Yellow-legged frogs were once common in high-altitude lakes in the Sierra Nevada mountains, but they have become increasingly rare. Trout feed on tadpoles and young frogs. Few lakes in the Sierra Nevada had any trout in them until a hundred years ago. At that time, many lakes were stocked with trout for recreational fishing, and now trout are common in virtually all bodies of water in the Sierra Nevada. Researchers removed the trout from one lake, and the frog population soon quadrupled. Since frogs are capable of moving several miles over land, removing trout from just a few lakes is clearly the way to restore the frog population to its former levels.

The arguer recommends that removing trout from a few lakes in Sierra Nevada is indisputably a good method for increasing the population of yellow-legged frogs in the region. The arguer asserts that when trout was removed from one lake, the population of frogs had quadrupled. The arguer utilizes this fact to conclude that removing trout from a few lakes will have similar effects for the entire region as frogs can travel long distances on land. However, this recommendation is fallacious, at least without additional evidence in its support.

The arguer does not eliminate other reasons that could have resulted in the increase in the frog population after the researchers removed trout from the lake. It is likely that the lake is a special case and that the conditions at the time when the research was being carried out were conducive for increase in frog population. Moreover, there is a need to address other aspects of the research as well. The arguer provides no information related to the other actions carried out by the research team. They might have altered the ecological balance of the lake as a part of their experiment. This might include sowing underwater plants, adding organic substances to the water of the lake etc. It is likely that these actions succeeded in creating an environment that allowed the tadpoles to survive. Moreover, it is likely that there were other forms of underwater life that fed on tadpoles and these were also removed along with trout. In the absence of such evidence, the arguer has unfairly linked the increase in the frog population to the removal of trout from the lake.

Moreover, the arguer has brought out that these lakes were used for recreational fishing. Therefore, regular human interference could have led to a disturbance of the ecological balance of the lakes. It is likely that the water of most of the lakes has been polluted to the extent that the survival of frogs is no longer possible without making efforts to restore the ecological balance of the lakes. Therefore, the contention that removing trout from a few lakes would suffice for an increase in the frog population is unwarranted.

Even if we assume that the removal of trout was actually the reason behind the increase in the population of yellow-legged frogs, one cannot be convinced that the conditions in all the lakes of the region would be the same. It is likely that the other lakes in the region are home to other forms of underwater species that feed on tadpoles. Moreover, there is no mention of the locations of the lakes where the arguer suggests removing trout. It is possible that the lakes may be in an area that is too hot for survival of yellow-legged frogs. As brought out in the argument, yellow-legged frogs were common in the high-altitude lakes of Sierra Nevada. It is likely that due to global climatic changes, the climate of the high altitude areas is no longer cold enough for the yellow-legged frogs to survive. The lake where the research was carried out was probably in the uppermost reaches of the region and therefore, the cold climate helped the frogs to survive. Therefore, the removal of trout from randomly selected lakes will probably not affect the population of frogs in a manner similar to that observed in the lake where the research was carried out.

In order to establish a concrete link between the removal of trout and the increase in the population of yellow-legged frogs, the arguer needs to provide additional information related to the research work that was carried out. Moreover, the reader needs to be educated about the climatic conditions that existed a century ago when yellow-legged frogs were commonly found in the Sierra Nevada region and it should be compared with the climatic conditions that exist today. In the absence of such information, the reader cannot be convinced that the yellow-legged frog population will increase by removing trout from a few lakes.