In an experiment to determine the level of dependency between Leopards and the Antelopes was conducted. In the experiment, all animals that the Leopards could prey on were eliminated from the ecosystem. The only animals that were present in the ecosystem were thirty Antelopes and twenty Leopards. The two species were left to interact for a period of six months in the thick vegetative environment. Conditions were made suitable for all the animals in the ecosystem. For instance, water was easily accessible to all the animals. Records were kept for the period that the animals were kept. It was also ensured that there was not movement into or out of the ecosystem (Bernardo & Resetarits, 2001).
The periodical records which were taken after end of each two months reviewed very interesting results. It was observed that the number of Antelopes was reducing at a very high rate. The number was decreasing at an increasing number. In the first two months, five Antelopes had disappeared, in the second counting; ten of them were nowhere to be seen in the last counting; there was no single Antelope surviving. The number of Leopards increased by two in the first phase, in the second phase, the number shot up to twenty seven. However, in the last phase, the number mysteriously reduced to twenty.
What is the reason behind the reduction in number and the eventual depletion of all the Antelopes in the ecosystem?
Why did the number of Leopards initially increase in first two phases of the investigation and later reduce in the last phase?
Antelopes are a prey for the Leopards. The fact that there was no other source of food for the Leopards means that the Antelopes were the only food available (Morin, 1999). Thus their number thus was bound to reduce. On the contrary, the number of Leopards increased due to the availability of food. Some females gave birth during the period. The decrease at the end of the period is due to depletion of the only source of food.
Continued survival of the prey means an increase in increase in the number of predators.
If the number of Antelopes is increased after the depletion, the number of Leopards stops declining and after some time starts increasing. If all the Leopards are removed from the ecosystem, the number of antelopes increases at a steady rate.
Antelopes are left without the intervention of an external predator, however, Giraffes are introduced. The number of Giraffes and Antelopes are to be calculated after the period.
After six months it is observed that the number of both has increased by ten for Antelopes and three for the Giraffes.
The hypothesis is accepted. Leopards depend on the Antelopes for food in the ecosystems where there is no other prey available. Form the experiments, predators are a big threat to the increase of the prey. Leopards are therefore a big threat to the increase of Antelopes in ecosystems where there is no other prey to feed on.
Bernardo, R., & Resetarits, W., (2001), Experimental ecology: issues and perspectives, Oxford University Press US
Morin, P. J., (1999), Community ecology, Wiley-Blackwell Publishers