The many and deepening cuts at newspapers across the country are starting to take a toll on their content, according to a study released today.

The challenge newspapers must meet immediately is to find more revenue on the Internet, according to the Project for Excellence in Journalism’s study, called “The Changing Newsroom: What is Being Gained and What is Being Lost in America’s Daily Newspapers.”

Newspaper managers need to “find a way to monetize the rapid growth of web readership before newsroom staff cuts so weaken newspapers that their competitive advantage disappears.”

Stories are shorter overall, the study found, and staff coverage tends to focus on local and community news.

“America’s newspapers are narrowing their reach and their ambitions and becoming niche reads,” the study said.

The reasons for the newsroom cutbacks are well known; newsprint costs have jumped, and advertising and circulation revenue have quickened their descent this year as advertisers follow readers online. Newspaper websites capture only a small fraction of the revenue lost as they sell fewer print ads, which fetch more money.

“The seams and threads are beginning to show in U.S. journalism even though newspapers are by far the greatest source of news,” Leon Ureneck, chairman of the journalism department at Boston University, said Friday.

The PEJ study surveyed senior newsroom executives at more than 250 newspapers and interviewed editors at papers in 15 cities to document the way these cuts have affected newsrooms and the quality of their product.

The results show that papers carry fewer stories on foreign and national news and devote less space to business, science and arts reporting, and many have reduced the crossword puzzle and eliminated television and stock listings.

Many editors said they must ask reporters to cover more beats, reducing their ability to produce authoritative stories. Others said, in what may create a vicious circle, that staff cutbacks reduce their ability to shape coverage to fit their communities’ needs.

Editors once leery of producing content for the web are increasingly embracing its potential to diversify readership and improve journalism, even if it sometimes saps print resources.

The web speeds delivery of news, allows interaction with readers and opens nearly infinite space for news.

“The downside is that it has eroded the advertising base in print publications, and that is by far the main source of revenue to pay for large news staffs,” Ureneck said.

Editors see the ability to track readership of any specific story online as an advantage for improving content. It provides an “indisputable link between strong editorial content and the kind of higher readership that attracts advertisers,” the study said.

The editors can then convince advertising sales staff to become more targeted in selling to the web.