Final answer:
Negative density dependence includes factors like predation, competition, waste accumulation, and diseases, which increase in effect as population density rises.
Step-by-step explanation:
The most common factors that cause negative density dependence are largely biotic in nature. These include predation, inter- and intraspecific competition, accumulation of waste, and diseases such as those caused by parasites. As the population density increases, these factors become more significant, leading to higher mortality rates and decreased reproductive rates. For instance, denser populations may suffer from increased competition for resources, leading to food scarcity, or from rapid disease spread that affects large numbers of individuals.
An example of negative density dependence is when a large caterpillar population leads to a decrease in food availability, which then causes the population to decline. In contrast to density-independent factors, which affect populations regardless of their size (such as a pesticide's impact), density-dependent factors intensify as population density increases. This mechanism helps regulate population sizes and prevent overexploitation of resources.