She said using green spaces as a means of achieving targets on flooding, urban cooling, health, localism and food growing can help raise their profile. Providing evidence of green space benefits was critical, she added.
Mathers was speaking at GreenSpace conference Sustainable Parks: Sustainable Futures in Liverpool on Tuesday (2 March).
She explained: "We have got some really tough times coming ahead. Most local authorities will be making spending cuts of five to 20% over the next few years. We can't think about environmental sustainability in isolation from social and financial sustainability."
Also speaking at the event were Royal Parks head of parks services Dennis Clarke, In-Place consultant Paul Hyde and the City of London's superintendent of Burnham Beeches Andy Barnard.
Mile End park director Mike Rowan, who was chairing the conference, added: "We have got a very important role as educators in sustainability."
- For more on the conference, see HW, 12 March.