The following is a letter to the editor of an environmental magazine."In 1975 a wildlife census found that there were seven species of amphibians in Xanadu National Park, with abundant numbers of each species. However, in 2002 only four species of amphibi

It might seem logical, at first glance, that author’s conclusion that the main reason of sufficient declining of amphibians is introducing trout, which are known to eat amphibian eggs, into the park. The author’s conclusion is merely based on unfounded assumption and dubious evidence that introduced trouts ate lots of amphibians eggs and diminish its population. The argument from the one side is somewhat convincing, but the assumption neglects to look on the other substantial reasons that should be adressed, and, thus, the statement is not cogent enough to substantiate the argument.

First of all, the author claims that trough the extended period of time global water and air pollution were implicated but there is no evidence of how this changings influenced amphibian populatuion. For example, if scolars based on research find out that within those years air pollution were impaired to the level that made amphibians unable to reproduce, it will undermine the author’s argument that the main reasons are trouts. Contrary, if the author provides us with the information of the latest water and air probes that despite worldwide pollution, air and water within the area of the national park retains the same rates as it had in 1975, it will definetely strenghten the author’s statement.

In addition, author provides us with no pieces of evidence about rates of trouts to eat eggs of amphibians. In the national park as a preserved territory park keepers would not jeopardize surviving of one of the species by adding its predator. Most likely that these two species were separeted from each other.If true, the evidence that trouts have never ever taken the amphibians’nest will surely weaken this argument. Moreover, details about the ration introduced trout to amphibians might help to substantiate the argument. For instance, the ratio was so small that based scientific data trout could not destroy 3 species of amphibians and, therefore, this evidence would make the argument biased.

Finally, there is no evidence about conditions of the nature of Xanadu National Park in 1975 and now. Perhaps, the ponds where those disappeared species dwelt dessicated over that period of time and, therefore, the whole ecosystem was dstroyed including amphbias. In this case, evidence that some ponds or rivers in the national park stopped to exist will make the argument somehow invalid. It might be comparison of the maps for those two periods.

To sum up, this argue fails to substantiate its claim that the main reason of extreme declining of amphibians is trout which was introduced in the park in 1975 because the evidence cited in the analysis do not have enough support. It could be strenghten by providing facts of taking amphibians’ nests by trouts, in other way, we should be wary about accepting the truth of the argument conclusion.