of nature, anyway, to make up for habitat destruction from construction of Diamond Valley Lake, put up $15.4 million. The county then provided $15 million and the state added $5 million, Hicks said.

A short time later, the reserve acquired land next door owned by Temecula developer Bill Johnson.

And reserve operators are still obtaining land between the reserve's western boundary and the Cleveland National Forest to secure a permanent path for mountain lion and deer to follow between the two open-space areas. Hicks said more than half of the corridor is in place and the total amount of land under the reserve's control is 9,300 acres.

"The corridor isn't contiguous yet," Hicks said. "That's not crucial because there are still undeveloped lands being used (by the wildlife to travel through). But one day those will be developed. Hopefully, by then, that corridor will be completed to allow the bigger animals an avenue in which to move."

But the move to preserve the rich natural landscape of the plateau got started back in 1984 with The Nature Conservancy's initial purchase. And this year, the reserve is quietly marking the quarter-century milestone for the popular public park and science research area.

60,000 visitors

Every year, more than 50,000 people visit the reserve to hike and bike its trails, Hicks said. In addition, he said, more than 7,000 third-graders enrolled in Southwest County schools tour the area through a plateau education program. In short, close to 60,000 visit each year.

By far, the biggest attraction is the 25-acre vernal pool with a boardwalk that offers a prime viewing location for visitors. Carole Bell, reserve manager and an employee of The Nature Conservancy, said that during some winter and spring days, it is the destination for as many as 90 percent of visitors.

Hicks said the pools are home to numerous species, including garter snakes, frogs and extremely rare fairy shrimp.

"One of the species (Santa Rosa Plateau fairy shrimp) lives only on the plateau and is found nowhere else in the world," he said.

People also flock to the reserve to inspect the adobes, reached via a short hike from the large pool through oak groves and an opening at the edge of a mesa that affords a panoramic view of the valley, against a backdrop of snowcapped peaks.

Many, too, come to see more than 600 native plant species and the reserve's six distinct plant communities: vernal pools, bunchgrass prairie, coastal sage scrub, chaparral, riparian and oak woodland.

While many of the trees are coast live oaks common in the foothills of Southern California, there are stands of rare Engelmann oaks, too.

The latter are "drought deciduous," in that "when they need to conserve water, they drop all their leaves," Hicks said. "So when people come up this time of the year, some of the trees look dead. But they are just going into the dormancy stage until the rains return."

Of course, the fairy shrimp are dormant this time of year, too, Hicks said. As is another plateau resident, the western pond turtle ---- the state's only freshwater turtle.

"This time of the year, they are buried down deep in the ground to withstand the heat and lack of water that summer and fall bring," he said. "They will come out again once the rains return. Until they come back, everything just hunkers down and lays low and waits."

A dream

That annual cycle is a magical transformation that most Southwest County residents might have missed, Hicks said, had the area been developed.

However, Johnson, the developer, considers the way the reserve came together to be anything but magical.

In the 1980s, he said, he purchased 2,000 acres on the plateau for $18 million. But he ended up selling it for $3 million in 1992 at the height of a severe recession. Johnson maintains the property was devalued because environmental groups put pressure on local politicians to prevent development and because government officials wanted it to shelter endangered species.

And that shattered a longtime dream of his.

"One of my dreams was to own some of the Santa Rosa Plateau," Johnson said in a recent interview. "We were going to master-plan it up there and do some development."

Johnson said he hoped to use the property as a launching point for a 22-mile highway through the mountains to the coast.

"I wanted to build the Ronald Reagan Scenic Highway to San Clemente," he said.

He takes exception to the notion that development would have ruined the area. He said what he had in mind would have accented the natural beauty.

"We were going to put some residences up there and some golf courses, which I thought would have been a really scenic thing for the area," Johnson said. "I would probably have left 60 or 70 percent of it open."

Still, even with open space, Hicks is skeptical the public would have been able to enjoy the area, had the area been developed.

Hicks said the vernal pools probably would have become the project centerpiece, the way subdivisions are built around man-made lakes.

And Hicks said it's questionable whether adequate steps would have been taken to preserve the vernal pool watershed.

"If the vernal pools were going to be protected at all, I highly doubt that they would be open to the public," he said.

Call staff writer Dave Downey at 951-676-4315, ext. 2623.