Density-dependent factors are factors that limit population growth in a population based on its density or size. Here are brief descriptions of how each of the following density-dependent factors limit population growth:
i. Competition: Competition occurs when individuals of the same or different species compete for limited resources such as food, water, and shelter within their environment. As the population density increases, the competition for resources also increases, leading to decreased access to resources and reduced survival and reproductive rates of the individuals in the population.
ii. Parasitism: Parasitism is a relationship in which one organism (the parasite) benefits at the expense of another organism (the host). As the population density increases, the likelihood of parasite transmission also increases, which can lead to increased rates of infection, morbidity, and mortality in the population.
iii. Disease: Disease can spread more easily within a dense population, leading to increased morbidity and mortality rates. As population density increases, the frequency and severity of disease outbreaks also increase, leading to decreased survival and reproductive rates.
iv. Stress from overcrowding: Overcrowding can lead to stress in individuals due to increased competition for resources, increased risk of disease transmission, and increased aggression. This can lead to decreased survival and reproductive rates, as well as increased rates of behavioral disorders.
v. Predation: As population density increases, the risk of predation also increases, leading to decreased survival rates. Predators can more easily locate and prey upon individuals in a dense population, leading to increased mortality rates.
vi. Herbivory: Herbivores can consume a larger proportion of the available vegetation as population density increases, leading to decreased food availability and decreased survival and reproductive rates in the population.