[1] He served on the New South Wales Threatened Species Scientific Committee from 2015 until publicly resigning in June 2017 in protest after the NSW Berejiklian government passed a bill granting heritage status to feral horses in the Kosciuszko National Park.

[2][3][4][5] Watson completed a BSc (Honours) in biology from Monash University in 1994 with a thesis titled "The dynamics of bird communities in remnant buloke (Allocasuarina luehmanni) woodlands".

Watson completed a PhD in 1999 at the University of Kansas, with a thesis "Temporal scale and the consequences of habitat fragmentation: Case studies on Mesoamerican highland birds"[6] based on fieldwork centered in Oaxaca, Mexico.

[14][15] Currently, his research focus is on the effects of mistletoe on tree health and soils, mostly in farming and production landscapes, including macadamia crops in Queensland,[16] the introduction of mistletoe in urban trees to increase biodiversity within the urban landscape,[17][18] and conservation of sandalwood in Western Australia.

[19] Watson developed the 'standardized search' using the Chao estimator equations to easily construct species accumulation curves in the field to ensure that wildlife monitoring between sites is comparable.