Final answer:
Increased predation on the vicuña population is a density-dependent factor because it escalates with an increase in population density, resulting in a higher mortality rate among the prey.
Step-by-step explanation:
The increased predation on the vicuña population would be considered a density-dependent factor. In biology, such factors are typically biotic and include predation, competition, and parasites. The impact these factors have on a population increases as the density of that population increases. For instance, in a denser population, predation can have a more significant impact because predators could find prey more easily, leading to a higher mortality rate among the prey. Consequently, the growth rate of the prey population may reduce.
Predation is a classic example of a density-dependent factor because the mortality rate due to predation usually rises with an increase in population density. In the case of the vicuña, if predation increases as the population density rises, then it can be directly linked to the density of the population. As the number of vicuñas increases, the likelihood of predators finding and killing vicuñas increases, thus making it a density-dependent process.