Scientists analyzed data collected over a period of years in a game reserve in South Africa to test the hypothesis that competition with lions limits the abundance of leopards in the same community. The game reserve encompasses a variety of habitats, from open grassland to wooded areas around rivers and streams. It contains most of the indigenous mammal species and the adequate availability of their prey. For the most part, the leopards and lions show similar habitat preferences in the reserve.

The mass of the average lion is about three times that of the average leopard. The scientists analyzed several factors that might influence the abundance of each population, including the sizes of the animals preyed on by each species (Table 1).

Table 1. The dietary composition of leopards and lions according to the sizes of their prey animals

Size of Prey Animal	Percent of Leopards’ Prey (±2SEx¯)	Percent of Lions’ Prey (±2SEx¯)
Small	34  ± 2	3  ± 1
Medium	63  ± 3	23  ± 2
Large	3  ± 1	36  ± 4
Very large	0	38  ± 3

Because competition with lions might affect the population size of the leopards, the scientists also analyzed data on the lion and leopard population sizes in the game reserve (Figure 1).

 

(a)  Describe what scientists mean when they refer to an ecological community such as that shared by the leopards and lions.

 

Question 2

(b) Using the template,  construct an appropriately labeled graph to represent the data in Table 1. Based on the data,  determine the most common size of the leopards’ prey animals and the most common size of the lions’ prey animals.

 

Question 3

(c) Based on the data in Figure 1,  describe whether or how the size of the leopard population appears to have been affected by the lion population over the period for which data were analyzed. The scientists also estimated the consumed biomass of the prey animals of the leopards and lions. They estimated that the lions annually ate a total of approximately 175,000  kg of prey animals. This included approximately 110,000  kg of very large animals.  Calculate, to the nearest whole number, the percent of the total biomass eaten by the lions that are composed of very large animals.

Question 4

(d) Based on the data in Table 1 and the biomass of the very large animals eaten by the lions,  predict the likely effect on both the lions and leopards if the availability of the very large animals becomes limiting in the reserve. After analyzing the data, the scientists claim that the leopards and lions coexist in the reserve through the use of niche partitioning. Use evidence from the data provided to support the scientists’ claim.