All the Doon 18 Environmentally Sensitive Areas are marked as Penalty Areas comprising No Play Zones (NPZ) as defined by the Rules of Golf (2019).
They are marked with red stakes with green tops and there have been some "Do Not Enter" signs deployed from time to time on Doon 18 {holes 8 - 15 inclusive.} The No Play Zones occupy the whole of the Penalty Area where they are located.
They were covered under Local Rules on the older red scorecard which remains the latest documented description.
"Do not Enter the marked conservation areas shown on the map in rust red. These Environmentally Sensitive Areas are home to many rare and regionally significant flora and fauna". The 'map' was on the scorecard.
For more information see the pages on No Play Zones and Local Rules