Argument84 [The following is a letter to the editor of an environmental magazine.]” Two studies of amphibians in Xanadu National Park confirm a significant decline in the numbers of amphibians. In 1975 there were seven species of amphibians in the park, and there were abundant numbers of each species. However, in 2002 only four species of amphibians were observed in the park, and the numbers of each species were drastically reduced. One proposed explanation is that the decline was caused by the introduction of trout into the park's waters, which began in 1975. (Trout are known to eat amphibian eggs.)" [Write a response in which you discuss one or more alternative explanations that could rival the proposed explanation and explain how your explanation(s) can plausibly account for the facts presented in the argument.]
This argument is related to the issue about the decline in the numbers of amphibians in Xanadu national park in view of the data of 2002 and 1975. The writer presents one proposed explanation about this decline: the introduction of trout, an animal species feeding on amphibians, in 1975. There are other more essential factors accounting for this decline, and I will present following. One possible reason for the declining results could be the errors or potential faults of the two studies. We suppose the results presented by the studies are true, but what if not? After all, the systematic errors caused by the performers and the method taken will for sure affect the results. Maybe in 1975, the performers wrongly included turtles as amphibians, but in 2002 study, turtles were classified into reptiles; maybe the measuring method for the study in 2002 was not suitable for an accurate approach, therefore leading to a declining results; maybe the performers of the study were just high-school students, who treated the data carelessly. Without sufficient information, these possibilities may all affect the result, ultimately leading to a declining one. Secondly, presuming the studies are well carried out and the results can reflect the truth, there are still other explanations for this decline. One reason could be the huge change in the environment. After all, there have been 27 years long. Maybe conditions of the water body--pH, salt composition and concentration, temperature, oxygen composition and so forth--deteriorate during these years due to the climate variations, human activities and other factors. Maybe toxic compounds and substances are released into the water due to the industrial activities, or human vandalism. As a result, the living conditions could be not that favorable for the amphibians, leading to a decline of the species. In addtion, except the potential deteriorating environment issue, there could be other species risking the amphibians. The Xanadu national park is a small but complex eco-system, consisting of enormous sorts of species. Different species will interact with each other in different ways as well. Maybe there are other predators against amphibians, like some fishes and snakes; maybe some species compete food against amphibians, therefore leading to the decline of amphibians; maybe some micro-organisms or viruses live on the amphibians and decrease the reproduction rate of them by influencing the metabolism within the amphibians. There are many possibilities which may really account for the declining issue of the amphibians, and the introduction of trout is just one of them. In retrospect, except the writer’s explanation—the introduction of trout--on the declining issue of amphibians in Xanadu national park, there are many other alternative factors that will account for this result: the validity of the studies, the environment factors, and the different complicated interactions between different species. In order to determine the real reason behind this result, further study should be conducted.