The National Trust for Scotland is expected to make job cuts as part of "radical changes" designed to reduce its running costs by 10 per cent a year.
The move was announced after a review of the 85-year-old charity led by Sir Moir Lockhead, its chair, Simon Skinner, its chief executive, and its board of trustees.
The charity said it did not yet know how many jobs might be at risk but was proposing a "thorough reconfiguration", which would "start at the top with the trust’s leadership and with layers of management being simplified".
The trust, which manages 129 properties, including Culzean Castle (pictured above), Glencoe and Culloden, employs 540 full-time equivalent staff and 750 seasonal staff. It has a further 3,000 volunteers.
The charity said that it expected to cut the total number of employees, staffing levels at its properties would be unaffected.
Under the changes, it said, specialist staff in a range of conservation and professional disciplines would be teamed with regional groupings of heritage sites to provide what would be, in effect, advisory services to properties. "These experts would be based out in the field, instead of at the trust’s headquarters," it said.
The charity said it would reshape itself over the next three to four years around priorities that would include advancing conservation to widen the appeal of heritage to more people in Scotland, putting significant investment in key properties in order to deliver world-class visitor experiences, and focusing accountability and decision-making at a local level.
A spokesman for the trust said it expected to begin consulting the trade union Prospect over possible changes in about April, with the aim of having any changes implemented by April 2017.
The charity had a total income of £46.8m in the year to the end of February 2015, down from £49.1m in the previous year, and spent £49.2m.
The trust said it would achieve more savings by changing the way it worked and making investment in modernised administrative systems and simplified processes.
It said that it aimed to make available an additional £8m to £10m a year in investment income because of a combination of the efficiency savings, more paying visitors, increased membership levels and growing donations.
Lockhead said: "This is an exciting new chapter in our 85-year history, providing new opportunities.
"Hard work has turned around the trust’s fortunes in the last few years, but we are now ready to move up to the next level to ensure we fulfil our mission of conservation in ways that are more relevant to today’s Scotland."
Ian Perth, negotiator for Prospect, said the union would do everything possible to defend employment levels at the trust.
"NTS has committed to ongoing dialogue with Prospect throughout the restructure," he said. "While we note the financial position of NTS, we want to ensure that, as a registered charity, NTS treats our members fairly and decently.
"We have several discussions planned in the coming weeks and months, and we hope that NTS can begin to bring clarity to our members as soon as possible."