Plans to build a fence along about 700 miles of the U.S. border with Mexico could mean the destruction of costly environmental restoration projects and could cut in to lucrative tourism and cross-border spending in the Rio Grande Valley and elsewhere in South Texas.

Congress approved a homeland security bill Friday that included $1.2 billion for fence construction.

Republicans in Congress, including Majority Leader John Boehner of Ohio, hailed the plan as "a giant step" in controlling the flow of illegal immigration across the U.S. Mexico border. But, environmentalists say the plan could destroy habitats and cut off access to water for numerous animals, including the already endangered ocelot and jarguarundi.

"They move back and forth across the water," said Mary Lou Campbell, a conservation chairwoman with the Sierra Club's Lower Rio Grande Valley Group. "When you isolate a species, you also (alter) their gene pool."

Some rare birds not found in other parts of Texas or the United States could also lose prey and either die off or be forced to leave the area in search of food, Campbell said.

The North American Butterfly Association, which runs the International Butterfly Park in the small border town of Mission, worries that the fence could cut off a part of their 72-acre park.

"It would have a huge negative impact on what we're doing," said Sue Sill, executive director of the park. "Seventy-two acres sounds like a lot, but it's not."

"We want our border secure, we want to be protected, but we also don't want to go overboard," Sill said. "We would hate to see the destruction of what we've already done."

Animals are not the only concerns in the Rio Grande Valley and South Texas, where crossing the international border is a daily event for thousands of residents in both Texas and Mexico.

Nancy Millar, vice president and executive director of the McAllen Chamber of Commerce's Convention and Visitors Bureau, said McAllen is a top shopping destination for Mexican nationals. A fence could stymie that economic traffic the community has come to rely on.

"The whole idea of a fence is certainly going to give a negative impression of our hospitality here," Millar said. "It depends on where it is built, but how could (Mexican tourists) not feel unwanted in our country?"

A negative impression could also deter eco tourists and the so-called "Winter Texans," retirees from the north who spend each in south Texas.

"Any way you look at it, it's bad news for the border," Millar said.