Nicola Sturgeon, Scotland's First Minister, has urged the UK government to provide assurances that European Union funds to the Scottish voluntary sector will be "fully replaced" after Brexit.
The EU awarded Scotland £817m (€941m) in the 2014 to 2020 programming period.
It is not yet known how much of this went to the voluntary sector, but £28.6m went to the Scottish government's third sector division alone.
Speaking yesterday at The Gathering, the annual networking event run by the Scottish Council for Voluntary Organisations, Sturgeon called for clarity on future funding.
"At the moment, our third sector benefits significantly from EU funds," she said. "We will lose access to almost all of these under Brexit.
"As yet the UK government has failed to provide any detail on future funding arrangements.
"Earlier this month, the Scottish government joined with you in calling for clarity on this issue, and we will continue to do that until we have an assurance that that funding will be fully replaced."
John Downie, director of public affairs at the SCVO, told Third Sector that Brexit threatened the survival of parts of the Scottish third sector.
Downie said: "The loss of EU funding will devastate Scotland’s third sector and the people and communities it supports, particularly employability programmes.
"The SCVO and various senior charity officials have warned for a long time about the impact Brexit will have and there are concerns we could lose parts of the third sector completely."
Funding was one of several "very specific implications" of Brexit for the third sector, Sturgeon said during her speech.
She also highlighted uncertainty over the status of the 200,000 EU nationals from outside the UK living in Scotland as a "huge concern".
"That’s why we continue to make the case that Scotland needs the power to tailor its own immigration policy to suit our needs and priorities," she said. "Because we know that without inward migration our working-age population over the next few years might actually decline, which will result in less revenues to fund our public services."
Sturgeon praised the SCVO’s EUareValued campaign, which encourages EU nationals to continue living and working in Scotland.
The Scottish government set up a £150,000 Brexit Stakeholder Engagement Fund in May last year to work with 11 organisations, including Scottish Rural Action, YouthLink Scotland and Voluntary Action South Lanarkshire to consider the impact of Brexit on specific groups.
Sturgeon said the projects were "now reporting on their findings" and the information received so far "has confirmed that Brexit is causing great anxiety and uncertainty to individuals, businesses and communities across Scotland".
She added: "We will continue to work with all relevant stakeholders to plan how best to mitigate negative impacts wherever possible, while also calling on the UK government to rule out the disaster of a no-deal Brexit, which would be so damaging to all aspects of our society."