Of course, all you'd have to do is visit New York City to see what how immigration leads to an incredibly dynamic economy. New York City is powered by the entrepreneurialism of Pakaistani, Chinese, Mexican, Dominican, West African immigrants--among others.
Here are two excerpts from "Fruits of Immigration..."
Most economic studies show that in the long run, immigrants don't lower Americans' wages, they raise them. According to a study by Professor Giovanni Peri of the University of California at Davis, forthcoming next week from the National Bureau of Economic Research, immigrants raised the wages of most native-born workers in California by 4% over 14 years, with no change for low-skilled workers and a 7% change for high-skilled workers.
These wage increases are based on changes in the long-run productivity of the economy. They occur because most immigrants have either lower or higher skills than native-born workers and are not competing for the same kinds of jobs. Most Americans don't want to pick fruit in California or get PhDs in science. With more immigrant talent, American businesses can expand, creating more jobs for everyone.