Final answer:
Density-dependent growth refers to the negative effect of population density on individual growth and population growth rate, especially as a population nears its carrying capacity. It includes factors like competition, predation, and disease, which increase with higher population density and impact individual growth rates and overall population dynamics.
Step-by-step explanation:
Density-dependent growth is the inverse relationship between population density and individual growth. This concept is observed since most populations experience growth in a logistic manner rather than an ideal, unlimited exponential way. Density-dependent factors can significantly slow the growth of populations as they near their carrying capacity, leading to higher mortality rates and reduced birth rates.
These regulatory mechanisms are influenced by biotic elements such as predation, competition for resources, accumulation of waste, and disease. For example, when a population density is high, competition for limited food resources can lead to malnutrition and increased juvenile mortality, as witnessed in the natural experiment with wild donkey populations in Australia. Meanwhile, a low population density can sometimes have a positive effect on growth and reproduction, an effect known as an Allee effect.
It is essential for wildlife biologists and ecologists to understand the interplay of density-dependent regulation and density-independent factors. This knowledge helps them manage wildlife populations effectively, preventing both extinction due to underpopulation and problems with overpopulation.