Describe the potential effects when a keystone species is removed from a community.

Explanation:

A keystone species is the one which plays an important role in maintaining the structure of the ecosystem. On the keystone species many other species of the ecosystem are dependent upon.  

The potential effects associated with the keystone species includes the following:

1. No other species will be capable of filling the same ecological niche. Hence, the dependent organisms will suffer and the ecosystem will change drastically.

2. The ecosystem will be populated by the invasive species which will affects the population of native species.

the answer is:

carbon dioxide