During the long period of their formation bog habitats have slowly grown and have kept a hidden history of their development and the changes in the landscape around them over thousands of years.
Mae'r mawn sy'n cronni yn y mawnogydd yn cynnig cyfle i astudio holl hanes datblygu'r ecosystem drwy gyfrwng gweddillion y planhigion a fu'n gorwedd yno am filoedd o flynyddoedd.