What are the main causes that change a population's density?

When a population reaches a high density, there are more individuals trying to use the same quantity of resources. This can lead to competition for food, water, shelter, mates, light, and other resources needed for survival and reproduction. As the population increases there will be more chances for the exploitation of natural resources. Low Per Capita Income. Low Quality of Life. Environmental Degradation and Others. Excessive deforestation and overgrazing by the growing population has led to land degradation.