Temperature, humidity, food and water are the four stimuli that is responsible for the decrease in the population of producers, consumers, and decomposers living in that area. If the temperature is too high or too cold, the growth of the producer stops and the plants can't tolerate the temperature will die. The death of producers causes the death of consumers because consumers depend on these producers for food. The population of decomposer also decreases if the environment is too harsh because decomposers also requires suitable environment for growth and survival. There is adverse effect on the energy pyramid, population, and community of organisms within the environment if these stimuli are not present in suitable range.
