There is a “deep sense of unease” among staff at BBC Radio Scotland after a succession of respected arts presenters, more than half of them women, were dropped from schedules.

The changes have prompted questions about diversity of coverage amid an apparent shift to a “more commercial sensibility” for the public broadcaster.

The Guardian spoke to a wide range of staff at the station who also raised questions about the treatment of one of their best-known presenters, Kaye Adams, who was sacked from her role presenting the Mornings show earlier this year after internal complaints about her conduct.

One employee said: “Staff are worried we’ve lost popular women presenters at the same time as an apparent move to a more commercial sensibility.”

The changes are part of a sweeping shake-up by BBC Scotland’s new head of audio and events, Victoria Easton Riley. This Friday, the three women who hosted the station’s afternoon culture coverage – singer Michelle McManus, poet Len Pennie and Nicola Meighan, one of Scotland’s best connected music journalists – will step down, despite latest Rajar figures indicating their shows were doing better than ever.

They will be replaced by one male presenter, Grant Stott, who will broadcast Monday to Thursday, and on Fridays by Arlene Stuart, who continues to work at Bauer Radio’s Forth 1.

Specialist late-night music shows hosted by Iain Anderson, Roddy Hart, Billy Sloan and Natasha Raskin Sharp were axed at the beginning of the year and replaced with a more generic pop show, Up Late, hosted by Lynne Hoggan, who also still works at Bauer, where Easton Riley was previously director of content for Scotland and Northern Ireland.

Last week, BBC Radio Scotland also confirmed two senior editorial appointments from the commercial station.

The Guardian spoke to a number of BBC staff who echoed recent staff survey results, which found a 33% drop in confidence in the executive team at the top of the BBC. Hayley Valentine, BBC Scotland’s director, acknowledged to staff that “change on the scale we’re facing can be unsettling”.

The complaints against Adams were investigated under the Call It Out scheme, which was launched after the Huw Edwards and Gregg Wallace scandals to instil confidence in staff.

But a number of colleagues who worked with Adams, including two who took part in the complaints inquiry, questioned why it resulted in repeated leaks. One said staff now had “zero confidence” in the scheme.

Colleagues also described the show as a “toxic environment” not of Adam’s making, where inexperienced young staff thrown in with no training or support was “an accident waiting to happen”.

In a statement in March, Adams wrote that reported claims she berated an intern and used a misogynistic slur were “simply untrue”.

One former colleague who worked with Adams as a young researcher said: “Newsrooms are pressured environments but directness is not the same as bullying. I only saw her being professional and fair, but she did have to deal with stupid mistakes, like when an influencer in her 20s was invited on to comment about menopause.”

Artists and musicians raised their own questions about BBC Radio Scotland’s priorities, with more than 300 signing an open letter organised by the Scottish Music Industry Association. The move prompted the former culture secretary Angus Robertson to request a meeting with the station to seek clarification over its commitment to emerging Scottish talent.

A data project set up by Stephen McAll of the folk band Constant Follower calculated that from January to May this year, compared with the same period last year, 23% fewer Scottish independent artists were played and 55% fewer female or female-led emerging Scottish artists.

A BBC Scotland spokesperson said their own analysis found the number of songs from Scottish artists before and after the late-night schedule changes was “broadly the same”, adding: “‘Our commitment to showcase the best from Scotland’s music industry, including unsigned bands, remains unmatched.

“We continually adapt and change our schedule to meet audience demand, and our decisions are informed by robust data and expert analysis”.

The spokesperson also said they were “proud to have added three new female presenters as part of our recent schedule changes”, naming Hoggan, Stuart and Connie McLaughlin, who replaced Adams as presenter of Mornings, and have presented across the station previously.

Responding to concerns raised about the Adams investigation, they said: “We don’t comment on individual cases. We do take any reports concerning our values not being upheld extremely seriously, and when required have robust processes in place to investigate.”