Final answer:
Mesquite seedlings struggling to grow near mature mesquite trees in dry areas show negative density dependence because they are outcompeted for scarce water resources. Density independence and delayed density dependence do not apply here as the impact is directly linked to the presence of mature trees.
Step-by-step explanation:
In dry areas, mesquite seedlings do not grow near mature mesquite trees because the roots of established trees outcompete the seedlings for limited water resources. This scenario exhibits negative density dependence, as the presence and density of mature mesquite trees affect the survival and growth of seedlings. Negative density dependence means that as the population density increases, the population growth rate decreases due to increased competition for scarce resources such as water.
On the other hand, density independence refers to factors that affect the population regardless of its density, like a natural disaster. Delayed density dependence can occur when there is a time lag between the change in density and its effect on the population. However, in the case of mesquite seedlings, competition for water with mature trees happens relatively immediately, ruling out delayed density dependence.