It was determined that rabbits continued to keep the plants nibbled down. Of particular concern is the effect rabbits exert upon freshly germinating trees and shrubs. In arid areas, shrubs grow slowly and don't necessarily produce a large amount of seed. Germination is sporadic and requires special conditions, usually including rain and sometimes chemicals released from the ashes following bushfires. If all new seedlings are removed eventually the older shrubs die and are not replaced.
Species become locally rarer and rarer until they eventually disappear.
Intensive grazing of this kind can wreck pastures for raising stock. The selective pressure of hordes of hungry little mouths taking the best plants as they emerge alters the balance of species in favour of those that are least palatable. Surprisingly, several authorities believe that rabbits only became pests in the latter part of the 19th century, after sheep had modified pastures in this very manner. From the opposite end of the scale, in much of the now rabbit-free regions following the calicivirus epidemic, it is abundantly clear that rabbits caused enormous environmental damage just through the emergence of seedling trees and shrubs that hadn't previously been able to establish for more than 50 years. Rabbits are truly prolific and opportunistic breeders.