Malaquías Gaspar left his farm village in southern Mexico when the economy soured in the mid-1990s. He headed north illegally and found the proverbial better opportunity in South Florida, where he made a decent living by picking fruit and building homes.

But the U.S. economic crisis has disrupted his life and the lives of countless other illegal immigrants who are now planning to leave or have already left.

Gaspar recently returned to Zimatlán de Alvarez in Oaxaca state, primarily to care for his ailing mother -- but also to plan for the future should the economy worsen in South Miami-Dade County, where his wife and four children remain.

''If we can't feed our children, we'll come back,'' said Gaspar, 40, as he sat at his family home -- upgraded with money he had sent from South Florida.

Gaspar is among millions of undocumented immigrants facing new challenges brought on by slim prospects for legalization, more aggressive federal enforcement and a worsening economy. Now, fewer immigrants are caught while trekking through the dangerous Sonoran Desert or risking their lives aboard makeshift boats in the Caribbean, indicating that fewer are trying. Those who make it through can find themselves on one of several daily federal charter flights that return deportees.

The ripple effects are already being felt. Communities in Latin America and the Caribbean report a reduction in remittances -- money sent home from the United States. That money is critical to the survival of families and the success of local civic projects. Border communities that once thrived as way stations for those heading north are now little more than ghost towns.

SMUGGLING RECEDES

Even on the tiny Bahamian island of Bimini, long a hotbed of eager smugglers willing to transport human cargo to South Florida, the mood is grim.

''The large groups are not coming as much as they used to, but . . . people who want to make money nefariously still view this as an opportunity,'' said Jeff Dubel, public affairs officer for the U.S. Embassy in Nassau, the Bahamian capital.

The Center for Immigration Studies, in a report published in July, was the first to note that undocumented immigrants were leaving the United States. But the report, ''Homeward Bound,'' attributed departures to increased enforcement.

Later, the Pew Hispanic Center, a research group in Washington, suggested that fewer immigrants were arriving because of the economic slowdown and stricter enforcement. The report said that the illegal population had stopped growing and that it now stood at about 11.9 million, down by about 500,000 from a year earlier.

While the potential ramifications of a reduced flow of immigrants may not be evident in a recession, labor shortages could emerge once the economy improves.

''In a bad economy, U.S. workers may temporarily take those jobs that undocumented workers do, but once things turn around, we may see labor shortages if too many foreign workers leave,'' said Tammy Fox-Isicoff, a Miami attorney who specializes in business-related immigration.

Illegal immigrants not leaving the country are traveling to any city, town or region where jobs might be more plentiful. Businesses that depend on foreign labor are already seeing an impact.

PRESSURE ON FARMERS

John Alger, of Alger Farms in Homestead, said South Miami-Dade farmers are not hiring as many migrant workers because the economy is forcing them to reduce the size of the fields they plant.