Do camels pose an environmental threat to kangaroos?
Feral camels have environmental, economic and cultural impacts in Australia's Northern Territory (Dept of Land Resource Management, Australia).

In central Australia, camels feed on more than 80% of the available plant species. Feral camels severely defoliate and suppress the recruitment of some shrub and tree species, with such impacts being greatly exacerbated in drier years (Dept of Land Resource Management). 

Feral camels have a noticeable impact on fragile salt lake ecosystems and waterholes, which are important sites for Aboriginal people and for native fauna (Dept of Land Resource Management). 

However, its impact on kangaroos may be the last of our worries. There are other, typically smaller, marsupials that cover the endangered species list in the NT, including the Western quoll, bandicoots and wallabies (Dept of Land Resource Management). Kangaroos thrive in the agricultural farmlands that now dot the nation.