5. Dependence on a Balance of Populations—Dependance on Adaptations

Examining ecosystems in more detail, we discover a third aspect that is essential for sustainability. It is best revealed by asking questions such as:

What would happen if a primary consumer did not have predators? (See: goats overgrazing pacific islands/ rabbits introduced to Australia/ Elk in Yellowstone)

What would happen if a producer species, which could outcompete all native plants, was introduced? (See: kudzu invasion)

What would happen if a key predator species was eliminated? (see: elimination of wolves ecological impact)

 The conclusion to reveal is that a stable ecosystem is far from a random grouping of producers, consumers, and detritus feeders/decomposers. Each species is not only adapted to thrive in the given climate and weather conditions of the region. It is precisely adapted to all the other species with which it interacts. These precise adaptations mean, for example, that a rabbit can escape from a fox most times but not every time. This is to say that there is a dynamic balance between  populations of predators and prey such that populations of all are maintained within bounds. 

This concept of a dynamic balance among the populations of the various species involved is the third principle underlying ecosystem sustainability. It will be investigated further in lesson B-32.

Summarizing: there are there principles of ecosystem sustainability.

1. Recycling of nutrients
2. Running of solar energy
3. Maintaining a balance of populations