Question

The red squirrel is a species of tree squirrel that can be found in parts of Europe and Asia. In an experiment, a researcher introduced small populations of red squirrels to two different ecosystems at the same time. One of the ecosystems was a large nature reserve. The other was a city park that was about one-fourth the size of the nature reserve. The graph below shows the red squirrel population in both ecosystems over three years.

red squirrel population graph

The graph shows that while the red squirrel population was higher in the nature reserve than the city park, the city park still had a carrying capacity significantly more than one-fourth that of the nature reserve. Which statement could explain why the carrying capacity of the city park was higher than expected?
A.
The nature reserve is much larger than the city park, so its carrying capacity is greater.
B.
The city park contains fewer natural predators of the red squirrel than the nature reserve.
C.
The red squirrels in the city park face intense competition for a limited number of resources.
D.
The red squirrels in the nature reserve are better adapted to live in their environment.

Answer 1

the number of trees in the city park may be limited by humans

the nature reserve may be much larger in area than the city park.

increasing human activity in the city park may disrupt mating opportunities.

Step-by-step explanation:

The carrying capacity of an ecosystem is usually determined by a combination of factors. Examples of such factors include the boundaries of the ecosystem, the climate, the type and amount of resources available, competition for those resources, and predation.

The researcher's experiment showed that, with respect to the red squirrel, the carrying capacity of the city park is much lower than that of the nature reserve. The possible explanations for this difference are numerous but might include statements like

the nature reserve may be much larger in area than the city park,

the number of trees in the city park may be limited by humans, or

increased human activity in the city park may disrupt mating opportunities.

Any or all of these factors may be responsible for the different carrying capacities of the two ecosystems.

Answer 2

B. The city park contains fewer natural predators of the red squirrel than the nature reserve.

Step-by-step explanation:

When compared to a nature reserve a city park really doesn't have any predators apart from some cats or birds. There really isn't much that can challenge the squirrel in order for their numbers to go down. There is no threat from food shortages and no threat from being eaten by larger animals that could live there.