The carrying capacity for a species in an ecosystem is primarily determined by

The carrying capacity for a species in an ecosystem is primarily determined by the resources in the ecosystem.

Explanation:

The availability of food, raw materials, water and other resources in that ecosystem are those factors that is used for the determination of the carrying capacity. The factors such as nature, the levels of wastage accumulation, removal of very important things from the system also determines the carrying capacity. a system's carrying capacity may involve matters such as available supplies of food, water, raw materials, and/or other similar resources.

The main components that determines the carrying capacity of an ecosystem are food and other resources, provided, the humans must not disturb the ecosystem for their self survival. The resources limitations and their availability determines this factor to a greater extent.