How did doubling the rabbit population affect the grass, snakes, and hawks first

A doubling of the rabbit in a certain area will cause certain changes in the ecosystem, for some organisms will be good, for some not so much.

The doubling of the population of rabbits will mean that they will need much more food. That will lead to the grass being overgrazed, and it will start to decline.

On the other hand, the increased rabbit population means much more food, which will lead to an increase in the population of eagles who have the rabbits as pray.

Depending on the type of snake, if they are able to attack and consume the rabbits, than their population may increase slightly, but if not, than the snakes's population will decrease because of the increased number of eagles, who also see them as prey.