Law of Tolerance

A law developed by Shelford (1911) which states that the success of an organism is dependent on a range of environmental conditions, having minimum, optimum and maximum values, which can be tolerated for successful development to take place. Optimum values for environmental conditions allow for good, strong plant growth and reproduction to take place, however, as conditions move towards minimum and maximum values then this increases stress placed on plants reducing their abundance and durability. Conditions with values outside of the maximum and minimum range, result in an intolerable environment in which the plants will be eliminated.