From 1989 to 1990, Dato Sri Gathorne led the International Tropical Timber Organisation (ITTO) Mission, producing a policy-setting report for forestry management in Sarawak. Aligning with the goals outlined in the document, the Sarawak Forestry strives to designate 10% of the state as a Totally Protected Area.
In 1994, he supervised research on the biology and sustainable management of cave-dwelling swiftlets and their edible-nest, resulting in the publication "Swiftlets of Borneo: Builders of Edible Nests," a crucial conservation guideline. The publication serves as a key guideline for conservation, benefitting both swiftlets and local communities who rely on swiftlet nests for income.
Since 2000, Dato Sri Gathorne has resumed cooperative research into Malaysian zooarcheology, paleo-environments, and the biology of edible nest swiftlets. He serves as the Honorary Curator of Mammals at the Sarawak Museum and external adviser to Yayasan Ulin.
He remains a frequent visitor to Sarawak and Southeast Asia, leaving an enduring legacy through his foresight and passion for environmental conservation.