Which of the following statements is not correct?

The statement that is not correct is "Territorial defence encourages food scarcity in a habitat". Territorial defense actually discourages food scarcity because it prevents other organisms from occupying the territory and consuming the available resources. The other statements are true: shortage of food can be caused by various factors such as pests, diseases, and neglect of farming; shortage of food can lead to competition, emigration, death, and decline in the rate of reproduction; overcrowding can lead to scarcity of food; and dispersal of seeds and fruits prevents overcrowding by allowing new individuals to establish in other areas.