Millions of pounds has been invested creating safe open spaces with good facilities where people can enjoy walks, jogging and exercise outdoors across Scotland since the 1990s.
But now The Heritage Lottery Fund (HLF), which has ploughed £43.5 million across the UK into improving open spaces since its inception, has claimed not enough is being invested by councils for their upkeep.
The organisation, which commissioned a UK-wide review of parks, said new ways must be found to generate money or park cafes and toilets face being closed or having reduced opening hours.
Grass and flower beds may end up being left uncut or untended and play areas less regularly cleaned, the report warned. It said cut-backs in the number of wardens could lead to a rise in anti-social behaviour and there is also the danger of land being sold off entirely to make way for new housing developments.
Colin McLean, head of HLF Scotland, said: "Scotland has a proud tradition of public parks, enjoyed by thousands daily. Highly valued and precious places, they are vital to the physical and emotional well-being of all our local communities.
"Following decades of decline, Lottery funding has revitalised parks across Scotland, but this reports shows that this investment is now at risk.
"We realise these are financially tough times and that is why we need collaborative action and a fresh approach to halt this threat of decline. Our parks are far too important not to act now."
The report, State of UK Public Parks 2014: Renaissance to Risk?, found 60 per cent of parks managers expected a decline in the condition of parks in Scotland over the next three years, due to average expected cuts to maintenance budgets of 11 per cent.
It warns that local authorities have no statutory requirement to fund and maintain them.
It bemoaned the lack of a national coordinating body able to champion the importance of parks, to assert their value to communities and the economy, and protect them for future generations to enjoy.
The HLF report underlines the importance of parks to the public, with 50 per cent of park managers reporting an increase of membership of friends groups in Scotland's parks over the last three years. With 34 million people estimated to make regular visits to parks, they are one of the UK's most heavily used public services. Across the UK 68 per cent of park users consider spending time in their local park as important or essential to their quality of life. This rises to 71 per cent in urban areas and 81 per cent for those with children under 10.
A spokesman for the Convention of Scottish Local Authorities could give no cast-iron guarantees at a time of austerity for councils. He said: "Scotland's councils are fully committed to the maintenance and upkeep of the many wonderful parks under their control. They realise the positive impact that they have on the health and well- being of communities.
"It is for these reasons that in these times of financial restraint they will do all that they can to protect them, but at the end of the day it will be a case of prioritisation and councils are required by law to present a balanced budget. Sadly, demand for council services always outstrips the ability to pay for them all."
Julie Procter, chief executive of Greenspace Scotland, a charity that aims to improve the quality of parks and other green areas, said: "The State of UK Parks report is a clear alarm call for parks and greenspaces in Scotland and the UK.
"With the pressures on council budgets, difficult decisions on priorities have to be taken. This report should give us all cause to reflect on whether the right decisions are being made."