Why is carrying capacity difficult to define?

Question

Why is carrying capacity difficult to define?

Answer 1

Hi,,,

The supportable population of an organism, given the food, habitat, water and other necessities available within an environment is known as the environment's carrying capacity for that organism. For the human population more complex variables such as sanitation and medical care are sometimes considered as part of the necessary infrastructure.

As population density increases, birth rate often decrease and death rates typically increase. The difference between the birth rate and the death rate is the "natural increase." The carrying capacity could support a positive natural increase, or could require a negative natural increase. Carrying capacity is thus the number of individuals an environment can support without significant negative impacts to the given organism and its environment. A factor that keeps population size at equilibrium is known as a regulating factor. The origins of the term lie in its use in the shipping industry to describe freight capacity, and a recent review finds the first use of the term in an 1845 report by the US Secretary of State to the Senate (Sayre, 2007).

Below carrying capacity, populations typically increase, while above, they typically decrease. Population size decreases above carrying capacity due to a range of factors depending on the species concerned, but can include insufficient space, food supply, or sunlight. The carrying capacity of an environment may vary for different species and may change over time due to a variety of factors including: food availability; water supply; environmental conditions; and living space.

Temporary exceptions:

It is possible for a species to exceed its carrying capacity temporarily. Population variance occurs as part of the natural selection process but may occur more dramatically in some instances. Due to a variety of factors a determinant of carrying capacity may lag behind another. A waste product of a species, for example, may build up to toxic levels more slowly than the food supply is exhausted. The result is a fluctuation in the population around the equilibrium point that is statistically significant. These fluctuations are increases or decreases in the population until either the population returns to the original equilibrium point or a new one is established. These fluctuations may be more devastating for an ecosystem compared to gradual population corrections since if it produces drastic decreases or increases the overall effect on the ecosystem may be such that other species within the ecosystem are in turn affected and begin to move with statistical significance around their equilibrium points. The fear is a domino like effect where the final consequences are unknown and may lead to collapses of certain species or whole ecosystems.

Possible expansion of carrying capacity:

Not all social scientists and demographers are convinced of an imminent carrying capacity crisis for humans. The Danish economist Ester Boserup has shown how technological developments in agriculture can increase carrying capacity, though not without limitations. Her work is summarized in the AAAS Population & Environment Atlas

hope this is helping

:-:NTS

Answer 2

Need to be more specific. For instance the carrying capacity of a river can change from a normal flow to overflowing it's banks or slow to a trickle depending on the source and rainfall.