Crommelin was appointed an Order of the British Empire (M.B.E), Civil member, in recognition of service to the flora and fauna on 1 January 1959.

She visited Pearl Beach for the first time with her friend Charles Pryce in a small cedar sailing boat in approximately 1910.

Crommelin paid £84 for land[7] in Pearl Beach adjoining the Brisbane Water National Park.

In 1938, after canvassing support from various societies to which she belonged Warrah Sanctuary was proclaimed with Crommelin the founding trustee.

Crommelin constantly protested against the local destruction of flora and fauna, careless back-burning and debatable infrastructure developments.

In December 1946, Crommelin offered her Warrah Sanctuary to the University of Sydney with one condition: she could live out her remaining years on the land.