Herbivore
In a highly productive system, the environment provides an organism with adequate nutrition and resources to grow. The effects of herbivores competing for resources on the plant are more complicated. The existence of herbivores can increase plant diversity by reducing the abundance of dominant species, redundant resources can then be used by subordinate species. Therefore, in a highly productive system, direct consumption of dominant plants could indirectly benefit those herbivory-resistant and unpalatable species. But the less productive system can support limited herbivores because of lack of nutrients and water. Herbivory boosts the abundance of most tolerant species and decreases the less-tolerant species’ existence which accelerates the plant extinction. Mediate productive system sometimes barely has long-term effects on plant diversity. Because the environment provides a stable coexistence of different organisms. Even when herbivores create some disturbances to the community. The system is still able to recover to the original state.