As you can see in this food web, there are many species of animals in the desert that eat each other. The small rodents such as the kangaroo rat, the insects and smaller lizards eat the plants. Then those rodents as well as insects are eaten by larger insects like the scorpions, larger lizards, and also the snakes. Finally those animals are eaten by the carnivorous birds and foxes.
Some things that can lower population growth in this food chain is if one of the animals or plants were to go into extinct, having more predators for one animal, competition, and get a disease from another animal or insect. The fluctuations of the numbers dropping would be caused if there would be a drop in cacti which would cause the kangaroo rat to drop in numbers and cause the snakes to drop as well as the desert foxes, so having a drop in any of the animals could cause a major drop of animals in the food chain. There have been many invasive species in the desert one of them are the red imported fire ant. The red imported fire ant is a small reddish brown ant imported from south america, they are small but highly aggressive. They inject a necrotising, type of venom when they sting. The stings result in painful, itchy, and persistent pustules, and sometimes in severe allergic reactions. The red imported fire ant has colonies that are extremely destructive. They dominate their home ranges due to their large numbers and aggressiveness. They also compete with other animals for food. They attack eggs and young of many bird (as seen in the picture below) and reptile species. The ants have significantly reduced northern bobwhite quail populations.