Mark Stoneman is the owner of Ooyella, a property located near Gunning, New South Wales. The property is registered with the NSW Parks and Wildlife Service and is under a Voluntary Conservation Agreement. Logged extensively in the 1940s, this property still retains some old growth forest, as well as a diversity of Southern Tableland and south coast canopy species, shrubs, orchards and grasses. There are a number of ephemeral creeks crossing the property, some of which have dams that provide water for wildlife.
The sanctuary covers approximately 106 hectares of bushland populated by brittle gum (Eucalyptus mannifera), red stringybark (Eucalyptus macrorhyncha), scribbly gum (Eucalyptus haemastoma), silver-top ash (Eucalyptus sieberi) and argyle apple (Eucalyptus cinerea), among other species. Ooyella is an important part of a corridor of remnant vegetation between the forested lands to the north of Goulburn and Crookwell and the lands within and to the south of the Australian Capital Territory.
Many threatened animal species are present at Ooyella, including the powerful owl (Ninox strenua), glossy black cockatoo (Calyptorhynchus lathami), gang-gang-cockatoo (Callocephalon fimbriatum), barking owl (Ninox connivens) and pink robin (Petroica rodinogaster). The property may also feature yellow-bellied gliders (Petaurus australis) and spotted-tailed quolls (Dasyurus maculatus) that have been sighted near the sanctuary. The sanctuary also houses 16 species of jewel beetles (Buprestidae spp.), which rely on uncleared property to survive.