The carrying capacity is a measure of how many individuals can a given ecosystem provide for. An individual and its population is dependent on various components of its ecosystem for necessities such as food, habitat, etc. An ecosystem can only successfully support a given population. If the population exceeds beyond that limit, in other words, if the carrying capacity is exceeded, the ecosystem will no longer be able to support the additional population. Such an excess causes chaos and then rebalancing of populations. For examples, if a grassland can only support, say 200 deer and the population exceeds that number (whether by additional births or by introduction of deer, etc.), there will not be enough food for all the deer. This will mean rapid decline in amount of grass in the grassland. Temporary increase in deer population will also provide additional food for predators and their population will also rise. But, ultimately, reduction in food will result in decrease in population of both deer and their predator and a new equilibrium will be established. Thus, ecosystem health is severely affected if the population grows beyond the carrying capacity.
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