School libraries are "standing on the edge of a cliff" as they contend with severe cuts and local authorities failing to understand their benefits, according to the Chartered Institute of Library and Information Professionals in Scotland (Cilips).
Provision across the country is due to be hit by cutbacks, with librarians facing job losses or having to work across a number of schools, the professional body says.
It recently emerged that East Renfrewshire is proposing to save pound;131,000 by getting rid of its full-time school librarians and replacing them with senior pupils and self-service points.
Cilips has collated other plans on its website, including Falkirk's proposal to "stop the school library service" that supports 13 full-time equivalent jobs and save pound;325,000 by shifting management responsibilities on to secondary schools.
Proposals already approved include sharing librarians between schools in Glasgow, and replacing librarians in North Ayrshire, South Ayrshire and Fife with library assistants. Some schools, such as Dumfries Academy, have handed responsibility for libraries over to English teachers, and a number of councils have reduced librarians' duties to term-time only.
Sean McNamara, policy and digital officer for Cilip in Scotland, said: "The handful of budget proposals released in recent weeks suggest that the next round of cuts will be severe for school libraries, with many authorities ending up with less than half of what they had."
The scale of the proposed cuts has emerged as school libraries around the country are hosting events for Book Week Scotland. Teaching unions have warned that a reduction in library staff could have a profoundly damaging impact on pupils.
Many schools already share librarians. East Ayrshire, for example, employs five to cover nine schools, while Renfrewshire stretches seven across 11 schools.
The controversial proposals have prompted Duncan Wright, librarian at Stewart's Melville College in Edinburgh, to start a Facebook campaign entitled Save Scotland's School Libraries.
"The school library service in Scotland is currently standing on the edge of a cliff," Mr Wright said. He added that the East Renfrewshire plan to rely on pupils rather than professional librarians was "particularly galling" and had filled him with "anger and despair".
East Renfrewshire council argued that it could make the changes without damaging the service, however.
Mr Wright, a board member of the School Library Association Scotland, said that a "postcode lottery" was emerging as some councils had "so far withheld the axe". Aberdeen, for example, still employs a full-time librarian in each of its secondary schools.
Larry Flanagan, general secretary of the EIS teaching union and a former English teacher, said: "Local authorities may view cutting back on school libraries as a soft target, but being a librarian is not just a question of stamping out books.
"School librarians are graduate professionals and often the linchpins of school literacy programmes, which may grind to a halt when they are removed."
Libraries were also crucial sources of careers advice, Mr Flanagan added.
Mike Corbett, an English teacher and national executive member of the NASUWT Scotland teaching union, argued that school librarians offered "vital support" to teachers and any cuts in staffing would damage pupils' educational prospects.
Cilips insisted that school libraries were being targeted for cuts because authorities had failed to recognise their impact.
Mr McNamara said: "A dedicated librarian has a vital role in preparing pupils for the challenges of life in the 21st century in areas such as internet safety, information and digital literacy and the encouragement of reading for pleasure."
US research indicated that librarians had a crucial role to play in improving scores in reading tests, even in schools with overall declining staff numbers, Mr Wright added.
Education directors' body ADES warned earlier this year that councils would increasingly have to consider unpalatable cuts now that options for easy savings had largely been exhausted.
With teacher numbers protected - although the long-term future of that arrangement has been thrown into doubt in recent weeks - ADES told the Scottish Parliament's Education and Culture Committee last month that discretionary services were being scaled back.
The Scottish Book Trust sprang into action this week to launch the Love Letters to Libraries project, encouraging people to write to their favourite school or local library. Submissions will be gathered as part of a campaign to protect libraries.
For more on funding cuts, see page 8