Other forms: carrying capacities
In biology, carrying capacity is the maximum number of individuals of a particular species that an environment can support. In transportation logistics, the carrying capacity of a vehicle is how much it can hold.
There is only so much food, water, and living space in an environment, which means that it can't support an infinite population of any species. Without the chance to regenerate these resources, an ecosystem suffers. Ideally, populations level off as they reach carrying capacity, with roughly the same number of births and deaths. Exceeding carrying capacity results in overpopulation, which harms not only the environment but also the species itself as it runs out of the resources it needs to thrive.